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Cary Clark2dc84ad2018-01-26 12:56:22 -05001#Topic Image_Info
Cary Clark137b8742018-05-30 09:21:49 -04002#Alias Image_Info_Reference ##
Cary Clark2dc84ad2018-01-26 12:56:22 -05003
Cary Clark61313f32018-10-08 14:57:48 -04004#Code
5#Populate
6##
7
Cary Clarkf895a422018-02-27 09:54:21 -05008Image_Info specifies the dimensions and encoding of the pixels in a Bitmap.
9The dimensions are integral width and height. The encoding is how pixel
10bits describe Color_Alpha, transparency; Color components red, blue,
11and green; and Color_Space, the range and linearity of colors.
12
13Image_Info describes an uncompressed raster pixels. In contrast, Image
14additionally describes compressed pixels like PNG, and Surface describes
15destinations on the GPU. Image and Surface may be specified by Image_Info,
16but Image and Surface may not contain Image_Info.
17
Cary Clark2dc84ad2018-01-26 12:56:22 -050018# ------------------------------------------------------------------------------
Cary Clark08895c42018-02-01 09:37:32 -050019#Subtopic Alpha_Type
Cary Clarkf895a422018-02-27 09:54:21 -050020#Line # encoding for pixel transparency ##
Cary Clark137b8742018-05-30 09:21:49 -040021#Alias Alpha_Type ##
22#Alias Alpha_Types ##
Cary Clarkf895a422018-02-27 09:54:21 -050023
Cary Clark681287e2018-03-16 11:34:15 -040024#PhraseDef list_of_alpha_types
25kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType,
26kUnpremul_SkAlphaType
27##
28
Cary Clark2dc84ad2018-01-26 12:56:22 -050029#Enum SkAlphaType
Cary Clarkf895a422018-02-27 09:54:21 -050030#Line # encoding for pixel transparency ##
Cary Clark2dc84ad2018-01-26 12:56:22 -050031
32#Code
Cary Clark61313f32018-10-08 14:57:48 -040033#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -050034##
35
Cary Clarkf895a422018-02-27 09:54:21 -050036Describes how to interpret the alpha component of a pixel. A pixel may
37be opaque, or Color_Alpha, describing multiple levels of transparency.
38
39In simple blending, Color_Alpha weights the draw color and the destination
Cary Clark61313f32018-10-08 14:57:48 -040040color to create a new color. If alpha describes a weight from zero to one,
41new color is set to: #Formula # draw color * alpha + destination color * (1 - alpha) ##.
Cary Clarkf895a422018-02-27 09:54:21 -050042
43In practice alpha is encoded in two or more bits, where 1.0 equals all bits set.
44
Cary Clarkffb3d682018-05-17 12:17:28 -040045RGB may have Color_Alpha included in each component value; the stored
46value is the original RGB multiplied by Color_Alpha. Premultiplied color
Cary Clarkf895a422018-02-27 09:54:21 -050047components improve performance.
Cary Clark2dc84ad2018-01-26 12:56:22 -050048
49#Const kUnknown_SkAlphaType 0
Cary Clark682c58d2018-05-16 07:07:07 -040050#Line # uninitialized ##
51 Alpha_Type is uninitialized.
Cary Clark2dc84ad2018-01-26 12:56:22 -050052##
53#Const kOpaque_SkAlphaType 1
Cary Clark682c58d2018-05-16 07:07:07 -040054#Line # pixel is opaque ##
55#Details Opaque
56 Pixels are opaque. The Color_Type must have no explicit alpha
57 component, or all alpha components must be set to their maximum value.
Cary Clark2dc84ad2018-01-26 12:56:22 -050058##
59#Const kPremul_SkAlphaType 2
Cary Clark682c58d2018-05-16 07:07:07 -040060#Line # pixel components are Premultiplied by Alpha ##
61#Details Premul
62 Pixels have Alpha Premultiplied into color components.
63 Surface pixels must be Premultiplied.
Cary Clark2dc84ad2018-01-26 12:56:22 -050064##
65#Const kUnpremul_SkAlphaType 3
Cary Clark682c58d2018-05-16 07:07:07 -040066#Line # pixel components are independent of Alpha ##
67#Details Unpremul
68 Pixel color component values are independent of alpha value.
69 Images generated from encoded data like PNG do not Premultiply pixel color
70 components. kUnpremul_SkAlphaType is supported for Image pixels, but not for
71 Surface pixels.
72##
73#Const kLastEnum_SkAlphaType 3
74#Line # last valid value ##
75 Used by tests to iterate through all valid values.
Cary Clark2dc84ad2018-01-26 12:56:22 -050076##
77
Cary Clarkf895a422018-02-27 09:54:21 -050078#NoExample
Cary Clark2dc84ad2018-01-26 12:56:22 -050079##
80
Cary Clarkf895a422018-02-27 09:54:21 -050081#SeeAlso SkColorType SkColorSpace
Cary Clark2dc84ad2018-01-26 12:56:22 -050082
83#Enum SkAlphaType ##
Cary Clarkf895a422018-02-27 09:54:21 -050084
85#Subtopic Opaque
Cary Clark682c58d2018-05-16 07:07:07 -040086#Line # hints all pixels are opaque ##
87Use kOpaque_SkAlphaType as a hint to optimize drawing when Alpha component
Cary Clarkf895a422018-02-27 09:54:21 -050088of all pixel is set to its maximum value of 1.0; all alpha component bits are set.
Cary Clark682c58d2018-05-16 07:07:07 -040089If Image_Info is set to kOpaque_SkAlphaType but all alpha values are not 1.0,
90results are undefined.
Cary Clarkf895a422018-02-27 09:54:21 -050091
92#Example
93#Height 64
94#Description
95SkPreMultiplyARGB parameter a is set to 255, its maximum value, and is interpreted
96as Color_Alpha of 1.0. kOpaque_SkAlphaType may be set to improve performance.
Cary Clark682c58d2018-05-16 07:07:07 -040097If SkPreMultiplyARGB parameter a is set to a value smaller than 255,
Cary Clarkf895a422018-02-27 09:54:21 -050098kPremul_SkAlphaType must be used instead to avoid undefined results.
99The four displayed values are the original component values, though not necessarily
100in the same order.
101##
102 SkPMColor color = SkPreMultiplyARGB(255, 50, 100, 150);
103 SkString s;
104 s.printf("%u %u %u %u", SkColorGetA(color), SkColorGetR(color),
105 SkColorGetG(color), SkColorGetB(color));
106 SkPaint paint;
107 paint.setAntiAlias(true);
108 canvas->drawString(s, 10, 62, paint);
109 canvas->scale(50, 50);
110 SkBitmap bitmap;
111 SkImageInfo imageInfo = SkImageInfo::Make(1, 1, kN32_SkColorType, kOpaque_SkAlphaType);
112 if (bitmap.installPixels(imageInfo, (void*) &color, imageInfo.minRowBytes())) {
113 canvas->drawBitmap(bitmap, 0, 0);
114 }
115##
116
117#Subtopic Opaque ##
118
119#Subtopic Premul
Cary Clark682c58d2018-05-16 07:07:07 -0400120#Line # stores components scaled by Alpha ##
121Use kPremul_SkAlphaType when stored color components are the original color
122multiplied by the alpha component. The alpha component range of 0.0 to 1.0 is
123achieved by dividing the integer bit value by the maximum bit value.
Cary Clarkf895a422018-02-27 09:54:21 -0500124
Cary Clark682c58d2018-05-16 07:07:07 -0400125#Code
Cary Clarkf895a422018-02-27 09:54:21 -0500126stored color = original color * alpha / max alpha
127##
128
129The color component must be equal to or smaller than the alpha component,
130or the results are undefined.
131
132#Example
133#Description
134SkPreMultiplyARGB parameter a is set to 150, less than its maximum value, and is
135interpreted as Color_Alpha of about 0.6. kPremul_SkAlphaType must be set, since
Cary Clark682c58d2018-05-16 07:07:07 -0400136SkPreMultiplyARGB parameter a is set to a value smaller than 255,
Cary Clarkf895a422018-02-27 09:54:21 -0500137to avoid undefined results.
138The four displayed values reflect that the alpha component has been multiplied
139by the original color.
140##
141#Height 64
142 SkPMColor color = SkPreMultiplyARGB(150, 50, 100, 150);
143 SkString s;
144 s.printf("%u %u %u %u", SkColorGetA(color), SkColorGetR(color),
145 SkColorGetG(color), SkColorGetB(color));
146 SkPaint paint;
147 paint.setAntiAlias(true);
148 canvas->drawString(s, 10, 62, paint);
149 canvas->scale(50, 50);
150 SkBitmap bitmap;
151 SkImageInfo imageInfo = SkImageInfo::Make(1, 1, kN32_SkColorType, kPremul_SkAlphaType);
152 if (bitmap.installPixels(imageInfo, (void*) &color, imageInfo.minRowBytes())) {
153 canvas->drawBitmap(bitmap, 0, 0);
154 }
155##
156
157#Subtopic Premul ##
158
159#Subtopic Unpremul
Cary Clark682c58d2018-05-16 07:07:07 -0400160#Line # stores components without Alpha scaling ##
161Use kUnpremul_SkAlphaType if stored color components are not divided by the
162alpha component. Some drawing destinations may not support
163kUnpremul_SkAlphaType.
Cary Clarkf895a422018-02-27 09:54:21 -0500164
165#Bug 7079
166#Example
Cary Clark681287e2018-03-16 11:34:15 -0400167#Height 64
Cary Clarkf895a422018-02-27 09:54:21 -0500168#Description
169SkColorSetARGB parameter a is set to 150, less than its maximum value, and is
Cary Clark682c58d2018-05-16 07:07:07 -0400170interpreted as Color_Alpha of about 0.6. color is not Premultiplied;
Cary Clarkf895a422018-02-27 09:54:21 -0500171color components may have values greater than color alpha.
172The four displayed values are the original component values, though not necessarily
173in the same order.
174##
175 SkColor color = SkColorSetARGB(150, 50, 100, 255);
176 SkString s;
177 s.printf("%u %u %u %u", SkColorGetA(color), SkColorGetR(color),
178 SkColorGetG(color), SkColorGetB(color));
179 SkPaint paint;
180 paint.setAntiAlias(true);
181 canvas->drawString(s, 10, 62, paint);
182 canvas->scale(50, 50);
183 SkBitmap bitmap;
184 SkImageInfo imageInfo = SkImageInfo::Make(1, 1, kN32_SkColorType, kUnpremul_SkAlphaType);
185 if (bitmap.installPixels(imageInfo, (void*) &color, imageInfo.minRowBytes())) {
186 canvas->drawBitmap(bitmap, 0, 0);
187 }
188##
189
190#Subtopic Unpremul ##
191
Cary Clarkfd32e722018-11-16 14:36:02 -0500192#Method static bool SkAlphaTypeIsOpaque(SkAlphaType at)
Cary Clark06c20f32018-03-20 15:53:27 -0400193#In Property
194#Line # returns if Alpha_Type equals kOpaque_SkAlphaType ##
Cary Clark09d80c02018-10-31 12:14:03 -0400195#Populate
Cary Clark06c20f32018-03-20 15:53:27 -0400196
Cary Clark06c20f32018-03-20 15:53:27 -0400197#NoExample
198##
199##
200
Cary Clark08895c42018-02-01 09:37:32 -0500201#Subtopic Alpha_Type ##
Cary Clark2dc84ad2018-01-26 12:56:22 -0500202
203# ------------------------------------------------------------------------------
Cary Clark08895c42018-02-01 09:37:32 -0500204#Subtopic Color_Type
Cary Clarkf895a422018-02-27 09:54:21 -0500205#Line # encoding for pixel color ##
Cary Clark137b8742018-05-30 09:21:49 -0400206#Alias Color_Type ##
207#Alias Color_Types ##
Cary Clark2a8c48b2018-02-15 17:31:24 -0500208
Cary Clark1a8d7622018-03-05 13:26:16 -0500209#PhraseDef list_of_color_types
210kUnknown_SkColorType, kAlpha_8_SkColorType, kRGB_565_SkColorType,
211kARGB_4444_SkColorType, kRGBA_8888_SkColorType, kRGB_888x_SkColorType,
212kBGRA_8888_SkColorType, kRGBA_1010102_SkColorType, kRGB_101010x_SkColorType,
213kGray_8_SkColorType, kRGBA_F16_SkColorType
214##
215
Cary Clark2dc84ad2018-01-26 12:56:22 -0500216#Enum SkColorType
Cary Clarkf895a422018-02-27 09:54:21 -0500217#Line # encoding for pixel color ##
Cary Clark2dc84ad2018-01-26 12:56:22 -0500218
219#Code
Cary Clark61313f32018-10-08 14:57:48 -0400220#Populate
221##
Cary Clark2dc84ad2018-01-26 12:56:22 -0500222
Cary Clarkf895a422018-02-27 09:54:21 -0500223Describes how pixel bits encode color. A pixel may be an alpha mask, a
Cary Clark09d80c02018-10-31 12:14:03 -0400224grayscale, RGB, or ARGB.
Cary Clark4855f782018-02-06 09:41:53 -0500225
Cary Clarkffb3d682018-05-17 12:17:28 -0400226kN32_SkColorType selects the native 32-bit ARGB format. On Little_Endian
227processors, pixels containing 8-bit ARGB components pack into 32-bit
Cary Clark4855f782018-02-06 09:41:53 -0500228kBGRA_8888_SkColorType. On Big_Endian processors, pixels pack into 32-bit
229kRGBA_8888_SkColorType.
Cary Clark2dc84ad2018-01-26 12:56:22 -0500230
231#Const kUnknown_SkColorType 0
Cary Clark682c58d2018-05-16 07:07:07 -0400232#Line # uninitialized ##
233 Color_Type is set to kUnknown_SkColorType by default. If set,
234 encoding format and size is unknown.
Cary Clarkab2621d2018-01-30 10:08:57 -0500235##
Cary Clarkf895a422018-02-27 09:54:21 -0500236
Cary Clark682c58d2018-05-16 07:07:07 -0400237#Const kAlpha_8_SkColorType 1
238#Line # pixel with Alpha in 8-bit byte ##
239#Details Alpha_8
240 Stores 8-bit byte pixel encoding that represents transparency. Value of zero
241 is completely transparent; a value of 255 is completely opaque.
242##
243
244#Const kRGB_565_SkColorType 2
245#Line # pixel with 5 bits red, 6 bits green, 5 bits blue, in 16-bit word ##
246#Details RGB_565
247 Stores 16-bit word pixel encoding that contains five bits of blue,
248 six bits of green, and five bits of red.
249##
250
251#Const kARGB_4444_SkColorType 3
252#Line # pixel with 4 bits for alpha, red, green, blue; in 16-bit word ##
253#Details ARGB_4444
254 Stores 16-bit word pixel encoding that contains four bits of alpha,
255 four bits of blue, four bits of green, and four bits of red.
256##
257
258#Const kRGBA_8888_SkColorType 4
259#Line # pixel with 8 bits for red, green, blue, alpha; in 32-bit word ##
260#Details RGBA_8888
261 Stores 32-bit word pixel encoding that contains eight bits of red,
262 eight bits of green, eight bits of blue, and eight bits of alpha.
263##
264
265#Const kRGB_888x_SkColorType 5
266#Line # pixel with 8 bits each for red, green, blue; in 32-bit word ##
267#Details RGB_888
268 Stores 32-bit word pixel encoding that contains eight bits of red,
269 eight bits of green, eight bits of blue, and eight unused bits.
270##
271
272#Const kBGRA_8888_SkColorType 6
273#Line # pixel with 8 bits for blue, green, red, alpha; in 32-bit word ##
274#Details BGRA_8888
275 Stores 32-bit word pixel encoding that contains eight bits of blue,
276 eight bits of green, eight bits of red, and eight bits of alpha.
277##
278
279#Const kRGBA_1010102_SkColorType 7
280#Line # 10 bits for red, green, blue; 2 bits for alpha; in 32-bit word ##
281#Details RGBA_1010102
282 Stores 32-bit word pixel encoding that contains ten bits of red,
283 ten bits of green, ten bits of blue, and two bits of alpha.
284##
285
286#Const kRGB_101010x_SkColorType 8
287#Line # pixel with 10 bits each for red, green, blue; in 32-bit word ##
288#Details RGB_101010
289 Stores 32-bit word pixel encoding that contains ten bits of red,
290 ten bits of green, ten bits of blue, and two unused bits.
291##
292
293#Const kGray_8_SkColorType 9
Cary Clark09d80c02018-10-31 12:14:03 -0400294#Line # pixel with grayscale level in 8-bit byte ##
Cary Clark682c58d2018-05-16 07:07:07 -0400295#Details Gray_8
296 Stores 8-bit byte pixel encoding that equivalent to equal values for red,
297 blue, and green, representing colors from black to white.
298##
299
300#Const kRGBA_F16_SkColorType 10
301#Line # pixel with half floats for red, green, blue, alpha; in 64-bit word ##
302#Details RGBA_F16
303 Stores 64-bit word pixel encoding that contains 16 bits of blue,
Cary Clark224c7002018-06-27 11:00:21 -0400304 16 bits of green, 16 bits of red, and 16 bits of alpha. Each component
305 is encoded as a half float.
Cary Clark682c58d2018-05-16 07:07:07 -0400306##
307
Cary Clark224c7002018-06-27 11:00:21 -0400308#Const kRGBA_F32_SkColorType 11
309#Line # pixel using C float for red, green, blue, alpha; in 128-bit word ##
310#Details RGBA_F32
311 Stores 128-bit word pixel encoding that contains 32 bits of blue,
312 32 bits of green, 32 bits of red, and 32 bits of alpha. Each component
313 is encoded as a single precision float.
314##
315
316#Const kLastEnum_SkColorType 11
Cary Clark682c58d2018-05-16 07:07:07 -0400317#NoJustify
318#Line # last valid value ##
319 Used by tests to iterate through all valid values.
320##
321
322#Const kN32_SkColorType 4 or 6
Cary Clark137b8742018-05-30 09:21:49 -0400323#Alias Native_Color_Type ##
Cary Clark682c58d2018-05-16 07:07:07 -0400324#NoJustify
Cary Clarkffb3d682018-05-17 12:17:28 -0400325#Line # native ARGB 32-bit encoding ##
326 Encodes ARGB as either kRGBA_8888_SkColorType or
Cary Clark682c58d2018-05-16 07:07:07 -0400327 kBGRA_8888_SkColorType, whichever is native to the platform.
Cary Clarkf895a422018-02-27 09:54:21 -0500328##
329
330#NoExample
331##
332
333#SeeAlso SkAlphaType SkColorSpace
334
335#Enum SkColorType ##
336
337#Subtopic Alpha_8
Cary Clark682c58d2018-05-16 07:07:07 -0400338#Line # encodes transparency only ##
339 Alpha pixels encode transparency without color information. Value of zero is
340 completely transparent; a value of 255 is completely opaque. Bitmap
341 pixels do not visibly draw, because its pixels have no color information.
342 When SkColorType is set to kAlpha_8_SkColorType, the paired SkAlphaType is
343 ignored.
Cary Clarkf895a422018-02-27 09:54:21 -0500344
Cary Clark682c58d2018-05-16 07:07:07 -0400345 #Example
346 #Description
347 Alpha pixels can modify another draw. orangePaint fills the bounds of bitmap,
348 with its transparency set to alpha8 pixel value.
349 ##
350 #Height 64
351 canvas->scale(16, 16);
352 SkBitmap bitmap;
353 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kAlpha_8_SkColorType, kOpaque_SkAlphaType);
354 bitmap.allocPixels(imageInfo);
355 SkCanvas offscreen(bitmap);
356 offscreen.clear(SK_ColorGREEN);
357 SkPaint orangePaint;
358 orangePaint.setARGB(0xFF, 0xFF, 0xA5, 0x00);
359 canvas->drawBitmap(bitmap, 0, 0, &orangePaint);
360 uint8_t alpha8[] = { 0xFF, 0xBB, 0x77, 0x33 };
361 SkPixmap alphaPixmap(imageInfo, &alpha8, imageInfo.minRowBytes());
362 if (bitmap.writePixels(alphaPixmap, 0, 0)) {
363 canvas->drawBitmap(bitmap, 2, 2, &orangePaint);
364 }
365 ##
Cary Clarkffb3d682018-05-17 12:17:28 -0400366 #SeeAlso Alpha Gray_8
Cary Clarkf895a422018-02-27 09:54:21 -0500367##
368
Cary Clark682c58d2018-05-16 07:07:07 -0400369#Subtopic RGB_565
Cary Clarkffb3d682018-05-17 12:17:28 -0400370#Line # encodes RGB in 16 bits ##
371 kRGB_565_SkColorType encodes RGB to fit in a 16-bit word. Red and blue
Cary Clark682c58d2018-05-16 07:07:07 -0400372 components use five bits describing 32 levels. Green components, more sensitive
373 to the eye, use six bits describing 64 levels. kRGB_565_SkColorType has no
374 bits for Alpha.
375
376 Pixels are fully opaque as if its Color_Alpha was set to one, and should
377 always be paired with kOpaque_SkAlphaType.
Cary Clarkf895a422018-02-27 09:54:21 -0500378
Cary Clark682c58d2018-05-16 07:07:07 -0400379 #Illustration
Cary Clarkf895a422018-02-27 09:54:21 -0500380
Cary Clark682c58d2018-05-16 07:07:07 -0400381 #Example
382 #Height 96
383 canvas->scale(16, 16);
384 SkBitmap bitmap;
385 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGB_565_SkColorType, kOpaque_SkAlphaType);
386 bitmap.allocPixels(imageInfo);
387 SkCanvas offscreen(bitmap);
388 offscreen.clear(SK_ColorGREEN);
389 canvas->drawBitmap(bitmap, 0, 0);
390 auto pack565 = [](unsigned r, unsigned g, unsigned b) -> uint16_t {
391 return (b << 0) | (g << 5) | (r << 11);
392 };
393 uint16_t red565[] = { pack565(0x1F, 0x00, 0x00), pack565(0x17, 0x00, 0x00),
394 pack565(0x0F, 0x00, 0x00), pack565(0x07, 0x00, 0x00) };
395 uint16_t blue565[] = { pack565(0x00, 0x00, 0x1F), pack565(0x00, 0x00, 0x17),
396 pack565(0x00, 0x00, 0x0F), pack565(0x00, 0x00, 0x07) };
397 SkPixmap redPixmap(imageInfo, &red565, imageInfo.minRowBytes());
398 if (bitmap.writePixels(redPixmap, 0, 0)) {
399 canvas->drawBitmap(bitmap, 2, 2);
400 }
401 SkPixmap bluePixmap(imageInfo, &blue565, imageInfo.minRowBytes());
402 if (bitmap.writePixels(bluePixmap, 0, 0)) {
403 canvas->drawBitmap(bitmap, 4, 4);
404 }
405 ##
Cary Clarkffb3d682018-05-17 12:17:28 -0400406 #SeeAlso ARGB_4444 RGBA_8888
Cary Clarkf895a422018-02-27 09:54:21 -0500407##
408
Cary Clark682c58d2018-05-16 07:07:07 -0400409#Subtopic ARGB_4444
Cary Clarkffb3d682018-05-17 12:17:28 -0400410#Line # encodes ARGB in 16 bits ##
411 kARGB_4444_SkColorType encodes ARGB to fit in 16-bit word. Each
Cary Clark682c58d2018-05-16 07:07:07 -0400412 component: alpha, blue, green, and red; use four bits, describing 16 levels.
413 Note that kARGB_4444_SkColorType is misnamed; the acronym does not
414 describe the actual component order.
Cary Clarkf895a422018-02-27 09:54:21 -0500415
Cary Clark682c58d2018-05-16 07:07:07 -0400416 #Illustration
Cary Clarkf895a422018-02-27 09:54:21 -0500417
Cary Clark682c58d2018-05-16 07:07:07 -0400418 If paired with kPremul_SkAlphaType: blue, green, and red components are
419 Premultiplied by the alpha value. If blue, green, or red is greater than alpha,
420 the drawn result is undefined.
Cary Clarkf895a422018-02-27 09:54:21 -0500421
Cary Clark682c58d2018-05-16 07:07:07 -0400422 If paired with kUnpremul_SkAlphaType: alpha, blue, green, and red components
Cary Clark77b3f3a2018-11-07 14:59:03 -0500423 may have any value. There may be a performance penalty with Unpremultiplied
Cary Clark682c58d2018-05-16 07:07:07 -0400424 pixels.
Cary Clarkf895a422018-02-27 09:54:21 -0500425
Cary Clark682c58d2018-05-16 07:07:07 -0400426 If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum;
427 blue, green, and red components are fully opaque. If any alpha component is
428 less than 15, the drawn result is undefined.
Cary Clarkf895a422018-02-27 09:54:21 -0500429
Cary Clark682c58d2018-05-16 07:07:07 -0400430 #Bug 7648
Cary Clarkf895a422018-02-27 09:54:21 -0500431
Cary Clark682c58d2018-05-16 07:07:07 -0400432 #Example
433 #Height 96
434 canvas->scale(16, 16);
435 SkBitmap bitmap;
436 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kARGB_4444_SkColorType, kPremul_SkAlphaType);
437 bitmap.allocPixels(imageInfo);
438 SkCanvas offscreen(bitmap);
439 offscreen.clear(SK_ColorGREEN);
440 canvas->drawBitmap(bitmap, 0, 0);
441 auto pack4444 = [](unsigned a, unsigned r, unsigned g, unsigned b) -> uint16_t {
442 return (a << 0) | (b << 4) | (g << 8) | (r << 12);
443 };
444 uint16_t red4444[] = { pack4444(0xF, 0xF, 0x0, 0x0), pack4444(0xF, 0xb, 0x0, 0x0),
445 pack4444(0xF, 0x7, 0x0, 0x0), pack4444(0xF, 0x3, 0x0, 0x0) };
446 uint16_t blue4444[] = { pack4444(0xF, 0x0, 0x0, 0xF), pack4444(0xF, 0x0, 0x0, 0xb),
447 pack4444(0xF, 0x0, 0x0, 0x7), pack4444(0xF, 0x0, 0x0, 0x3) };
448 SkPixmap redPixmap(imageInfo, &red4444, imageInfo.minRowBytes());
449 if (bitmap.writePixels(redPixmap, 0, 0)) {
450 canvas->drawBitmap(bitmap, 2, 2);
451 }
452 SkPixmap bluePixmap(imageInfo, &blue4444, imageInfo.minRowBytes());
453 if (bitmap.writePixels(bluePixmap, 0, 0)) {
454 canvas->drawBitmap(bitmap, 4, 4);
455 }
456 ##
Cary Clarkffb3d682018-05-17 12:17:28 -0400457 #SeeAlso RGBA_8888
Cary Clarkf895a422018-02-27 09:54:21 -0500458##
459
460#Subtopic RGBA_8888
Cary Clarkffb3d682018-05-17 12:17:28 -0400461#Line # encodes ARGB Big_Endian in 32 bits ##
462 kRGBA_8888_SkColorType encodes ARGB into a 32-bit word. Each component:
Cary Clark682c58d2018-05-16 07:07:07 -0400463 red, green, blue, alpha; use eight bits, describing 256 levels.
Cary Clarkf895a422018-02-27 09:54:21 -0500464
Cary Clark682c58d2018-05-16 07:07:07 -0400465 #Illustration
Cary Clarkf895a422018-02-27 09:54:21 -0500466
Cary Clark682c58d2018-05-16 07:07:07 -0400467 If paired with kPremul_SkAlphaType: red, green, and blue components are
468 Premultiplied by the alpha value. If red, green, or blue is greater than alpha,
469 the drawn result is undefined.
Cary Clarkf895a422018-02-27 09:54:21 -0500470
Cary Clark682c58d2018-05-16 07:07:07 -0400471 If paired with kUnpremul_SkAlphaType: alpha, red, green, and blue components
Cary Clark77b3f3a2018-11-07 14:59:03 -0500472 may have any value. There may be a performance penalty with Unpremultiplied
Cary Clark682c58d2018-05-16 07:07:07 -0400473 pixels.
Cary Clarkf895a422018-02-27 09:54:21 -0500474
Cary Clark682c58d2018-05-16 07:07:07 -0400475 If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum;
476 red, green, and blue components are fully opaque. If any alpha component is
477 less than 255, the drawn result is undefined.
Cary Clarkf895a422018-02-27 09:54:21 -0500478
Cary Clark682c58d2018-05-16 07:07:07 -0400479 On Big_Endian platforms, kRGBA_8888_SkColorType is the native Color_Type, and
480 will have the best performance. Use kN32_SkColorType to choose the best
481 Color_Type for the platform at compile time.
Cary Clarkf895a422018-02-27 09:54:21 -0500482
Cary Clark682c58d2018-05-16 07:07:07 -0400483 #Example
484 #Height 96
485 canvas->scale(16, 16);
486 SkBitmap bitmap;
487 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGBA_8888_SkColorType, kPremul_SkAlphaType);
488 bitmap.allocPixels(imageInfo);
489 SkCanvas offscreen(bitmap);
490 offscreen.clear(SK_ColorGREEN);
491 canvas->drawBitmap(bitmap, 0, 0);
492 auto pack8888 = [](unsigned a, unsigned r, unsigned g, unsigned b) -> uint32_t {
493 return (r << 0) | (g << 8) | (b << 16) | (a << 24);
494 };
495 uint32_t red8888[] = { pack8888(0xFF, 0xFF, 0x0, 0x0), pack8888(0xFF, 0xbb, 0x0, 0x0),
496 pack8888(0xFF, 0x77, 0x0, 0x0), pack8888(0xFF, 0x33, 0x0, 0x0) };
497 uint32_t blue8888[] = { pack8888(0xFF, 0x0, 0x0, 0x0FF), pack8888(0xFF, 0x0, 0x0, 0x0bb),
498 pack8888(0xFF, 0x0, 0x0, 0x077), pack8888(0xFF, 0x0, 0x0, 0x033) };
499 SkPixmap redPixmap(imageInfo, &red8888, imageInfo.minRowBytes());
500 if (bitmap.writePixels(redPixmap, 0, 0)) {
501 canvas->drawBitmap(bitmap, 2, 2);
502 }
503 SkPixmap bluePixmap(imageInfo, &blue8888, imageInfo.minRowBytes());
504 if (bitmap.writePixels(bluePixmap, 0, 0)) {
505 canvas->drawBitmap(bitmap, 4, 4);
506 }
507 ##
Cary Clarkffb3d682018-05-17 12:17:28 -0400508 #SeeAlso RGB_888 BGRA_8888
Cary Clarkf895a422018-02-27 09:54:21 -0500509##
510
Cary Clark682c58d2018-05-16 07:07:07 -0400511#Subtopic RGB_888
Cary Clarkffb3d682018-05-17 12:17:28 -0400512#Line # encodes RGB in 32 bits ##
513 kRGB_888x_SkColorType encodes RGB into a 32-bit word. Each component:
Cary Clark682c58d2018-05-16 07:07:07 -0400514 red, green, blue; use eight bits, describing 256 levels. Eight bits are
515 unused. Pixels described by kRGB_888x_SkColorType are fully opaque as if
516 their Color_Alpha was set to one, and should always be paired with
517 kOpaque_SkAlphaType.
Cary Clarkf895a422018-02-27 09:54:21 -0500518
Cary Clark682c58d2018-05-16 07:07:07 -0400519 #Illustration
Cary Clarkf895a422018-02-27 09:54:21 -0500520
Cary Clark682c58d2018-05-16 07:07:07 -0400521 #Example
522 #Bug 7645
523 #Height 96
524 #Platform cpu
525 canvas->scale(16, 16);
526 SkBitmap bitmap;
527 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGB_888x_SkColorType, kOpaque_SkAlphaType);
528 bitmap.allocPixels(imageInfo);
529 SkCanvas offscreen(bitmap);
530 offscreen.clear(SK_ColorGREEN);
531 canvas->drawBitmap(bitmap, 0, 0);
532 auto pack888 = [](unsigned r, unsigned g, unsigned b) -> uint32_t {
533 return (r << 0) | (g << 8) | (b << 16);
534 };
535 uint32_t red888[] = { pack888(0xFF, 0x00, 0x00), pack888(0xbb, 0x00, 0x00),
536 pack888(0x77, 0x00, 0x00), pack888(0x33, 0x00, 0x00) };
537 uint32_t blue888[] = { pack888(0x00, 0x00, 0xFF), pack888(0x00, 0x00, 0xbb),
538 pack888(0x00, 0x00, 0x77), pack888(0x00, 0x00, 0x33) };
539 if (bitmap.installPixels(imageInfo, (void*) red888, imageInfo.minRowBytes())) {
540 canvas->drawBitmap(bitmap, 2, 2);
541 }
542 if (bitmap.installPixels(imageInfo, (void*) blue888, imageInfo.minRowBytes())) {
543 canvas->drawBitmap(bitmap, 4, 4);
544 }
545 ##
Cary Clarkffb3d682018-05-17 12:17:28 -0400546 #SeeAlso RGBA_8888 BGRA_8888
Cary Clarkf895a422018-02-27 09:54:21 -0500547##
548
549#Subtopic BGRA_8888
Cary Clarkffb3d682018-05-17 12:17:28 -0400550#Line # encodes ARGB Little_Endian in 32 bits ##
551 kBGRA_8888_SkColorType encodes ARGB into a 32-bit word. Each component:
Cary Clark682c58d2018-05-16 07:07:07 -0400552 blue, green, red, and alpha; use eight bits, describing 256 levels.
Cary Clarkf895a422018-02-27 09:54:21 -0500553
Cary Clark682c58d2018-05-16 07:07:07 -0400554 #Illustration
Cary Clarkf895a422018-02-27 09:54:21 -0500555
Cary Clark682c58d2018-05-16 07:07:07 -0400556 If paired with kPremul_SkAlphaType: blue, green, and red components are
557 Premultiplied by the alpha value. If blue, green, or red is greater than alpha,
558 the drawn result is undefined.
Cary Clarkf895a422018-02-27 09:54:21 -0500559
Cary Clark682c58d2018-05-16 07:07:07 -0400560 If paired with kUnpremul_SkAlphaType: blue, green, red, and alpha components
561 may have any value. There may be a performance penalty with Unpremultiplied
562 pixels.
Cary Clarkf895a422018-02-27 09:54:21 -0500563
Cary Clark682c58d2018-05-16 07:07:07 -0400564 If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum;
565 blue, green, and red components are fully opaque. If any alpha component is
566 less than 255, the drawn result is undefined.
Cary Clarkf895a422018-02-27 09:54:21 -0500567
Cary Clark682c58d2018-05-16 07:07:07 -0400568 On Little_Endian platforms, kBGRA_8888_SkColorType is the native Color_Type,
569 and will have the best performance. Use kN32_SkColorType to choose the best
570 Color_Type for the platform at compile time.
Cary Clarkf895a422018-02-27 09:54:21 -0500571
Cary Clark682c58d2018-05-16 07:07:07 -0400572 #Example
573 #Height 96
574 canvas->scale(16, 16);
575 SkBitmap bitmap;
576 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kBGRA_8888_SkColorType, kPremul_SkAlphaType);
577 bitmap.allocPixels(imageInfo);
578 SkCanvas offscreen(bitmap);
579 offscreen.clear(SK_ColorGREEN);
580 canvas->drawBitmap(bitmap, 0, 0);
581 auto pack8888 = [](unsigned a, unsigned r, unsigned g, unsigned b) -> uint32_t {
582 return (b << 0) | (g << 8) | (r << 16) | (a << 24);
583 };
584 uint32_t red8888[] = { pack8888(0xFF, 0xFF, 0x0, 0x0), pack8888(0xFF, 0xbb, 0x0, 0x0),
585 pack8888(0xFF, 0x99, 0x0, 0x0), pack8888(0xFF, 0x55, 0x0, 0x0) };
586 uint32_t blue8888[] = { pack8888(0xFF, 0x0, 0x0, 0x0FF), pack8888(0xFF, 0x0, 0x0, 0x0bb),
587 pack8888(0xFF, 0x0, 0x0, 0x099), pack8888(0xFF, 0x0, 0x0, 0x055) };
588 SkPixmap redPixmap(imageInfo, &red8888, imageInfo.minRowBytes());
589 if (bitmap.writePixels(redPixmap, 0, 0)) {
590 canvas->drawBitmap(bitmap, 2, 2);
591 }
592 SkPixmap bluePixmap(imageInfo, &blue8888, imageInfo.minRowBytes());
593 if (bitmap.writePixels(bluePixmap, 0, 0)) {
594 canvas->drawBitmap(bitmap, 4, 4);
595 }
596 ##
597 #SeeAlso RGBA_8888
Cary Clarkf895a422018-02-27 09:54:21 -0500598##
599
600#Subtopic RGBA_1010102
Cary Clarkffb3d682018-05-17 12:17:28 -0400601#Line # encodes ARGB ten bits per color component ##
602 kRGBA_1010102_SkColorType encodes ARGB into a 32-bit word. Each
Cary Clark682c58d2018-05-16 07:07:07 -0400603 Color component: red, green, and blue; use ten bits, describing 1024 levels.
604 Two bits contain alpha, describing four levels. Possible alpha
605 values are zero: fully transparent; one: 33% opaque; two: 67% opaque;
606 three: fully opaque.
Cary Clarkf895a422018-02-27 09:54:21 -0500607
Cary Clark682c58d2018-05-16 07:07:07 -0400608 At present, Color in Paint does not provide enough precision to
609 draw all colors possible to a kRGBA_1010102_SkColorType Surface.
Cary Clarkf895a422018-02-27 09:54:21 -0500610
Cary Clark682c58d2018-05-16 07:07:07 -0400611 #Illustration
Cary Clarkf895a422018-02-27 09:54:21 -0500612
Cary Clark682c58d2018-05-16 07:07:07 -0400613 If paired with kPremul_SkAlphaType: red, green, and blue components are
614 Premultiplied by the alpha value. If red, green, or blue is greater than the
615 alpha replicated to ten bits, the drawn result is undefined.
Cary Clarkf895a422018-02-27 09:54:21 -0500616
Cary Clark682c58d2018-05-16 07:07:07 -0400617 If paired with kUnpremul_SkAlphaType: alpha, red, green, and blue components
618 may have any value. There may be a performance penalty with Unpremultiplied
619 pixels.
Cary Clarkf895a422018-02-27 09:54:21 -0500620
Cary Clark682c58d2018-05-16 07:07:07 -0400621 If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum;
622 red, green, and blue components are fully opaque. If any alpha component is
623 less than three, the drawn result is undefined.
Cary Clarkf895a422018-02-27 09:54:21 -0500624
Cary Clark682c58d2018-05-16 07:07:07 -0400625 #Example
626 #Bug 7645
627 #Height 96
628 #Platform cpu
629 canvas->scale(16, 16);
630 SkBitmap bitmap;
631 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGBA_1010102_SkColorType, kOpaque_SkAlphaType);
632 bitmap.allocPixels(imageInfo);
633 SkCanvas offscreen(bitmap);
634 offscreen.clear(SK_ColorGREEN);
635 canvas->drawBitmap(bitmap, 0, 0);
636 auto pack1010102 = [](unsigned r, unsigned g, unsigned b, unsigned a) -> uint32_t {
637 return (r << 0) | (g << 10) | (b << 20) | (a << 30);
638 };
639 uint32_t redBits[] = { pack1010102(0x3FF, 0x000, 0x000, 0x3),
640 pack1010102(0x2ff, 0x000, 0x000, 0x3),
641 pack1010102(0x1ff, 0x000, 0x000, 0x3),
642 pack1010102(0x0ff, 0x000, 0x000, 0x3) };
643 uint32_t blueBits[] = { pack1010102(0x000, 0x000, 0x3FF, 0x3),
644 pack1010102(0x000, 0x000, 0x2ff, 0x3),
645 pack1010102(0x000, 0x000, 0x1ff, 0x3),
646 pack1010102(0x000, 0x000, 0x0ff, 0x3) };
647 if (bitmap.installPixels(imageInfo, (void*) redBits, imageInfo.minRowBytes())) {
648 canvas->drawBitmap(bitmap, 2, 2);
649 }
650 SkPixmap bluePixmap(imageInfo, &blueBits, imageInfo.minRowBytes());
651 if (bitmap.installPixels(imageInfo, (void*) blueBits, imageInfo.minRowBytes())) {
652 canvas->drawBitmap(bitmap, 4, 4);
653 }
654 ##
Cary Clarkffb3d682018-05-17 12:17:28 -0400655 #SeeAlso RGB_101010 RGBA_8888
Cary Clarkf895a422018-02-27 09:54:21 -0500656##
657
Cary Clark682c58d2018-05-16 07:07:07 -0400658#Subtopic RGB_101010
Cary Clarkffb3d682018-05-17 12:17:28 -0400659#Line # encodes RGB ten bits per color component ##
660 kRGB_101010x_SkColorType encodes RGB into a 32-bit word. Each
Cary Clark682c58d2018-05-16 07:07:07 -0400661 Color component: red, green, and blue; use ten bits, describing 1024 levels.
662 Two bits are unused. Pixels described by kRGB_101010x_SkColorType are fully
663 opaque as if its Color_Alpha was set to one, and should always be paired
664 with kOpaque_SkAlphaType.
Cary Clarkf895a422018-02-27 09:54:21 -0500665
Cary Clark682c58d2018-05-16 07:07:07 -0400666 At present, Color in Paint does not provide enough precision to
667 draw all colors possible to a kRGB_101010x_SkColorType Surface.
Cary Clark681287e2018-03-16 11:34:15 -0400668
Cary Clark682c58d2018-05-16 07:07:07 -0400669 #Illustration
Cary Clarkf895a422018-02-27 09:54:21 -0500670
Cary Clark682c58d2018-05-16 07:07:07 -0400671 #Example
672 #Bug 7645
673 #Height 96
674 #Platform cpu
675 canvas->scale(16, 16);
676 SkBitmap bitmap;
677 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGB_101010x_SkColorType, kOpaque_SkAlphaType);
678 bitmap.allocPixels(imageInfo);
679 SkCanvas offscreen(bitmap);
680 offscreen.clear(SK_ColorGREEN);
681 canvas->drawBitmap(bitmap, 0, 0);
682 auto pack101010x = [](unsigned r, unsigned g, unsigned b) -> uint32_t {
683 return (r << 0) | (g << 10) | (b << 20);
684 };
685 uint32_t redBits[] = { pack101010x(0x3FF, 0x000, 0x000), pack101010x(0x2ff, 0x000, 0x000),
686 pack101010x(0x1ff, 0x000, 0x000), pack101010x(0x0ff, 0x000, 0x000) };
687 uint32_t blueBits[] = { pack101010x(0x000, 0x000, 0x3FF), pack101010x(0x000, 0x000, 0x2ff),
688 pack101010x(0x000, 0x000, 0x1ff), pack101010x(0x000, 0x000, 0x0ff) };
689 if (bitmap.installPixels(imageInfo, (void*) redBits, imageInfo.minRowBytes())) {
690 canvas->drawBitmap(bitmap, 2, 2);
691 }
692 SkPixmap bluePixmap(imageInfo, &blueBits, imageInfo.minRowBytes());
693 if (bitmap.installPixels(imageInfo, (void*) blueBits, imageInfo.minRowBytes())) {
694 canvas->drawBitmap(bitmap, 4, 4);
695 }
696 ##
Cary Clarkffb3d682018-05-17 12:17:28 -0400697 #SeeAlso RGBA_1010102
Cary Clarkf895a422018-02-27 09:54:21 -0500698##
699
700#Subtopic Gray_8
Cary Clark09d80c02018-10-31 12:14:03 -0400701#Line # encodes level of grayscale in 8 bits ##
702 kGray_8_SkColorType encodes grayscale level in eight bits that is equivalent
Cary Clark682c58d2018-05-16 07:07:07 -0400703 to equal values for red, blue, and green, representing colors from black to
704 white. Pixels described by kGray_8_SkColorType are fully
705 opaque as if its Color_Alpha was set to one, and should always be paired with
706 kOpaque_SkAlphaType.
Cary Clarkf895a422018-02-27 09:54:21 -0500707
Cary Clark682c58d2018-05-16 07:07:07 -0400708 #Example
709 #Height 64
710 canvas->scale(16, 16);
711 SkBitmap bitmap;
712 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kGray_8_SkColorType, kOpaque_SkAlphaType);
713 bitmap.allocPixels(imageInfo);
714 SkCanvas offscreen(bitmap);
715 offscreen.clear(SK_ColorGREEN);
716 canvas->drawBitmap(bitmap, 0, 0);
717 uint8_t gray8[] = { 0xFF, 0xBB, 0x77, 0x33 };
718 SkPixmap grayPixmap(imageInfo, &gray8, imageInfo.minRowBytes());
719 if (bitmap.writePixels(grayPixmap, 0, 0)) {
720 canvas->drawBitmap(bitmap, 2, 2);
721 }
722 ##
Cary Clarkffb3d682018-05-17 12:17:28 -0400723 #SeeAlso Alpha_8
Cary Clarkf895a422018-02-27 09:54:21 -0500724##
725
726#Subtopic RGBA_F16
Cary Clarkffb3d682018-05-17 12:17:28 -0400727#Line # encodes ARGB as half floats ##
728 kRGBA_F16_SkColorType encodes ARGB into a 64-bit word. Each component:
Cary Clark224c7002018-06-27 11:00:21 -0400729 blue, green, red, and alpha; use 16 bits, describing a floating point value,
Cary Clark929e4362018-06-19 09:07:28 -0400730 from -65500 to 65000 with 3.31 decimal digits of precision.
Cary Clarkf895a422018-02-27 09:54:21 -0500731
Cary Clark682c58d2018-05-16 07:07:07 -0400732 At present, Color in Paint does not provide enough precision or range to
733 draw all colors possible to a kRGBA_F16_SkColorType Surface.
Cary Clark681287e2018-03-16 11:34:15 -0400734
Cary Clark682c58d2018-05-16 07:07:07 -0400735 Each component encodes a floating point value using
736 #A Half floats # https://www.khronos.org/opengl/wiki/Small_Float_Formats ##
737 . Meaningful colors are represented by the range 0.0 to 1.0, although smaller
738 and larger values may be useful when used in combination with Transfer_Mode.
Cary Clark681287e2018-03-16 11:34:15 -0400739
Cary Clark682c58d2018-05-16 07:07:07 -0400740 #Illustration
Cary Clarkf895a422018-02-27 09:54:21 -0500741
Cary Clark682c58d2018-05-16 07:07:07 -0400742 If paired with kPremul_SkAlphaType: blue, green, and red components are
743 Premultiplied by the alpha value. If blue, green, or red is greater than alpha,
744 the drawn result is undefined.
Cary Clark681287e2018-03-16 11:34:15 -0400745
Cary Clark682c58d2018-05-16 07:07:07 -0400746 If paired with kUnpremul_SkAlphaType: blue, green, red, and alpha components
747 may have any value. There may be a performance penalty with Unpremultiplied
748 pixels.
Cary Clark681287e2018-03-16 11:34:15 -0400749
Cary Clark682c58d2018-05-16 07:07:07 -0400750 If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum;
751 blue, green, and red components are fully opaque. If any alpha component is
Cary Clark224c7002018-06-27 11:00:21 -0400752 less than one, the drawn result is undefined.
Cary Clark681287e2018-03-16 11:34:15 -0400753
Cary Clark682c58d2018-05-16 07:07:07 -0400754 #ToDo
755 FloatToHalf should be replaced with SkFloatToHalf if/when that's made public
756 ##
Cary Clark2dc84ad2018-01-26 12:56:22 -0500757
Cary Clark682c58d2018-05-16 07:07:07 -0400758 #Example
759 #Height 96
760 #Function
761 union FloatUIntUnion {
762 uint32_t fUInt;
763 float fFloat;
Cary Clarkf895a422018-02-27 09:54:21 -0500764 };
Cary Clark682c58d2018-05-16 07:07:07 -0400765
766 uint16_t FloatToHalf(float f) {
767 static const FloatUIntUnion magic = { 15 << 23 };
768 static const uint32_t round_mask = ~0xfffu;
769 FloatUIntUnion floatUnion;
770 floatUnion.fFloat = f;
771 uint32_t sign = floatUnion.fUInt & 0x80000000u;
772 floatUnion.fUInt ^= sign;
773 floatUnion.fUInt &= round_mask;
774 floatUnion.fFloat *= magic.fFloat;
775 floatUnion.fUInt -= round_mask;
776 return (floatUnion.fUInt >> 13) | (sign >> 16);
Cary Clarkf895a422018-02-27 09:54:21 -0500777 }
Cary Clark682c58d2018-05-16 07:07:07 -0400778 ##
779
780 void draw(SkCanvas* canvas) {
781 canvas->scale(16, 16);
782 SkBitmap bitmap;
783 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGBA_F16_SkColorType, kPremul_SkAlphaType);
784 bitmap.allocPixels(imageInfo);
785 SkCanvas offscreen(bitmap);
786 offscreen.clear(SK_ColorGREEN);
787 canvas->drawBitmap(bitmap, 0, 0);
788 auto H = [](float c) -> uint16_t {
789 return FloatToHalf(c);
790 };
791 // R G B A
Cary Clark224c7002018-06-27 11:00:21 -0400792 uint16_t red_f16[][4] = { { H(1.0), H(0.0), H(0.0), H(1.0) },
793 { H(.75), H(0.0), H(0.0), H(1.0) },
794 { H(.50), H(0.0), H(0.0), H(1.0) },
795 { H(.25), H(0.0), H(0.0), H(1.0) } };
796 uint16_t blue_f16[][4] = { { H(0.0), H(0.0), H(1.0), H(1.0) },
797 { H(0.0), H(0.0), H(.75), H(1.0) },
798 { H(0.0), H(0.0), H(.50), H(1.0) },
799 { H(0.0), H(0.0), H(.25), H(1.0) } };
Cary Clark682c58d2018-05-16 07:07:07 -0400800 SkPixmap redPixmap(imageInfo, red_f16, imageInfo.minRowBytes());
801 if (bitmap.writePixels(redPixmap, 0, 0)) {
802 canvas->drawBitmap(bitmap, 2, 2);
803 }
804 SkPixmap bluePixmap(imageInfo, blue_f16, imageInfo.minRowBytes());
805 if (bitmap.writePixels(bluePixmap, 0, 0)) {
806 canvas->drawBitmap(bitmap, 4, 4);
807 }
Cary Clarkf895a422018-02-27 09:54:21 -0500808 }
Cary Clark682c58d2018-05-16 07:07:07 -0400809 ##
Cary Clarkffb3d682018-05-17 12:17:28 -0400810 #SeeAlso SkColor4f
Cary Clarkf895a422018-02-27 09:54:21 -0500811##
Cary Clark2dc84ad2018-01-26 12:56:22 -0500812
Cary Clark224c7002018-06-27 11:00:21 -0400813#Subtopic RGBA_F32
814#Line # encodes ARGB as single precision floats ##
815 kRGBA_F32_SkColorType encodes ARGB into a 128-bit word. Each component:
816 blue, green, red, and alpha; use 32 bits, describing a floating point value,
817 from -3.402823e+38 to 3.402823e+38 with 7.225 decimal digits of precision.
818
819 At present, Color in Paint does not provide enough precision or range to
820 draw all colors possible to a kRGBA_F32_SkColorType Surface.
821
822 Each component encodes a floating point value using
823 #A single-precision floats # https://en.wikipedia.org/wiki/Single-precision_floating-point_format ##
824 . Meaningful colors are represented by the range 0.0 to 1.0, although smaller
825 and larger values may be useful when used in combination with Transfer_Mode.
826
827 #Illustration
828
829 If paired with kPremul_SkAlphaType: blue, green, and red components are
830 Premultiplied by the alpha value. If blue, green, or red is greater than alpha,
831 the drawn result is undefined.
832
833 If paired with kUnpremul_SkAlphaType: blue, green, red, and alpha components
834 may have any value. There may be a performance penalty with Unpremultiplied
835 pixels.
836
837 If paired with kOpaque_SkAlphaType: all alpha component values are at the maximum;
838 blue, green, and red components are fully opaque. If any alpha component is
839 less than one, the drawn result is undefined.
840
841 #NoExample
Cary Clark61313f32018-10-08 14:57:48 -0400842 canvas->scale(16, 16);
843 SkBitmap bitmap;
844 SkImageInfo imageInfo = SkImageInfo::Make(2, 2, kRGBA_F32_SkColorType, kPremul_SkAlphaType);
845 bitmap.allocPixels(imageInfo);
846 SkCanvas offscreen(bitmap);
847 offscreen.clear(SK_ColorGREEN);
848 canvas->drawBitmap(bitmap, 0, 0);
849 // R G B A
850 float red_f32[][4] = { { 1.0, 0.0, 0.0, 1.0 },
851 { .75, 0.0, 0.0, 1.0 },
852 { .50, 0.0, 0.0, 1.0 },
853 { .25, 0.0, 0.0, 1.0 } };
854 float blue_f32[][4] = { { 0.0, 0.0, 1.0, 1.0 },
855 { 0.0, 0.0, .75, 1.0 },
856 { 0.0, 0.0, .50, 1.0 },
857 { 0.0, 0.0, .25, 1.0 } };
858 SkPixmap redPixmap(imageInfo, red_f32, imageInfo.minRowBytes());
859 if (bitmap.writePixels(redPixmap, 0, 0)) {
860 canvas->drawBitmap(bitmap, 2, 2);
861 }
862 SkPixmap bluePixmap(imageInfo, blue_f32, imageInfo.minRowBytes());
863 if (bitmap.writePixels(bluePixmap, 0, 0)) {
864 canvas->drawBitmap(bitmap, 4, 4);
Cary Clark224c7002018-06-27 11:00:21 -0400865 }
866 ##
867 #SeeAlso SkColor4f
868##
869
870
Cary Clark08895c42018-02-01 09:37:32 -0500871#Subtopic Color_Type ##
Cary Clark2dc84ad2018-01-26 12:56:22 -0500872
873# ------------------------------------------------------------------------------
Cary Clark681287e2018-03-16 11:34:15 -0400874
875#Method int SkColorTypeBytesPerPixel(SkColorType ct)
876#In Property
877#Line # returns Color_Type byte size ##
Cary Clark09d80c02018-10-31 12:14:03 -0400878#Populate
Cary Clark681287e2018-03-16 11:34:15 -0400879
880#Example
881#Height 192
882 const char* colors[] = { "Unknown", "Alpha_8", "RGB_565", "ARGB_4444", "RGBA_8888", "RGB_888x",
883 "BGRA_8888", "RGBA_1010102", "RGB_101010x", "Gray_8", "RGBA_F16" };
884 SkPaint paint;
Mike Reed729bb192019-02-13 16:56:13 -0500885 SkFont font(SkTypeface::MakeFromName("monospace", SkFontStyle()), 10);
Cary Clark681287e2018-03-16 11:34:15 -0400886 int y = 15;
887 canvas->drawString(" colorType bytes", 10, y, paint);
888 for (SkColorType colorType : { #list_of_color_types#
889 } ) {
890 int result = SkColorTypeBytesPerPixel(colorType);
891 SkString string;
892 string.printf("%13s %4d", colors[(int) colorType], result);
Mike Reed729bb192019-02-13 16:56:13 -0500893 canvas->drawString(string, 10, y += 14, font, paint);
Cary Clark681287e2018-03-16 11:34:15 -0400894 }
895##
896#SeeAlso SkImageInfo::bytesPerPixel
897##
898
899# ------------------------------------------------------------------------------
900
901#Method bool SkColorTypeIsAlwaysOpaque(SkColorType ct)
902#In Property
903#Line # returns if Color_Type includes Color_Alpha ##
Cary Clark09d80c02018-10-31 12:14:03 -0400904#Populate
Cary Clark681287e2018-03-16 11:34:15 -0400905
906#Example
907#Height 192
908 const char* colors[] = { "Unknown", "Alpha_8", "RGB_565", "ARGB_4444", "RGBA_8888", "RGB_888x",
909 "BGRA_8888", "RGBA_1010102", "RGB_101010x", "Gray_8", "RGBA_F16" };
910 SkPaint paint;
Mike Reed729bb192019-02-13 16:56:13 -0500911 SkFont font(SkTypeface::MakeFromName("monospace", SkFontStyle()), 10);
Cary Clark681287e2018-03-16 11:34:15 -0400912 int y = 15;
913 canvas->drawString(" colorType bytes", 10, y, paint);
914 for (SkColorType colorType : { #list_of_color_types#
915 } ) {
916 bool result = SkColorTypeIsAlwaysOpaque(colorType);
917 SkString string;
918 string.printf("%13s %6s", colors[(int) colorType], result ? "true" : "false");
Mike Reed729bb192019-02-13 16:56:13 -0500919 canvas->drawString(string, 10, y += 14, font, paint);
Cary Clark681287e2018-03-16 11:34:15 -0400920 }
921##
922#SeeAlso SkColorTypeValidateAlphaType
923##
924
925# ------------------------------------------------------------------------------
926
927#Method bool SkColorTypeValidateAlphaType(SkColorType colorType, SkAlphaType alphaType,
928 SkAlphaType* canonical = nullptr)
929#In Property
930#Line # returns if Alpha_Type is valid ##
Cary Clark09d80c02018-10-31 12:14:03 -0400931#Populate
Cary Clark681287e2018-03-16 11:34:15 -0400932
933#Example
934#Height 640
935 const char* colors[] = { "Unknown", "Alpha_8", "RGB_565", "ARGB_4444", "RGBA_8888", "RGB_888x",
936 "BGRA_8888", "RGBA_1010102", "RGB_101010x", "Gray_8", "RGBA_F16" };
937 const char* alphas[] = {"Unknown ", "Opaque ", "Premul ", "Unpremul"};
938 SkAlphaType alphaTypes[] = { #list_of_alpha_types#
939 };
940 SkPaint paint;
Mike Reed729bb192019-02-13 16:56:13 -0500941 SkFont font(SkTypeface::MakeFromName("monospace", SkFontStyle()), 10);
Cary Clark681287e2018-03-16 11:34:15 -0400942 int y = 15;
943 canvas->drawString(" colorType alphaType canonical", 10, y, paint);
944 for (SkColorType colorType : { #list_of_color_types#
945 } ) {
946 for (SkAlphaType alphaType : alphaTypes) {
947 SkAlphaType canonicalAlphaType = kUnknown_SkAlphaType;
948 bool result = SkColorTypeValidateAlphaType(colorType, alphaType, &canonicalAlphaType);
949 SkString string;
950 string.printf("%13s %10s %10s", colors[(int) colorType], alphas[(int) alphaType],
951 result ? alphas[(int) canonicalAlphaType] : "------ ");
952 canvas->drawString(string, 10, y += 14, paint);
953 }
954 }
955##
956#SeeAlso SkColorTypeIsAlwaysOpaque
957##
958
959# ------------------------------------------------------------------------------
Cary Clark772953472018-02-12 09:38:08 -0500960#Subtopic YUV_ColorSpace
Cary Clark682c58d2018-05-16 07:07:07 -0400961#Line # color range of YUV pixels ##
Cary Clark137b8742018-05-30 09:21:49 -0400962#Alias YUV_ColorSpace ##
963
Cary Clark2dc84ad2018-01-26 12:56:22 -0500964#Enum SkYUVColorSpace
Cary Clark06c20f32018-03-20 15:53:27 -0400965#Line # color range of YUV pixels ##
Cary Clark2dc84ad2018-01-26 12:56:22 -0500966
967#Code
Cary Clark61313f32018-10-08 14:57:48 -0400968#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -0500969##
970
Cary Clark06c20f32018-03-20 15:53:27 -0400971Describes color range of YUV pixels. The color mapping from YUV to RGB varies
972depending on the source. YUV pixels may be generated by JPEG images, standard
973video streams, or high definition video streams. Each has its own mapping from
974YUV and RGB.
975
976JPEG YUV values encode the full range of 0 to 255 for all three components.
977Video YUV values range from 16 to 235 for all three components. Details of
Cary Clark682c58d2018-05-16 07:07:07 -0400978encoding and conversion to RGB are described in
Cary Clark06c20f32018-03-20 15:53:27 -0400979#A YCbCr color space # https://en.wikipedia.org/wiki/YCbCr ##
980.
Cary Clark2dc84ad2018-01-26 12:56:22 -0500981
982#Const kJPEG_SkYUVColorSpace 0
Cary Clark682c58d2018-05-16 07:07:07 -0400983#Line # describes full range ##
984Describes standard JPEG color space;
Cary Clark06c20f32018-03-20 15:53:27 -0400985#A CCIR 601 # https://en.wikipedia.org/wiki/Rec._601 ##
986with full range of 0 to 255 for components.
Cary Clark2dc84ad2018-01-26 12:56:22 -0500987##
988#Const kRec601_SkYUVColorSpace 1
Cary Clark682c58d2018-05-16 07:07:07 -0400989#Line # describes SDTV range ##
990Describes standard used by standard definition television;
Cary Clark06c20f32018-03-20 15:53:27 -0400991#A CCIR 601 # https://en.wikipedia.org/wiki/Rec._601 ##
992with studio range of 16 to 235 range for components.
Cary Clark2dc84ad2018-01-26 12:56:22 -0500993##
994#Const kRec709_SkYUVColorSpace 2
Cary Clark682c58d2018-05-16 07:07:07 -0400995#Line # describes HDTV range ##
996Describes standard used by high definition television;
997#A Rec. 709 # https://en.wikipedia.org/wiki/Rec._709 ##
Cary Clark06c20f32018-03-20 15:53:27 -0400998with studio range of 16 to 235 range for components.
Cary Clark2dc84ad2018-01-26 12:56:22 -0500999##
Cary Clark682c58d2018-05-16 07:07:07 -04001000#Const kLastEnum_SkYUVColorSpace 2
1001#Line # last valid value ##
1002 Used by tests to iterate through all valid values.
1003##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001004
Cary Clark06c20f32018-03-20 15:53:27 -04001005#NoExample
Cary Clark2dc84ad2018-01-26 12:56:22 -05001006##
1007
Cary Clark06c20f32018-03-20 15:53:27 -04001008#SeeAlso SkImage::MakeFromYUVTexturesCopy SkImage::MakeFromNV12TexturesCopy
Cary Clark2dc84ad2018-01-26 12:56:22 -05001009
1010#Enum SkYUVColorSpace ##
Cary Clark772953472018-02-12 09:38:08 -05001011#Subtopic YUV_ColorSpace ##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001012
1013# ------------------------------------------------------------------------------
Cary Clark2dc84ad2018-01-26 12:56:22 -05001014
1015#Struct SkImageInfo
1016
Cary Clark61313f32018-10-08 14:57:48 -04001017#Code
1018#Populate
1019##
1020
Cary Clark77b3f3a2018-11-07 14:59:03 -05001021Describes pixel dimensions and encoding. Bitmap, Image, Pixmap, and Surface
Cary Clark1a8d7622018-03-05 13:26:16 -05001022can be created from Image_Info. Image_Info can be retrieved from Bitmap and
1023Pixmap, but not from Image and Surface. For example, Image and Surface
1024implementations may defer pixel depth, so may not completely specify Image_Info.
1025
1026Image_Info contains dimensions, the pixel integral width and height. It encodes
1027how pixel bits describe Color_Alpha, transparency; Color components red, blue,
1028and green; and Color_Space, the range and linearity of colors.
Cary Clark2dc84ad2018-01-26 12:56:22 -05001029
Cary Clark2dc84ad2018-01-26 12:56:22 -05001030# ------------------------------------------------------------------------------
Cary Clark78de7512018-02-07 07:27:09 -05001031
Cary Clark2dc84ad2018-01-26 12:56:22 -05001032#Method SkImageInfo()
1033
Cary Clark61313f32018-10-08 14:57:48 -04001034#In Constructors
Cary Clark82f1f742018-06-28 08:50:35 -04001035#Line # creates with zeroed dimensions, kUnknown_SkColorType, kUnknown_SkAlphaType ##
Cary Clark09d80c02018-10-31 12:14:03 -04001036#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001037
1038#Example
Cary Clark1a8d7622018-03-05 13:26:16 -05001039#Height 32
1040#Description
1041An empty Image_Info may be passed to SkCanvas::accessTopLayerPixels as storage
1042for the Canvas actual Image_Info.
1043##
1044 SkImageInfo imageInfo;
1045 size_t rowBytes;
1046 SkIPoint origin;
Cary Clark681287e2018-03-16 11:34:15 -04001047 (void) canvas->accessTopLayerPixels(&imageInfo, &rowBytes, &origin);
Cary Clark1a8d7622018-03-05 13:26:16 -05001048 const char* alphaType[] = { "Unknown", "Opaque", "Premul", "Unpremul" };
1049 SkString string;
1050 string.printf("k%s_SkAlphaType", alphaType[(int) imageInfo.alphaType()]);
1051 SkPaint paint;
1052 canvas->drawString(string, 20, 20, paint);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001053##
1054
Cary Clark1a8d7622018-03-05 13:26:16 -05001055#SeeAlso Make MakeN32 MakeS32 MakeA8
Cary Clark2dc84ad2018-01-26 12:56:22 -05001056
1057#Method ##
1058
1059# ------------------------------------------------------------------------------
1060
1061#Method static SkImageInfo Make(int width, int height, SkColorType ct, SkAlphaType at,
1062 sk_sp<SkColorSpace> cs = nullptr)
Cary Clark61313f32018-10-08 14:57:48 -04001063#In Constructors
Cary Clarkab2621d2018-01-30 10:08:57 -05001064#Line # creates Image_Info from dimensions, Color_Type, Alpha_Type, Color_Space ##
Cary Clark09d80c02018-10-31 12:14:03 -04001065#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001066
1067#Example
Cary Clark1a8d7622018-03-05 13:26:16 -05001068#Height 48
1069 uint8_t storage[][5] = {{ 0xCA, 0xDA, 0xCA, 0xC9, 0xA3 },
1070 { 0xAC, 0xA8, 0x89, 0xA7, 0x87 },
1071 { 0x9B, 0xB5, 0xE5, 0x95, 0x46 },
1072 { 0x90, 0x81, 0xC5, 0x71, 0x33 },
1073 { 0x75, 0x55, 0x44, 0x40, 0x30 }};
1074 SkImageInfo imageInfo = SkImageInfo::Make(5, 5, kGray_8_SkColorType, kOpaque_SkAlphaType);
1075 SkPixmap pixmap(imageInfo, storage[0], sizeof(storage) / 5);
1076 SkBitmap bitmap;
1077 bitmap.installPixels(pixmap);
1078 canvas->scale(8, 8);
1079 canvas->drawBitmap(bitmap, 0, 0);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001080##
1081
Cary Clark1a8d7622018-03-05 13:26:16 -05001082#SeeAlso MakeN32 MakeN32Premul MakeS32 MakeA8
Cary Clark2dc84ad2018-01-26 12:56:22 -05001083
1084#Method ##
1085
1086# ------------------------------------------------------------------------------
1087
1088#Method static SkImageInfo MakeN32(int width, int height, SkAlphaType at,
1089 sk_sp<SkColorSpace> cs = nullptr)
Cary Clark61313f32018-10-08 14:57:48 -04001090#In Constructors
Cary Clarkab2621d2018-01-30 10:08:57 -05001091#Line # creates Image_Info with Native_Color_Type ##
Cary Clark09d80c02018-10-31 12:14:03 -04001092#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001093
1094#Example
Cary Clark1a8d7622018-03-05 13:26:16 -05001095#Height 128
1096 SkBitmap bitmap;
1097 bitmap.allocPixels(SkImageInfo::MakeN32(16, 16, kPremul_SkAlphaType));
1098 SkCanvas offscreen(bitmap);
1099 offscreen.clear(SK_ColorWHITE);
1100 SkPaint paint;
1101 offscreen.drawString("g", 0, 10, paint);
1102 canvas->scale(8, 8);
1103 canvas->drawBitmap(bitmap, 0, 0);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001104##
1105
Cary Clark1a8d7622018-03-05 13:26:16 -05001106#SeeAlso Make MakeN32Premul MakeS32 MakeA8
Cary Clark2dc84ad2018-01-26 12:56:22 -05001107
1108#Method ##
1109
1110# ------------------------------------------------------------------------------
1111
1112#Method static SkImageInfo MakeS32(int width, int height, SkAlphaType at)
1113
Cary Clark61313f32018-10-08 14:57:48 -04001114#In Constructors
Cary Clarkab2621d2018-01-30 10:08:57 -05001115#Line # creates Image_Info with Native_Color_Type, sRGB Color_Space ##
Cary Clark09d80c02018-10-31 12:14:03 -04001116#Populate
Cary Clark1a8d7622018-03-05 13:26:16 -05001117
1118#Example
1119#Set sRGB
1120#Height 128
1121#Description
Cary Clark682c58d2018-05-16 07:07:07 -04001122Top gradient is drawn to offScreen without Color_Space. It is darker than middle
1123gradient, drawn to offScreen with sRGB Color_Space. Bottom gradient shares bits
Cary Clark1a8d7622018-03-05 13:26:16 -05001124with middle, but does not specify the Color_Space in noColorSpaceBitmap. A source
1125without Color_Space is treated as sRGB; the bottom gradient is identical to the
1126middle gradient.
1127##
1128 const int width = 256;
1129 const int height = 32;
1130 SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
1131 SkColor gradColors[] = { 0xFFAA0055, 0xFF11CC88 };
1132 SkPoint gradPoints[] = { { 0, 0 }, { width, 0 } };
1133 SkPaint gradPaint;
1134 gradPaint.setShader(SkGradientShader::MakeLinear(gradPoints, gradColors, nullptr,
1135 SK_ARRAY_COUNT(gradColors), SkShader::kClamp_TileMode));
1136 SkBitmap bitmap;
1137 bitmap.allocPixels(SkImageInfo::MakeN32(width, height, kPremul_SkAlphaType));
Cary Clark682c58d2018-05-16 07:07:07 -04001138 SkCanvas offScreen(bitmap);
1139 offScreen.drawRect(SkRect::MakeWH(width, height), gradPaint);
Cary Clark1a8d7622018-03-05 13:26:16 -05001140 canvas->drawBitmap(bitmap, 0, 0);
1141 bitmap.allocPixels(SkImageInfo::MakeS32(width, height, kPremul_SkAlphaType));
1142 SkCanvas sRGBOffscreen(bitmap);
1143 sRGBOffscreen.drawRect(SkRect::MakeWH(width, height), gradPaint);
1144 canvas->drawBitmap(bitmap, 0, 48);
1145 SkBitmap noColorSpaceBitmap;
1146 noColorSpaceBitmap.setInfo(SkImageInfo::MakeN32(width, height, kPremul_SkAlphaType));
1147 noColorSpaceBitmap.setPixels(bitmap.getAddr(0, 0));
1148 canvas->drawBitmap(noColorSpaceBitmap, 0, 96);
1149##
1150
1151#SeeAlso Make MakeN32 MakeN32Premul MakeA8
Cary Clark2dc84ad2018-01-26 12:56:22 -05001152
1153#Method ##
1154
1155# ------------------------------------------------------------------------------
1156
1157#Method static SkImageInfo MakeN32Premul(int width, int height, sk_sp<SkColorSpace> cs = nullptr)
1158
Cary Clark61313f32018-10-08 14:57:48 -04001159#In Constructors
Cary Clarkab2621d2018-01-30 10:08:57 -05001160#Line # creates Image_Info with Native_Color_Type, kPremul_SkAlphaType ##
Cary Clark09d80c02018-10-31 12:14:03 -04001161#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001162
1163#Example
Cary Clark06c20f32018-03-20 15:53:27 -04001164#Height 128
Cary Clark1a8d7622018-03-05 13:26:16 -05001165 SkBitmap bitmap;
1166 bitmap.allocPixels(SkImageInfo::MakeN32Premul(18, 18));
1167 SkCanvas offscreen(bitmap);
1168 offscreen.clear(SK_ColorWHITE);
1169 SkPaint paint;
Mike Reed729bb192019-02-13 16:56:13 -05001170 SkFont font(nullptr, 15);
1171 offscreen.drawString("\xF0\x9F\x98\xB8", 1, 15, font, paint);
Cary Clark1a8d7622018-03-05 13:26:16 -05001172 canvas->scale(6, 6);
1173 canvas->drawBitmap(bitmap, 0, 0);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001174##
1175
Cary Clark1a8d7622018-03-05 13:26:16 -05001176#SeeAlso MakeN32 MakeS32 MakeA8 Make
Cary Clark2dc84ad2018-01-26 12:56:22 -05001177
1178#Method ##
1179
1180# ------------------------------------------------------------------------------
1181
1182#Method static SkImageInfo MakeN32Premul(const SkISize& size)
1183
Cary Clark61313f32018-10-08 14:57:48 -04001184#In Constructors
Cary Clark09d80c02018-10-31 12:14:03 -04001185#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001186
1187#Example
Cary Clark06c20f32018-03-20 15:53:27 -04001188#Height 128
Cary Clark1a8d7622018-03-05 13:26:16 -05001189 SkBitmap bitmap;
1190 bitmap.allocPixels(SkImageInfo::MakeN32Premul({18, 18}));
1191 SkCanvas offscreen(bitmap);
1192 offscreen.clear(SK_ColorWHITE);
1193 SkPaint paint;
Mike Reed729bb192019-02-13 16:56:13 -05001194 SkFont font(nullptr, 15);
1195 offscreen.drawString("\xF0\x9F\x98\xB9", 1, 15, font, paint);
Cary Clark1a8d7622018-03-05 13:26:16 -05001196 canvas->scale(6, 6);
1197 canvas->drawBitmap(bitmap, 0, 0);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001198##
1199
Cary Clark682c58d2018-05-16 07:07:07 -04001200#SeeAlso MakeN32 MakeS32 MakeA8 Make
Cary Clark2dc84ad2018-01-26 12:56:22 -05001201
1202#Method ##
1203
1204# ------------------------------------------------------------------------------
1205
1206#Method static SkImageInfo MakeA8(int width, int height)
1207
Cary Clark61313f32018-10-08 14:57:48 -04001208#In Constructors
Cary Clarkab2621d2018-01-30 10:08:57 -05001209#Line # creates Image_Info with kAlpha_8_SkColorType, kPremul_SkAlphaType ##
Cary Clark09d80c02018-10-31 12:14:03 -04001210#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001211
1212#Example
Cary Clark681287e2018-03-16 11:34:15 -04001213#Height 64
1214 uint8_t pixels[][8] = { { 0x00, 0x00, 0x3f, 0x00, 0x00, 0x00, 0x00, 0x00},
1215 { 0x00, 0x7f, 0xff, 0x3f, 0x3f, 0x7f, 0x3f, 0x00},
1216 { 0x3f, 0xff, 0x7f, 0x00, 0x7f, 0xff, 0x7f, 0x00},
1217 { 0x00, 0x3f, 0x00, 0x00, 0x3f, 0x7f, 0x3f, 0x00},
1218 { 0x3f, 0x7f, 0x7f, 0x3f, 0x00, 0x00, 0x00, 0x00},
1219 { 0x7f, 0xff, 0xff, 0x7f, 0x00, 0x3f, 0x7f, 0x3f},
1220 { 0x7f, 0xff, 0xff, 0x7f, 0x00, 0x7f, 0xff, 0x7f},
1221 { 0x3f, 0x7f, 0x7f, 0x3f, 0x00, 0x3f, 0x7f, 0x3f} };
1222 SkBitmap bitmap;
1223 bitmap.installPixels(SkImageInfo::MakeA8(8, 8),
1224 (void*) pixels, sizeof(pixels[0]));
1225 SkPaint paint;
1226 canvas->scale(4, 4);
1227 for (auto color : { SK_ColorRED, SK_ColorBLUE, 0xFF007F00} ) {
1228 paint.setColor(color);
1229 canvas->drawBitmap(bitmap, 0, 0, &paint);
1230 canvas->translate(12, 0);
1231 }
Cary Clark2dc84ad2018-01-26 12:56:22 -05001232##
1233
Cary Clark1a8d7622018-03-05 13:26:16 -05001234#SeeAlso MakeN32 MakeS32 Make
Cary Clark2dc84ad2018-01-26 12:56:22 -05001235
1236#Method ##
1237
1238# ------------------------------------------------------------------------------
1239
1240#Method static SkImageInfo MakeUnknown(int width, int height)
1241
Cary Clark61313f32018-10-08 14:57:48 -04001242#In Constructors
Cary Clarkab2621d2018-01-30 10:08:57 -05001243#Line # creates Image_Info with kUnknown_SkColorType, kUnknown_SkAlphaType ##
Cary Clark09d80c02018-10-31 12:14:03 -04001244#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001245
1246#Example
Cary Clark1a8d7622018-03-05 13:26:16 -05001247#Height 32
1248#Width 384
1249SkImageInfo info; // default constructor
1250SkString string;
1251string.printf("SkImageInfo() %c= SkImageInfo::MakeUnknown(0, 0)",
1252 info == SkImageInfo::MakeUnknown(0, 0) ? '=' : '!');
1253SkPaint paint;
1254canvas->drawString(string, 0, 12, paint);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001255##
1256
Cary Clark1a8d7622018-03-05 13:26:16 -05001257#SeeAlso SkImageInfo() MakeN32 MakeS32 Make
Cary Clark2dc84ad2018-01-26 12:56:22 -05001258
1259#Method ##
1260
1261# ------------------------------------------------------------------------------
1262
1263#Method static SkImageInfo MakeUnknown()
1264
Cary Clark61313f32018-10-08 14:57:48 -04001265#In Constructors
Cary Clark09d80c02018-10-31 12:14:03 -04001266#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001267
1268#Example
Cary Clark1a8d7622018-03-05 13:26:16 -05001269#Height 32
1270#Width 384
1271SkImageInfo info; // default constructor
1272SkString string;
1273string.printf("SkImageInfo() %c= SkImageInfo::MakeUnknown()",
1274 info == SkImageInfo::MakeUnknown() ? '=' : '!');
1275SkPaint paint;
1276canvas->drawString(string, 0, 12, paint);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001277##
1278
Cary Clark1a8d7622018-03-05 13:26:16 -05001279#SeeAlso SkImageInfo() MakeN32 MakeS32 Make
Cary Clark2dc84ad2018-01-26 12:56:22 -05001280
1281#Method ##
1282
Cary Clark2dc84ad2018-01-26 12:56:22 -05001283
1284# ------------------------------------------------------------------------------
Cary Clark78de7512018-02-07 07:27:09 -05001285#Subtopic Property
Cary Clark78de7512018-02-07 07:27:09 -05001286#Line # metrics and attributes ##
1287##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001288
1289#Method int width() const
Cary Clark78de7512018-02-07 07:27:09 -05001290#In Property
Cary Clark1a8d7622018-03-05 13:26:16 -05001291#Line # returns pixel column count ##
Cary Clark09d80c02018-10-31 12:14:03 -04001292#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001293
1294#Example
Cary Clark1a8d7622018-03-05 13:26:16 -05001295#Image 4
1296#Height 96
1297 canvas->translate(10, 10);
1298 canvas->drawBitmap(source, 0, 0);
1299 SkImageInfo imageInfo = source.info();
1300 canvas->translate(0, imageInfo.height());
1301 SkPaint paint;
Cary Clark1a8d7622018-03-05 13:26:16 -05001302 canvas->drawLine(0, 10, imageInfo.width(), 10, paint);
Cary Clark14768f62018-10-29 20:33:51 -04001303 canvas->drawString("width", imageInfo.width() / 2 - 15, 25, paint);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001304##
1305
Cary Clark1a8d7622018-03-05 13:26:16 -05001306#SeeAlso height SkBitmap::width SkPixelRef::width SkImage::width SkSurface::width
Cary Clark2dc84ad2018-01-26 12:56:22 -05001307
1308#Method ##
1309
1310# ------------------------------------------------------------------------------
1311
1312#Method int height() const
Cary Clark78de7512018-02-07 07:27:09 -05001313#In Property
Cary Clark1a8d7622018-03-05 13:26:16 -05001314#Line # returns pixel row count ##
Cary Clark09d80c02018-10-31 12:14:03 -04001315#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001316
1317#Example
Cary Clark1a8d7622018-03-05 13:26:16 -05001318#Image 4
1319#Height 96
1320 canvas->translate(10, 20);
1321 canvas->drawBitmap(source, 0, 0);
1322 SkImageInfo imageInfo = source.info();
1323 SkPaint paint;
Cary Clark1a8d7622018-03-05 13:26:16 -05001324 canvas->drawLine(imageInfo.width() + 10, 0, imageInfo.width() + 10, imageInfo.height(), paint);
Cary Clark14768f62018-10-29 20:33:51 -04001325 canvas->drawString("height", imageInfo.width() + 15, imageInfo.height() / 2, paint);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001326##
1327
Cary Clark1a8d7622018-03-05 13:26:16 -05001328#SeeAlso width SkBitmap::height SkPixelRef::height SkImage::height SkSurface::height
Cary Clark2dc84ad2018-01-26 12:56:22 -05001329
1330#Method ##
1331
1332# ------------------------------------------------------------------------------
1333
1334#Method SkColorType colorType() const
Cary Clark78de7512018-02-07 07:27:09 -05001335#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001336#Line # returns Color_Type ##
Cary Clark1a8d7622018-03-05 13:26:16 -05001337Returns Color_Type, one of: #list_of_color_types#.
1338
1339#Return Color_Type ##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001340
1341#Example
Cary Clark681287e2018-03-16 11:34:15 -04001342 const char* colors[] = {"Unknown", "Alpha_8", "RGB_565", "ARGB_4444", "RGBA_8888", "RGB_888x",
1343 "BGRA_8888", "RGBA_1010102", "RGB_101010x", "Gray_8", "RGBA_F16"};
1344 SkImageInfo info = SkImageInfo::MakeA8(16, 32);
1345 SkDebugf("color type: k" "%s" "_SkColorType\n", colors[info.colorType()]);
1346#StdOut
1347color type: kAlpha_8_SkColorType
1348##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001349##
1350
Cary Clark681287e2018-03-16 11:34:15 -04001351#SeeAlso alphaType SkPixmap::colorType SkBitmap::colorType
Cary Clark2dc84ad2018-01-26 12:56:22 -05001352
1353#Method ##
1354
1355# ------------------------------------------------------------------------------
1356
1357#Method SkAlphaType alphaType() const
Cary Clark78de7512018-02-07 07:27:09 -05001358#In Property
Cary Clark682c58d2018-05-16 07:07:07 -04001359#Line # returns Alpha_Type ##
Cary Clark681287e2018-03-16 11:34:15 -04001360Returns Alpha_Type, one of: #list_of_alpha_types#.
1361
1362#Return Alpha_Type ##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001363
1364#Example
Cary Clark681287e2018-03-16 11:34:15 -04001365 const char* alphas[] = {"Unknown", "Opaque", "Premul", "Unpremul"};
1366 SkImageInfo info = SkImageInfo::MakeA8(16, 32);
1367 SkDebugf("alpha type: k" "%s" "_SkAlphaType\n", alphas[info.alphaType()]);
1368#StdOut
1369alpha type: kPremul_SkAlphaType
1370##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001371##
1372
Cary Clark681287e2018-03-16 11:34:15 -04001373#SeeAlso colorType SkPixmap::alphaType SkBitmap::alphaType
Cary Clark2dc84ad2018-01-26 12:56:22 -05001374
1375#Method ##
1376
1377# ------------------------------------------------------------------------------
1378
1379#Method SkColorSpace* colorSpace() const
Cary Clark78de7512018-02-07 07:27:09 -05001380#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001381#Line # returns Color_Space ##
Cary Clark09d80c02018-10-31 12:14:03 -04001382#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001383
1384#Example
Cary Clark681287e2018-03-16 11:34:15 -04001385#Description
1386SkColorSpace::MakeSRGBLinear creates Color_Space with linear gamma
1387and an sRGB gamut. This Color_Space gamma is not close to sRGB gamma.
1388##
Cary Clark682c58d2018-05-16 07:07:07 -04001389 SkImageInfo info = SkImageInfo::MakeN32(16, 32, kPremul_SkAlphaType,
Cary Clark681287e2018-03-16 11:34:15 -04001390 SkColorSpace::MakeSRGBLinear());
1391 SkColorSpace* colorSpace = info.colorSpace();
1392 SkDebugf("gammaCloseToSRGB: %s gammaIsLinear: %s isSRGB: %s\n",
1393 colorSpace->gammaCloseToSRGB() ? "true" : "false",
1394 colorSpace->gammaIsLinear() ? "true" : "false",
1395 colorSpace->isSRGB() ? "true" : "false");
1396#StdOut
1397gammaCloseToSRGB: false gammaIsLinear: true isSRGB: false
1398##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001399##
1400
Cary Clark681287e2018-03-16 11:34:15 -04001401#SeeAlso Color_Space SkPixmap::colorSpace SkBitmap::colorSpace
Cary Clark2dc84ad2018-01-26 12:56:22 -05001402
1403#Method ##
1404
1405# ------------------------------------------------------------------------------
1406
1407#Method sk_sp<SkColorSpace> refColorSpace() const
Cary Clark78de7512018-02-07 07:27:09 -05001408#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001409#Line # returns Color_Space ##
Cary Clark09d80c02018-10-31 12:14:03 -04001410#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001411
1412#Example
Cary Clark682c58d2018-05-16 07:07:07 -04001413 SkImageInfo info1 = SkImageInfo::MakeN32(16, 32, kPremul_SkAlphaType,
Cary Clark681287e2018-03-16 11:34:15 -04001414 SkColorSpace::MakeSRGBLinear());
1415 SkImageInfo info2 = SkImageInfo::MakeN32(16, 32, kPremul_SkAlphaType,
1416 info1.refColorSpace());
1417 SkColorSpace* colorSpace = info2.colorSpace();
1418 SkDebugf("gammaCloseToSRGB: %s gammaIsLinear: %s isSRGB: %s\n",
1419 colorSpace->gammaCloseToSRGB() ? "true" : "false",
1420 colorSpace->gammaIsLinear() ? "true" : "false",
1421 colorSpace->isSRGB() ? "true" : "false");
Cary Clark2dc84ad2018-01-26 12:56:22 -05001422##
1423
Cary Clark681287e2018-03-16 11:34:15 -04001424#SeeAlso Color_Space SkBitmap::refColorSpace
Cary Clark2dc84ad2018-01-26 12:56:22 -05001425
1426#Method ##
1427
1428# ------------------------------------------------------------------------------
1429
1430#Method bool isEmpty() const
Cary Clark78de7512018-02-07 07:27:09 -05001431#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001432#Line # returns if dimensions contain pixels ##
Cary Clark09d80c02018-10-31 12:14:03 -04001433#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001434
1435#Example
Cary Clark681287e2018-03-16 11:34:15 -04001436 for (int width : { 0, 2 } ) {
1437 for (int height : { 0, 2 } ) {
1438 SkImageInfo imageInfo= SkImageInfo::MakeA8(width, height);
1439 SkDebugf("width: %d height: %d empty: %s\n", width, height,
1440 imageInfo.isEmpty() ? "true" : "false");
1441 }
1442 }
1443#StdOut
1444width: 0 height: 0 empty: true
1445width: 0 height: 2 empty: true
1446width: 2 height: 0 empty: true
1447width: 2 height: 2 empty: false
1448##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001449##
1450
Cary Clark681287e2018-03-16 11:34:15 -04001451#SeeAlso dimensions bounds SkBitmap::empty SkPixmap::bounds
Cary Clark2dc84ad2018-01-26 12:56:22 -05001452
1453#Method ##
1454
1455# ------------------------------------------------------------------------------
1456
1457#Method bool isOpaque() const
Cary Clark78de7512018-02-07 07:27:09 -05001458#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001459#Line # returns if Alpha_Type is kOpaque_SkAlphaType ##
Cary Clark09d80c02018-10-31 12:14:03 -04001460#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001461
1462#Example
Cary Clark681287e2018-03-16 11:34:15 -04001463 const int height = 2;
1464 const int width = 2;
1465 SkBitmap bitmap;
1466 SkImageInfo imageInfo = SkImageInfo::Make(width, height, kN32_SkColorType, kPremul_SkAlphaType);
1467 bitmap.setInfo(imageInfo);
1468 for (int index = 0; index < 2; ++index) {
1469 bitmap.allocPixels();
1470 bitmap.eraseColor(0x00000000);
1471 SkDebugf("isOpaque: %s\n", imageInfo.isOpaque() ? "true" : "false");
1472 bitmap.eraseColor(0xFFFFFFFF);
1473 SkDebugf("isOpaque: %s\n", imageInfo.isOpaque() ? "true" : "false");
1474 imageInfo = imageInfo.makeAlphaType(kOpaque_SkAlphaType);
1475 bitmap.setInfo(imageInfo);
1476 }
1477#StdOut
1478isOpaque: false
1479isOpaque: false
1480isOpaque: true
1481isOpaque: true
1482##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001483##
1484
Cary Clark681287e2018-03-16 11:34:15 -04001485#SeeAlso Color_Alpha SkColorTypeValidateAlphaType SkBitmap::isOpaque SkImage::isOpaque SkPixmap::isOpaque
Cary Clark2dc84ad2018-01-26 12:56:22 -05001486
1487#Method ##
1488
1489# ------------------------------------------------------------------------------
1490
1491#Method SkISize dimensions() const
Cary Clark78de7512018-02-07 07:27:09 -05001492#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001493#Line # returns width() and height() ##
Cary Clark09d80c02018-10-31 12:14:03 -04001494#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001495
1496#Example
Cary Clark681287e2018-03-16 11:34:15 -04001497 const int height = 2;
1498 const int width = 2;
1499 SkImageInfo imageInfo = SkImageInfo::Make(width, height, kN32_SkColorType, kPremul_SkAlphaType);
1500 SkISize dimensions = imageInfo.dimensions();
1501 SkIRect bounds = imageInfo.bounds();
1502 SkIRect dimensionsAsBounds = SkIRect::MakeSize(dimensions);
1503 SkDebugf("dimensionsAsBounds %c= bounds\n", dimensionsAsBounds == bounds ? '=' : '!');
1504#StdOut
1505dimensionsAsBounds == bounds
1506##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001507##
1508
Cary Clark681287e2018-03-16 11:34:15 -04001509#SeeAlso width height bounds SkBitmap::dimensions
Cary Clark2dc84ad2018-01-26 12:56:22 -05001510
1511#Method ##
1512
1513# ------------------------------------------------------------------------------
1514
1515#Method SkIRect bounds() const
Cary Clark78de7512018-02-07 07:27:09 -05001516#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001517#Line # returns width() and height() as Rectangle ##
Cary Clark09d80c02018-10-31 12:14:03 -04001518#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001519
1520#Example
Cary Clark681287e2018-03-16 11:34:15 -04001521#Height 64
1522#Image 4
1523 canvas->scale(.5f, .5f);
1524 SkImageInfo imageInfo = source.info();
1525 SkIRect bounds = imageInfo.bounds();
1526 for (int x : { 0, bounds.width() } ) {
1527 for (int y : { 0, bounds.height() } ) {
1528 canvas->drawBitmap(source, x, y);
1529 }
1530 }
Cary Clark2dc84ad2018-01-26 12:56:22 -05001531##
1532
Cary Clark681287e2018-03-16 11:34:15 -04001533#SeeAlso width height dimensions
Cary Clark2dc84ad2018-01-26 12:56:22 -05001534
1535#Method ##
1536
1537# ------------------------------------------------------------------------------
1538
1539#Method bool gammaCloseToSRGB() const
Cary Clark78de7512018-02-07 07:27:09 -05001540#In Property
Cary Clark682c58d2018-05-16 07:07:07 -04001541#Line # returns if Color_Space gamma is approximately the same as sRGB ##
Cary Clark681287e2018-03-16 11:34:15 -04001542
1543Returns true if associated Color_Space is not nullptr, and Color_Space gamma
Cary Clark682c58d2018-05-16 07:07:07 -04001544is approximately the same as sRGB.
1545This includes the
Cary Clark681287e2018-03-16 11:34:15 -04001546###$
1547$A sRGB transfer function $ https://en.wikipedia.org/wiki/SRGB#The_sRGB_transfer_function_(%22gamma%22) $$
1548$$$#
1549as well as a gamma curve described by a 2.2 exponent.
1550
1551#Return true if Color_Space gamma is approximately the same as sRGB ##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001552
1553#Example
Cary Clark681287e2018-03-16 11:34:15 -04001554#Height 144
1555 const int width = 256;
1556 const int height = 64;
1557 auto drawLabel = [=](const char* what, bool closeToSRGB) -> void {
1558 SkString string;
1559 string.printf("%s gamma is %s" "close to sRGB", what, closeToSRGB ? "" : "not ");
1560 SkPaint paint;
1561 paint.setAntiAlias(true);
Cary Clark14768f62018-10-29 20:33:51 -04001562 canvas->drawString(string, 20, 56, paint);
Cary Clark681287e2018-03-16 11:34:15 -04001563 };
1564 SkColor gradColors[] = { 0xFFFF7F00, 0xFF00FF7F, 0xFF0000FF, 0xFF7F7FFF };
1565 SkPoint gradPoints[] = { { 0, 0 }, { width, 0 }, { width * 2, 0 }, { width * 3, 0 } };
1566 SkPaint gradPaint;
1567 gradPaint.setShader(SkGradientShader::MakeLinear(gradPoints, gradColors, nullptr,
1568 SK_ARRAY_COUNT(gradColors), SkShader::kClamp_TileMode));
1569 canvas->drawRect(SkRect::MakeWH(width, height), gradPaint);
1570 drawLabel("canvas", canvas->imageInfo().gammaCloseToSRGB());
1571 SkBitmap bitmap;
1572 SkImageInfo offscreenInfo = SkImageInfo::MakeS32(width, height, kPremul_SkAlphaType);
1573 bitmap.allocPixels(offscreenInfo);
1574 SkCanvas sRGBOffscreen(bitmap);
1575 sRGBOffscreen.drawRect(SkRect::MakeWH(width, height), gradPaint);
1576 canvas->translate(0, 80);
1577 canvas->drawBitmap(bitmap, 0, 0);
1578 drawLabel("offscreen", offscreenInfo.gammaCloseToSRGB());
Cary Clark2dc84ad2018-01-26 12:56:22 -05001579##
1580
Cary Clark681287e2018-03-16 11:34:15 -04001581#SeeAlso SkColorSpace::gammaCloseToSRGB
Cary Clark2dc84ad2018-01-26 12:56:22 -05001582
1583#Method ##
1584
1585# ------------------------------------------------------------------------------
1586
1587#Method SkImageInfo makeWH(int newWidth, int newHeight) const
Cary Clark61313f32018-10-08 14:57:48 -04001588#In Constructors
Cary Clarkab2621d2018-01-30 10:08:57 -05001589#Line # creates Image_Info with changed dimensions ##
Cary Clark09d80c02018-10-31 12:14:03 -04001590#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001591
1592#Example
Cary Clark681287e2018-03-16 11:34:15 -04001593#Height 144
1594#Image 3
1595 SkImageInfo canvasImageInfo = canvas->imageInfo();
1596 SkRect canvasBounds = SkRect::Make(canvasImageInfo.bounds());
1597 canvas->drawBitmapRect(source, source.bounds(), canvasBounds, nullptr);
Cary Clark682c58d2018-05-16 07:07:07 -04001598 SkImageInfo insetImageInfo =
Cary Clark681287e2018-03-16 11:34:15 -04001599 canvasImageInfo.makeWH(canvasBounds.width() / 2, canvasBounds.height() / 2);
1600 SkBitmap inset;
1601 inset.allocPixels(insetImageInfo);
1602 SkCanvas offscreen(inset);
1603 offscreen.drawBitmapRect(source, source.bounds(), SkRect::Make(inset.bounds()), nullptr);
1604 canvas->drawBitmap(inset, canvasBounds.width() / 4, canvasBounds.height() / 4);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001605##
1606
Cary Clark682c58d2018-05-16 07:07:07 -04001607#SeeAlso Make makeAlphaType makeColorSpace makeColorType
Cary Clark2dc84ad2018-01-26 12:56:22 -05001608
1609#Method ##
1610
1611# ------------------------------------------------------------------------------
1612
1613#Method SkImageInfo makeAlphaType(SkAlphaType newAlphaType) const
Cary Clark61313f32018-10-08 14:57:48 -04001614#In Constructors
Cary Clarkab2621d2018-01-30 10:08:57 -05001615#Line # creates Image_Info with changed Alpha_Type ##
Cary Clark09d80c02018-10-31 12:14:03 -04001616#Populate
Cary Clark681287e2018-03-16 11:34:15 -04001617
1618#Example
1619#Image 3
1620 const int width = 256;
1621 const int height = 128;
1622 SkColor pixels[height][width];
1623 for (int y = 0; y < height; ++y) {
1624 for (int x = 0; x < width; ++x) {
Cary Clark682c58d2018-05-16 07:07:07 -04001625 int red = SkScalarRoundToInt(255 * SkScalarAbs(SkScalarSin((x * 4 + y) * 0.03f)));
1626 int blue = SkScalarRoundToInt(255 * SkScalarAbs(SkScalarCos((x * 3 + y) * 0.04f)));
Cary Clark681287e2018-03-16 11:34:15 -04001627 int green = SkScalarRoundToInt(255 * SkScalarAbs(SkScalarSin((x * 2 + y) * 0.05f)));
1628 int alpha = SkScalarRoundToInt(255 * SkScalarAbs(SkScalarCos((x * 1 + y) * 0.006f)));
Cary Clark682c58d2018-05-16 07:07:07 -04001629 pixels[y][x] =
Cary Clark681287e2018-03-16 11:34:15 -04001630 SkColorSetARGB(alpha, red * alpha / 255, green * alpha / 255, blue * alpha / 255);
1631 }
1632 }
1633 SkBitmap bitmap;
1634 SkImageInfo info = SkImageInfo::Make(width, height, kBGRA_8888_SkColorType, kPremul_SkAlphaType);
1635 bitmap.installPixels(info, (void*) pixels, sizeof(SkColor) * width);
1636 canvas->drawBitmap(source, 0, 0);
1637 canvas->drawBitmap(bitmap, 0, 0);
1638 SkImageInfo unpremulInfo = info.makeAlphaType(kUnpremul_SkAlphaType);
1639 bitmap.installPixels(unpremulInfo, (void*) pixels, sizeof(SkColor) * width);
1640 canvas->drawBitmap(bitmap, 0, 128);
1641##
1642
1643#SeeAlso Make MakeA8 makeColorType makeColorSpace
Cary Clark2dc84ad2018-01-26 12:56:22 -05001644
1645#Method ##
1646
1647# ------------------------------------------------------------------------------
1648
1649#Method SkImageInfo makeColorType(SkColorType newColorType) const
Cary Clark61313f32018-10-08 14:57:48 -04001650#In Constructors
Cary Clarkab2621d2018-01-30 10:08:57 -05001651#Line # creates Image_Info with changed Color_Type ##
Cary Clark09d80c02018-10-31 12:14:03 -04001652#Populate
Cary Clark681287e2018-03-16 11:34:15 -04001653
1654#Example
1655 const int width = 256;
1656 const int height = 128;
1657 SkColor pixels[height][width];
1658 for (int y = 0; y < height; ++y) {
1659 for (int x = 0; x < width; ++x) {
Cary Clark682c58d2018-05-16 07:07:07 -04001660 int red = SkScalarRoundToInt(255 * SkScalarAbs(SkScalarSin((x * 4 + y) * 0.03f)));
1661 int blue = SkScalarRoundToInt(255 * SkScalarAbs(SkScalarCos((x * 3 + y) * 0.04f)));
Cary Clark681287e2018-03-16 11:34:15 -04001662 int green = SkScalarRoundToInt(255 * SkScalarAbs(SkScalarSin((x * 2 + y) * 0.05f)));
1663 int alpha = SkScalarRoundToInt(255 * SkScalarAbs(SkScalarCos((x * 1 + y) * 0.006f)));
Cary Clark682c58d2018-05-16 07:07:07 -04001664 pixels[y][x] =
Cary Clark681287e2018-03-16 11:34:15 -04001665 SkColorSetARGB(alpha, red * alpha / 255, green * alpha / 255, blue * alpha / 255);
1666 }
1667 }
1668 SkBitmap bitmap;
1669 SkImageInfo info = SkImageInfo::Make(width, height, kBGRA_8888_SkColorType, kPremul_SkAlphaType);
1670 bitmap.installPixels(info, (void*) pixels, sizeof(SkColor) * width);
1671 canvas->drawBitmap(source, 0, 0);
1672 canvas->drawBitmap(bitmap, 0, 0);
1673 SkImageInfo rgbaInfo = info.makeColorType(kRGBA_8888_SkColorType);
1674 bitmap.installPixels(rgbaInfo, (void*) pixels, sizeof(SkColor) * width);
1675 canvas->drawBitmap(bitmap, 0, 128);
1676##
1677
1678#SeeAlso Make makeAlphaType makeColorSpace
Cary Clark2dc84ad2018-01-26 12:56:22 -05001679
1680#Method ##
1681
1682# ------------------------------------------------------------------------------
1683
1684#Method SkImageInfo makeColorSpace(sk_sp<SkColorSpace> cs) const
Cary Clark61313f32018-10-08 14:57:48 -04001685#In Constructors
Cary Clarkab2621d2018-01-30 10:08:57 -05001686#Line # creates Image_Info with changed Color_Space ##
Cary Clark09d80c02018-10-31 12:14:03 -04001687#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001688
1689#Example
Cary Clark681287e2018-03-16 11:34:15 -04001690#Height 224
1691 const int width = 256;
1692 const int height = 64;
1693 auto drawLabel = [=](const char* what, bool closeToSRGB) -> void {
1694 SkString string;
1695 string.printf("%s gamma is %s" "close to sRGB", what, closeToSRGB ? "" : "not ");
1696 SkPaint paint;
1697 paint.setAntiAlias(true);
Cary Clark14768f62018-10-29 20:33:51 -04001698 canvas->drawString(string, 20, 56, paint);
Cary Clark681287e2018-03-16 11:34:15 -04001699 };
1700 SkColor gradColors[] = { 0xFFFF7F00, 0xFF00FF7F, 0xFF0000FF, 0xFF7F7FFF };
1701 SkPoint gradPoints[] = { { 0, 0 }, { width, 0 }, { width * 2, 0 }, { width * 3, 0 } };
1702 SkPaint gradPaint;
1703 gradPaint.setShader(SkGradientShader::MakeLinear(gradPoints, gradColors, nullptr,
1704 SK_ARRAY_COUNT(gradColors), SkShader::kClamp_TileMode));
1705 canvas->drawRect(SkRect::MakeWH(width, height), gradPaint);
1706 drawLabel("canvas", canvas->imageInfo().gammaCloseToSRGB());
1707 SkBitmap bitmap;
1708 SkImageInfo offscreenInfo = SkImageInfo::MakeS32(width, height, kPremul_SkAlphaType);
1709 bitmap.allocPixels(offscreenInfo);
1710 SkCanvas sRGBOffscreen(bitmap);
1711 sRGBOffscreen.drawRect(SkRect::MakeWH(width, height), gradPaint);
1712 canvas->translate(0, 80);
1713 canvas->drawBitmap(bitmap, 0, 0);
1714 drawLabel("offscreen", offscreenInfo.gammaCloseToSRGB());
1715 SkImageInfo linearGamma =
1716 offscreenInfo.makeColorSpace(offscreenInfo.colorSpace()->makeLinearGamma());
1717 bitmap.allocPixels(linearGamma);
1718 SkCanvas lgOffscreen(bitmap);
1719 lgOffscreen.drawRect(SkRect::MakeWH(width, height), gradPaint);
1720 canvas->translate(0, 80);
1721 canvas->drawBitmap(bitmap, 0, 0);
1722 drawLabel("linear", linearGamma.gammaCloseToSRGB());
Cary Clark2dc84ad2018-01-26 12:56:22 -05001723##
1724
Cary Clark681287e2018-03-16 11:34:15 -04001725#SeeAlso Make MakeS32 makeAlphaType makeColorType
Cary Clark2dc84ad2018-01-26 12:56:22 -05001726
1727#Method ##
1728
1729# ------------------------------------------------------------------------------
1730
1731#Method int bytesPerPixel() const
Cary Clark78de7512018-02-07 07:27:09 -05001732#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001733#Line # returns number of bytes in pixel based on Color_Type ##
Cary Clark09d80c02018-10-31 12:14:03 -04001734#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001735
1736#Example
Cary Clark681287e2018-03-16 11:34:15 -04001737 const char* colors[] = {"Unknown", "Alpha_8", "RGB_565", "ARGB_4444", "RGBA_8888", "RGB_888x",
1738 "BGRA_8888", "RGBA_1010102", "RGB_101010x", "Gray_8", "RGBA_F16"};
1739 for (SkColorType colorType : { #list_of_color_types#
1740 } ) {
1741 SkImageInfo info = SkImageInfo::Make(1, 1, colorType, kOpaque_SkAlphaType);
1742 SkDebugf("color: k" "%s" "_SkColorType" "%*s" "bytesPerPixel: %d\n",
1743 colors[colorType], 13 - strlen(colors[colorType]), " ",
1744 info.bytesPerPixel());
1745 }
1746#StdOut
1747color: kUnknown_SkColorType bytesPerPixel: 0
1748color: kAlpha_8_SkColorType bytesPerPixel: 1
1749color: kRGB_565_SkColorType bytesPerPixel: 2
1750color: kARGB_4444_SkColorType bytesPerPixel: 2
1751color: kRGBA_8888_SkColorType bytesPerPixel: 4
1752color: kRGB_888x_SkColorType bytesPerPixel: 4
1753color: kBGRA_8888_SkColorType bytesPerPixel: 4
1754color: kRGBA_1010102_SkColorType bytesPerPixel: 4
1755color: kRGB_101010x_SkColorType bytesPerPixel: 4
1756color: kGray_8_SkColorType bytesPerPixel: 1
1757color: kRGBA_F16_SkColorType bytesPerPixel: 8
1758##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001759##
1760
Cary Clark681287e2018-03-16 11:34:15 -04001761#SeeAlso width shiftPerPixel SkBitmap::bytesPerPixel
Cary Clark2dc84ad2018-01-26 12:56:22 -05001762
1763#Method ##
1764
1765# ------------------------------------------------------------------------------
1766
1767#Method int shiftPerPixel() const
Cary Clark78de7512018-02-07 07:27:09 -05001768#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001769#Line # returns bit shift from pixels to bytes ##
Cary Clark09d80c02018-10-31 12:14:03 -04001770#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001771
1772#Example
Cary Clark681287e2018-03-16 11:34:15 -04001773 const char* colors[] = {"Unknown", "Alpha_8", "RGB_565", "ARGB_4444", "RGBA_8888", "RGB_888x",
1774 "BGRA_8888", "RGBA_1010102", "RGB_101010x", "Gray_8", "RGBA_F16"};
1775 for (SkColorType colorType : { #list_of_color_types#
1776 } ) {
1777 SkImageInfo info = SkImageInfo::Make(1, 1, colorType, kOpaque_SkAlphaType);
1778 SkDebugf("color: k" "%s" "_SkColorType" "%*s" "shiftPerPixel: %d\n",
1779 colors[colorType], 14 - strlen(colors[colorType]), " ",
1780 info.shiftPerPixel());
1781 }
1782#StdOut
1783color: kUnknown_SkColorType shiftPerPixel: 0
1784color: kAlpha_8_SkColorType shiftPerPixel: 0
1785color: kRGB_565_SkColorType shiftPerPixel: 1
1786color: kARGB_4444_SkColorType shiftPerPixel: 1
1787color: kRGBA_8888_SkColorType shiftPerPixel: 2
1788color: kRGB_888x_SkColorType shiftPerPixel: 2
1789color: kBGRA_8888_SkColorType shiftPerPixel: 2
1790color: kRGBA_1010102_SkColorType shiftPerPixel: 2
1791color: kRGB_101010x_SkColorType shiftPerPixel: 2
1792color: kGray_8_SkColorType shiftPerPixel: 0
1793color: kRGBA_F16_SkColorType shiftPerPixel: 3
1794##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001795##
1796
Cary Clark06c20f32018-03-20 15:53:27 -04001797#SeeAlso bytesPerPixel minRowBytes SkBitmap::shiftPerPixel SkPixmap::shiftPerPixel
Cary Clark2dc84ad2018-01-26 12:56:22 -05001798
1799#Method ##
1800
1801# ------------------------------------------------------------------------------
1802
1803#Method uint64_t minRowBytes64() const
Cary Clark78de7512018-02-07 07:27:09 -05001804#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001805#Line # returns width() times bytesPerPixel in 64 bits ##
Cary Clark09d80c02018-10-31 12:14:03 -04001806#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001807
1808#Example
Cary Clark681287e2018-03-16 11:34:15 -04001809 for (int shift = 24; shift < 32; ++shift) {
1810 int width = 1 << shift;
Cary Clark682c58d2018-05-16 07:07:07 -04001811 SkImageInfo imageInfo =
Cary Clark681287e2018-03-16 11:34:15 -04001812 SkImageInfo::Make(width, 1, kRGBA_F16_SkColorType, kPremul_SkAlphaType);
1813 uint64_t minRowBytes = imageInfo.minRowBytes64();
1814 bool widthTooLarge = (uint64_t) (int32_t) minRowBytes != minRowBytes;
1815 SkDebugf("RGBA_F16 width %d (0x%08x) %s\n",
Cary Clark682c58d2018-05-16 07:07:07 -04001816 width, width, widthTooLarge ? "too large" : "OK");
Cary Clark681287e2018-03-16 11:34:15 -04001817 }
1818#StdOut
1819RGBA_F16 width 16777216 (0x01000000) OK
1820RGBA_F16 width 33554432 (0x02000000) OK
1821RGBA_F16 width 67108864 (0x04000000) OK
1822RGBA_F16 width 134217728 (0x08000000) OK
1823RGBA_F16 width 268435456 (0x10000000) too large
1824RGBA_F16 width 536870912 (0x20000000) too large
1825RGBA_F16 width 1073741824 (0x40000000) too large
1826RGBA_F16 width -2147483648 (0x80000000) too large
1827##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001828##
1829
Cary Clark681287e2018-03-16 11:34:15 -04001830#SeeAlso minRowBytes computeByteSize computeMinByteSize validRowBytes
Cary Clark2dc84ad2018-01-26 12:56:22 -05001831
1832#Method ##
1833
1834# ------------------------------------------------------------------------------
1835
1836#Method size_t minRowBytes() const
Cary Clark78de7512018-02-07 07:27:09 -05001837#In Property
Cary Clark681287e2018-03-16 11:34:15 -04001838#Line # returns width() times bytesPerPixel in 32 bits ##
Cary Clark09d80c02018-10-31 12:14:03 -04001839#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001840
1841#Example
Cary Clark681287e2018-03-16 11:34:15 -04001842 for (int shift = 24; shift < 32; ++shift) {
1843 int width = 1 << shift;
Cary Clark682c58d2018-05-16 07:07:07 -04001844 SkImageInfo imageInfo =
Cary Clark681287e2018-03-16 11:34:15 -04001845 SkImageInfo::Make(width, 1, kRGBA_F16_SkColorType, kPremul_SkAlphaType);
1846 size_t minRowBytes = imageInfo.minRowBytes();
1847 bool widthTooLarge = !minRowBytes;
1848 SkDebugf("RGBA_F16 width %d (0x%08x) %s\n",
Cary Clark682c58d2018-05-16 07:07:07 -04001849 width, width, widthTooLarge ? "too large" : "OK");
Cary Clark681287e2018-03-16 11:34:15 -04001850 }
1851#StdOut
1852RGBA_F16 width 16777216 (0x01000000) OK
1853RGBA_F16 width 33554432 (0x02000000) OK
1854RGBA_F16 width 67108864 (0x04000000) OK
1855RGBA_F16 width 134217728 (0x08000000) OK
1856RGBA_F16 width 268435456 (0x10000000) too large
1857RGBA_F16 width 536870912 (0x20000000) too large
1858RGBA_F16 width 1073741824 (0x40000000) too large
1859RGBA_F16 width -2147483648 (0x80000000) too large
1860##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001861##
1862
Cary Clark681287e2018-03-16 11:34:15 -04001863#SeeAlso minRowBytes64 computeByteSize computeMinByteSize validRowBytes
Cary Clark2dc84ad2018-01-26 12:56:22 -05001864
1865#Method ##
1866
1867# ------------------------------------------------------------------------------
1868
1869#Method size_t computeOffset(int x, int y, size_t rowBytes) const
Cary Clark78de7512018-02-07 07:27:09 -05001870#In Utility
Cary Clark681287e2018-03-16 11:34:15 -04001871#Line # returns byte offset within pixel array ##
Cary Clark09d80c02018-10-31 12:14:03 -04001872#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001873
1874#Example
Cary Clark06c20f32018-03-20 15:53:27 -04001875#Height 128
Cary Clark681287e2018-03-16 11:34:15 -04001876 uint8_t pixels[][12] = { { 0x00, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0x00},
1877 { 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00},
1878 { 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00},
1879 { 0xFF, 0xFF, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0xFF},
1880 { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF},
1881 { 0x00, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0x00, 0x00},
1882 { 0x00, 0xFF, 0x00, 0x00, 0x00, 0x00, 0xFF, 0x00},
1883 { 0x00, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0x00, 0x00} };
1884 SkImageInfo imageInfo = SkImageInfo::MakeA8(8, 8);
1885 SkBitmap bitmap;
1886 bitmap.installPixels(imageInfo, (void*) pixels, sizeof(pixels[0]));
1887 SkPaint paint;
1888 paint.setColor(SK_ColorRED);
1889 canvas->drawBitmapRect(bitmap, SkRect::MakeWH(8, 8), SkRect::MakeWH(32, 32), &paint);
1890 size_t offset = imageInfo.computeOffset(2, 3, sizeof(pixels[0]));
1891 pixels[0][offset] = 0x7F;
1892 offset = imageInfo.computeOffset(5, 3, sizeof(pixels[0]));
1893 pixels[0][offset] = 0x7F;
1894 bitmap.installPixels(imageInfo, (void*) pixels, sizeof(pixels[0]));
1895 canvas->drawBitmapRect(bitmap, SkRect::MakeWH(8, 8), SkRect::MakeWH(128, 128), &paint);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001896##
1897
Cary Clark06c20f32018-03-20 15:53:27 -04001898#SeeAlso height width minRowBytes computeByteSize
Cary Clark2dc84ad2018-01-26 12:56:22 -05001899
1900#Method ##
1901
1902# ------------------------------------------------------------------------------
1903
Cary Clarkcb6bef02018-11-29 12:05:25 -05001904#Method bool operator==(const SkImageInfo& other) const
Cary Clark06c20f32018-03-20 15:53:27 -04001905#Line # compares Image_Info for equality ##
Cary Clark09d80c02018-10-31 12:14:03 -04001906#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001907
1908#Example
Cary Clark682c58d2018-05-16 07:07:07 -04001909 SkImageInfo info1 = SkImageInfo::Make(10, 20, kGray_8_SkColorType, kPremul_SkAlphaType);
1910 SkImageInfo info2 = SkImageInfo::Make(20, 10, kAlpha_8_SkColorType, kUnpremul_SkAlphaType);
1911 SkDebugf("info1 %c= info2\n", info1 == info2 ? '=' : '!');
1912 info2 = info2.makeWH(10, 20);
1913 SkDebugf("info1 %c= info2\n", info1 == info2 ? '=' : '!');
1914 info2 = info2.makeColorType(kGray_8_SkColorType);
1915 SkDebugf("info1 %c= info2\n", info1 == info2 ? '=' : '!');
1916 info2 = info2.makeAlphaType(kPremul_SkAlphaType);
1917 SkDebugf("info1 %c= info2\n", info1 == info2 ? '=' : '!');
1918#StdOut
1919info1 != info2
1920info1 != info2
1921info1 != info2
1922info1 == info2
1923##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001924##
1925
Cary Clarkcb6bef02018-11-29 12:05:25 -05001926#SeeAlso operator!=(const SkImageInfo& other) const SkColorSpace::Equals
Cary Clark2dc84ad2018-01-26 12:56:22 -05001927
1928#Method ##
1929
1930# ------------------------------------------------------------------------------
1931
Cary Clarkcb6bef02018-11-29 12:05:25 -05001932#Method bool operator!=(const SkImageInfo& other) const
Cary Clark06c20f32018-03-20 15:53:27 -04001933#Line # compares Image_Info for inequality ##
Cary Clark09d80c02018-10-31 12:14:03 -04001934#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001935
1936#Example
Cary Clark682c58d2018-05-16 07:07:07 -04001937 SkImageInfo info1 = SkImageInfo::Make(10, 20, kGray_8_SkColorType, kPremul_SkAlphaType);
1938 SkImageInfo info2 = SkImageInfo::Make(20, 10, kAlpha_8_SkColorType, kUnpremul_SkAlphaType);
1939 SkDebugf("info1 %c= info2\n", info1 != info2 ? '!' : '=');
1940 info2 = info2.makeWH(10, 20);
1941 SkDebugf("info1 %c= info2\n", info1 != info2 ? '!' : '=');
1942 info2 = info2.makeColorType(kGray_8_SkColorType);
1943 SkDebugf("info1 %c= info2\n", info1 != info2 ? '!' : '=');
1944 info2 = info2.makeAlphaType(kPremul_SkAlphaType);
1945 SkDebugf("info1 %c= info2\n", info1 != info2 ? '!' : '=');
1946#StdOut
1947info1 != info2
1948info1 != info2
1949info1 != info2
1950info1 == info2
1951##
Cary Clark2dc84ad2018-01-26 12:56:22 -05001952##
1953
Cary Clarkcb6bef02018-11-29 12:05:25 -05001954#SeeAlso operator==(const SkImageInfo& other) const SkColorSpace::Equals
Cary Clark2dc84ad2018-01-26 12:56:22 -05001955
1956#Method ##
1957
1958# ------------------------------------------------------------------------------
1959
1960#Method size_t computeByteSize(size_t rowBytes) const
Cary Clark78de7512018-02-07 07:27:09 -05001961#In Utility
Cary Clark682c58d2018-05-16 07:07:07 -04001962#Line # returns memory required by pixel buffer with given row bytes ##
Cary Clark09d80c02018-10-31 12:14:03 -04001963#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001964
1965#Example
Cary Clark06c20f32018-03-20 15:53:27 -04001966#Height 130
Cary Clark682c58d2018-05-16 07:07:07 -04001967 SkImageInfo info = SkImageInfo::MakeN32Premul(2, 2);
1968 const size_t size = info.computeByteSize(100000);
1969 SkAutoTMalloc<SkPMColor> storage(size);
1970 SkPMColor* pixels = storage.get();
1971 SkBitmap bitmap;
1972 bitmap.setInfo(info);
1973 bitmap.setPixels(pixels);
1974 bitmap.eraseColor(SK_ColorRED);
1975 canvas->scale(50, 50);
1976 canvas->rotate(8);
Cary Clark06c20f32018-03-20 15:53:27 -04001977 canvas->drawBitmap(bitmap, 2, 0);
Cary Clark2dc84ad2018-01-26 12:56:22 -05001978##
1979
Cary Clark06c20f32018-03-20 15:53:27 -04001980#SeeAlso computeMinByteSize validRowBytes
Cary Clark2dc84ad2018-01-26 12:56:22 -05001981
1982#Method ##
1983
1984# ------------------------------------------------------------------------------
1985
1986#Method size_t computeMinByteSize() const
Cary Clark78de7512018-02-07 07:27:09 -05001987#In Utility
Cary Clark682c58d2018-05-16 07:07:07 -04001988#Line # returns least memory required by pixel buffer ##
Cary Clark09d80c02018-10-31 12:14:03 -04001989#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05001990
1991#Example
Cary Clark06c20f32018-03-20 15:53:27 -04001992#Height 130
Cary Clark682c58d2018-05-16 07:07:07 -04001993 SkImageInfo info = SkImageInfo::MakeN32Premul(2, 2);
1994 const size_t size = info.computeMinByteSize();
1995 SkAutoTMalloc<SkPMColor> storage(size);
1996 SkPMColor* pixels = storage.get();
1997 SkBitmap bitmap;
1998 bitmap.setInfo(info);
1999 bitmap.setPixels(pixels);
2000 bitmap.eraseColor(SK_ColorRED);
2001 canvas->scale(50, 50);
2002 canvas->rotate(8);
Cary Clark06c20f32018-03-20 15:53:27 -04002003 canvas->drawBitmap(bitmap, 2, 0);
Cary Clark2dc84ad2018-01-26 12:56:22 -05002004##
2005
Cary Clark06c20f32018-03-20 15:53:27 -04002006#SeeAlso computeByteSize validRowBytes
Cary Clark2dc84ad2018-01-26 12:56:22 -05002007
2008#Method ##
2009
2010# ------------------------------------------------------------------------------
2011
2012#Method static bool ByteSizeOverflowed(size_t byteSize)
Cary Clark78de7512018-02-07 07:27:09 -05002013#In Utility
Cary Clark06c20f32018-03-20 15:53:27 -04002014#Line # checks result of computeByteSize and computeMinByteSize ##
Cary Clark09d80c02018-10-31 12:14:03 -04002015#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05002016
2017#Example
Cary Clark682c58d2018-05-16 07:07:07 -04002018 SkImageInfo info = SkImageInfo::MakeN32Premul(2, 1000000000);
2019 for (size_t rowBytes = 100000000; rowBytes < 10000000000000LL; rowBytes *= 10) {
2020 const size_t size = info.computeByteSize(rowBytes);
2021 SkDebugf("rowBytes:%llu size:%llu overflowed:%s\n", rowBytes, size,
2022 SkImageInfo::ByteSizeOverflowed(size) ? "true" : "false");
2023 }
2024#StdOut
2025rowBytes:100000000 size:99999999900000008 overflowed:false
2026rowBytes:1000000000 size:999999999000000008 overflowed:false
2027rowBytes:10000000000 size:9999999990000000008 overflowed:false
2028rowBytes:100000000000 size:18446744073709551615 overflowed:true
2029rowBytes:1000000000000 size:18446744073709551615 overflowed:true
2030##
Cary Clark2dc84ad2018-01-26 12:56:22 -05002031##
2032
Cary Clark06c20f32018-03-20 15:53:27 -04002033#SeeAlso computeByteSize computeMinByteSize validRowBytes
Cary Clark2dc84ad2018-01-26 12:56:22 -05002034
2035#Method ##
2036
2037# ------------------------------------------------------------------------------
2038
2039#Method bool validRowBytes(size_t rowBytes) const
Cary Clark78de7512018-02-07 07:27:09 -05002040#In Utility
Cary Clark06c20f32018-03-20 15:53:27 -04002041#Line # checks if row bytes is large enough to contain pixel row ##
Cary Clark09d80c02018-10-31 12:14:03 -04002042#Populate
Cary Clark2dc84ad2018-01-26 12:56:22 -05002043
2044#Example
Cary Clark682c58d2018-05-16 07:07:07 -04002045 SkImageInfo info = SkImageInfo::MakeN32Premul(16, 8);
2046 for (size_t rowBytes = 60; rowBytes < 72; rowBytes += sizeof(SkPMColor)) {
2047 SkDebugf("validRowBytes(%llu): %s\n", rowBytes, info.validRowBytes(rowBytes) ?
2048 "true" : "false");
2049 }
2050#StdOut
2051validRowBytes(60): false
2052validRowBytes(64): true
2053validRowBytes(68): true
2054##
Cary Clark2dc84ad2018-01-26 12:56:22 -05002055##
2056
Cary Clark06c20f32018-03-20 15:53:27 -04002057#SeeAlso ByteSizeOverflowed computeByteSize computeMinByteSize
Cary Clark2dc84ad2018-01-26 12:56:22 -05002058
2059#Method ##
2060
2061# ------------------------------------------------------------------------------
2062
2063#Method void reset()
Cary Clark61313f32018-10-08 14:57:48 -04002064#In Constructors
Cary Clark06c20f32018-03-20 15:53:27 -04002065#Line # sets zero dimensions, kUnknown_SkColorType, kUnknown_SkAlphaType ##
Cary Clark09d80c02018-10-31 12:14:03 -04002066#Populate
Cary Clark06c20f32018-03-20 15:53:27 -04002067
Cary Clark2dc84ad2018-01-26 12:56:22 -05002068#Example
Cary Clark682c58d2018-05-16 07:07:07 -04002069 SkImageInfo info = SkImageInfo::MakeN32Premul(16, 8);
2070 SkImageInfo copy = info;
2071 SkDebugf("info %c= copy\n", info == copy ? '=' : '!');
2072 copy.reset();
2073 SkDebugf("info %c= reset copy\n", info == copy ? '=' : '!');
2074 SkDebugf("SkImageInfo() %c= reset copy\n", SkImageInfo() == copy ? '=' : '!');
2075#StdOut
2076info == copy
2077info != reset copy
2078SkImageInfo() == reset copy
2079##
Cary Clark2dc84ad2018-01-26 12:56:22 -05002080##
2081
Cary Clark06c20f32018-03-20 15:53:27 -04002082#SeeAlso SkImageInfo()
Cary Clark2dc84ad2018-01-26 12:56:22 -05002083
2084#Method ##
2085
2086# ------------------------------------------------------------------------------
Cary Clark78de7512018-02-07 07:27:09 -05002087#Subtopic Utility
Cary Clark78de7512018-02-07 07:27:09 -05002088#Line # rarely called management functions ##
2089##
Cary Clark2dc84ad2018-01-26 12:56:22 -05002090
2091#Method void validate() const
Cary Clark78de7512018-02-07 07:27:09 -05002092#In Utility
Cary Clark06c20f32018-03-20 15:53:27 -04002093#Line # asserts if Image_Info is invalid (debug only) ##
Cary Clark09d80c02018-10-31 12:14:03 -04002094#Populate
Cary Clark06c20f32018-03-20 15:53:27 -04002095
2096#NoExample
Cary Clark2dc84ad2018-01-26 12:56:22 -05002097##
2098
Cary Clark06c20f32018-03-20 15:53:27 -04002099#SeeAlso validRowBytes SkBitmap::validate
Cary Clark2dc84ad2018-01-26 12:56:22 -05002100
2101#Method ##
2102
2103#Struct SkImageInfo ##
2104
Cary Clark08895c42018-02-01 09:37:32 -05002105#Topic Image_Info ##