reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 1 | /* libs/graphics/sgl/SkBlitter_ARGB32.cpp |
| 2 | ** |
| 3 | ** Copyright 2006, The Android Open Source Project |
| 4 | ** |
| 5 | ** Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | ** you may not use this file except in compliance with the License. |
| 7 | ** You may obtain a copy of the License at |
| 8 | ** |
| 9 | ** http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | ** |
| 11 | ** Unless required by applicable law or agreed to in writing, software |
| 12 | ** distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | ** See the License for the specific language governing permissions and |
| 15 | ** limitations under the License. |
| 16 | */ |
| 17 | |
| 18 | #include "SkCoreBlitters.h" |
| 19 | #include "SkColorPriv.h" |
| 20 | #include "SkDither.h" |
| 21 | #include "SkShader.h" |
| 22 | #include "SkTemplatesPriv.h" |
| 23 | #include "SkUtils.h" |
| 24 | #include "SkXfermode.h" |
| 25 | |
| 26 | inline SkPMColor SkBlendARGB4444(SkPMColor16 src, SkPMColor16 dst, U8CPU aa) |
| 27 | { |
| 28 | SkASSERT((unsigned)aa <= 255); |
| 29 | |
| 30 | unsigned src_scale = SkAlpha255To256(aa) >> 4; |
| 31 | unsigned dst_scale = SkAlpha15To16(15 - SkAlphaMul4(SkGetPackedA4444(src), src_scale)); |
| 32 | |
| 33 | uint32_t src32 = SkExpand_4444(src) * src_scale; |
| 34 | uint32_t dst32 = SkExpand_4444(dst) * dst_scale; |
| 35 | return SkCompact_4444((src32 + dst32) >> 4); |
| 36 | } |
| 37 | |
| 38 | /////////////////////////////////////////////////////////////////////////////// |
| 39 | |
| 40 | class SkARGB4444_Blitter : public SkRasterBlitter { |
| 41 | public: |
| 42 | SkARGB4444_Blitter(const SkBitmap& device, const SkPaint& paint); |
| 43 | virtual void blitH(int x, int y, int width); |
| 44 | virtual void blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[]); |
| 45 | virtual void blitV(int x, int y, int height, SkAlpha alpha); |
| 46 | virtual void blitRect(int x, int y, int width, int height); |
| 47 | virtual void blitMask(const SkMask&, const SkIRect&); |
| 48 | virtual const SkBitmap* justAnOpaqueColor(uint32_t*); |
| 49 | |
| 50 | protected: |
| 51 | SkPMColor16 fPMColor16, fPMColor16Other; |
| 52 | SkPMColor16 fRawColor16, fRawColor16Other; |
| 53 | uint8_t fScale16; |
| 54 | |
| 55 | private: |
| 56 | // illegal |
| 57 | SkARGB4444_Blitter& operator=(const SkARGB4444_Blitter&); |
| 58 | |
| 59 | typedef SkRasterBlitter INHERITED; |
| 60 | }; |
| 61 | |
| 62 | |
| 63 | SkARGB4444_Blitter::SkARGB4444_Blitter(const SkBitmap& device, const SkPaint& paint) |
| 64 | : INHERITED(device) |
| 65 | { |
| 66 | // cache premultiplied versions in 4444 |
| 67 | SkPMColor c = SkPreMultiplyColor(paint.getColor()); |
| 68 | fPMColor16 = SkPixel32ToPixel4444(c); |
| 69 | if (paint.isDither()) { |
| 70 | fPMColor16Other = SkDitherPixel32To4444(c); |
| 71 | } else { |
| 72 | fPMColor16Other = fPMColor16; |
| 73 | } |
| 74 | |
| 75 | // cache raw versions in 4444 |
| 76 | fRawColor16 = SkPackARGB4444(0xFF >> 4, SkColorGetR(c) >> 4, |
| 77 | SkColorGetG(c) >> 4, SkColorGetB(c) >> 4); |
| 78 | if (paint.isDither()) { |
| 79 | fRawColor16Other = SkDitherARGB32To4444(0xFF, SkColorGetR(c), |
| 80 | SkColorGetG(c), SkColorGetB(c)); |
| 81 | } else { |
| 82 | fRawColor16Other = fRawColor16; |
| 83 | } |
| 84 | |
| 85 | // our dithered color will be the same or more opaque than the original |
| 86 | // so use dithered to compute our scale |
| 87 | SkASSERT(SkGetPackedA4444(fPMColor16Other) >= SkGetPackedA4444(fPMColor16)); |
| 88 | |
| 89 | fScale16 = SkAlpha15To16(SkGetPackedA4444(fPMColor16Other)); |
| 90 | if (16 == fScale16) { |
| 91 | // force the original to also be opaque |
| 92 | fPMColor16 |= (0xF << SK_A4444_SHIFT); |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | const SkBitmap* SkARGB4444_Blitter::justAnOpaqueColor(uint32_t* value) |
| 97 | { |
| 98 | if (16 == fScale16) { |
| 99 | *value = fPMColor16; |
| 100 | return &fDevice; |
| 101 | } |
| 102 | return NULL; |
| 103 | } |
| 104 | |
| 105 | static void src_over_4444(SkPMColor16 dst[], SkPMColor16 color, |
| 106 | SkPMColor16 other, unsigned invScale, int count) |
| 107 | { |
| 108 | int twice = count >> 1; |
| 109 | while (--twice >= 0) { |
| 110 | *dst = color + SkAlphaMulQ4(*dst, invScale); |
| 111 | dst++; |
| 112 | *dst = other + SkAlphaMulQ4(*dst, invScale); |
| 113 | dst++; |
| 114 | } |
reed@android.com | b602b8e | 2009-07-10 15:58:53 +0000 | [diff] [blame^] | 115 | if (count & 1) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 116 | *dst = color + SkAlphaMulQ4(*dst, invScale); |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | static inline uint32_t SkExpand_4444_Replicate(SkPMColor16 c) |
| 121 | { |
| 122 | uint32_t c32 = SkExpand_4444(c); |
| 123 | return c32 | (c32 << 4); |
| 124 | } |
| 125 | |
| 126 | static void src_over_4444x(SkPMColor16 dst[], uint32_t color, |
| 127 | uint32_t other, unsigned invScale, int count) |
| 128 | { |
| 129 | int twice = count >> 1; |
| 130 | uint32_t tmp; |
| 131 | while (--twice >= 0) { |
| 132 | tmp = SkExpand_4444(*dst) * invScale; |
| 133 | *dst++ = SkCompact_4444((color + tmp) >> 4); |
| 134 | tmp = SkExpand_4444(*dst) * invScale; |
| 135 | *dst++ = SkCompact_4444((other + tmp) >> 4); |
| 136 | } |
reed@android.com | b602b8e | 2009-07-10 15:58:53 +0000 | [diff] [blame^] | 137 | if (count & 1) { |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 138 | tmp = SkExpand_4444(*dst) * invScale; |
| 139 | *dst = SkCompact_4444((color + tmp) >> 4); |
| 140 | } |
| 141 | } |
| 142 | |
| 143 | void SkARGB4444_Blitter::blitH(int x, int y, int width) |
| 144 | { |
| 145 | SkASSERT(x >= 0 && y >= 0 && x + width <= fDevice.width()); |
| 146 | |
| 147 | if (0 == fScale16) { |
| 148 | return; |
| 149 | } |
| 150 | |
| 151 | SkPMColor16* device = fDevice.getAddr16(x, y); |
| 152 | SkPMColor16 color = fPMColor16; |
| 153 | SkPMColor16 other = fPMColor16Other; |
| 154 | |
| 155 | if ((x ^ y) & 1) { |
| 156 | SkTSwap<SkPMColor16>(color, other); |
| 157 | } |
| 158 | |
| 159 | if (16 == fScale16) { |
| 160 | sk_dither_memset16(device, color, other, width); |
| 161 | } |
| 162 | else { |
| 163 | src_over_4444x(device, SkExpand_4444_Replicate(color), |
| 164 | SkExpand_4444_Replicate(other), |
| 165 | 16 - fScale16, width); |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | void SkARGB4444_Blitter::blitV(int x, int y, int height, SkAlpha alpha) |
| 170 | { |
| 171 | if (0 == alpha || 0 == fScale16) { |
| 172 | return; |
| 173 | } |
| 174 | |
| 175 | SkPMColor16* device = fDevice.getAddr16(x, y); |
| 176 | SkPMColor16 color = fPMColor16; |
| 177 | SkPMColor16 other = fPMColor16Other; |
| 178 | unsigned rb = fDevice.rowBytes(); |
| 179 | |
| 180 | if ((x ^ y) & 1) { |
| 181 | SkTSwap<SkPMColor16>(color, other); |
| 182 | } |
| 183 | |
| 184 | if (16 == fScale16 && 255 == alpha) { |
| 185 | while (--height >= 0) { |
| 186 | *device = color; |
| 187 | device = (SkPMColor16*)((char*)device + rb); |
| 188 | SkTSwap<SkPMColor16>(color, other); |
| 189 | } |
| 190 | } else { |
| 191 | unsigned alphaScale = SkAlpha255To256(alpha); |
| 192 | uint32_t c32 = SkExpand_4444(color) * (alphaScale >> 4); |
| 193 | // need to normalize the low nibble of each expanded component |
| 194 | // so we don't overflow the add with d32 |
| 195 | c32 = SkCompact_4444(c32 >> 4); |
| 196 | unsigned invScale = 16 - SkAlpha15To16(SkGetPackedA4444(c32)); |
| 197 | // now re-expand and replicate |
| 198 | c32 = SkExpand_4444_Replicate(c32); |
| 199 | |
| 200 | while (--height >= 0) { |
| 201 | uint32_t d32 = SkExpand_4444(*device) * invScale; |
| 202 | *device = SkCompact_4444((c32 + d32) >> 4); |
| 203 | device = (SkPMColor16*)((char*)device + rb); |
| 204 | } |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | void SkARGB4444_Blitter::blitRect(int x, int y, int width, int height) |
| 209 | { |
| 210 | SkASSERT(x >= 0 && y >= 0 && x + width <= fDevice.width() && y + height <= fDevice.height()); |
| 211 | |
| 212 | if (0 == fScale16) { |
| 213 | return; |
| 214 | } |
| 215 | |
| 216 | SkPMColor16* device = fDevice.getAddr16(x, y); |
| 217 | SkPMColor16 color = fPMColor16; |
| 218 | SkPMColor16 other = fPMColor16Other; |
| 219 | |
| 220 | if ((x ^ y) & 1) { |
| 221 | SkTSwap<SkPMColor16>(color, other); |
| 222 | } |
| 223 | |
| 224 | if (16 == fScale16) { |
| 225 | while (--height >= 0) { |
| 226 | sk_dither_memset16(device, color, other, width); |
| 227 | device = (SkPMColor16*)((char*)device + fDevice.rowBytes()); |
| 228 | SkTSwap<SkPMColor16>(color, other); |
| 229 | } |
| 230 | } else { |
| 231 | unsigned invScale = 16 - fScale16; |
| 232 | |
| 233 | uint32_t c32 = SkExpand_4444_Replicate(color); |
| 234 | uint32_t o32 = SkExpand_4444_Replicate(other); |
| 235 | while (--height >= 0) { |
| 236 | src_over_4444x(device, c32, o32, invScale, width); |
| 237 | device = (SkPMColor16*)((char*)device + fDevice.rowBytes()); |
| 238 | SkTSwap<uint32_t>(c32, o32); |
| 239 | } |
| 240 | } |
| 241 | } |
| 242 | |
| 243 | void SkARGB4444_Blitter::blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[]) |
| 244 | { |
| 245 | if (0 == fScale16) { |
| 246 | return; |
| 247 | } |
| 248 | |
| 249 | SkPMColor16* device = fDevice.getAddr16(x, y); |
| 250 | SkPMColor16 color = fPMColor16; |
| 251 | SkPMColor16 other = fPMColor16Other; |
| 252 | |
| 253 | if ((x ^ y) & 1) { |
| 254 | SkTSwap<SkPMColor16>(color, other); |
| 255 | } |
| 256 | |
| 257 | for (;;) { |
| 258 | int count = runs[0]; |
| 259 | SkASSERT(count >= 0); |
| 260 | if (count <= 0) { |
| 261 | return; |
| 262 | } |
| 263 | |
| 264 | unsigned aa = antialias[0]; |
| 265 | if (aa) { |
| 266 | if (0xFF == aa) { |
| 267 | if (16 == fScale16) { |
| 268 | sk_dither_memset16(device, color, other, count); |
| 269 | } else { |
| 270 | src_over_4444(device, color, other, 16 - fScale16, count); |
| 271 | } |
| 272 | } else { |
| 273 | // todo: respect dithering |
| 274 | aa = SkAlpha255To256(aa); // FIX |
| 275 | SkPMColor16 src = SkAlphaMulQ4(color, aa >> 4); |
| 276 | unsigned dst_scale = SkAlpha15To16(15 - SkGetPackedA4444(src)); // FIX |
| 277 | int n = count; |
| 278 | do { |
| 279 | --n; |
| 280 | device[n] = src + SkAlphaMulQ4(device[n], dst_scale); |
| 281 | } while (n > 0); |
| 282 | } |
| 283 | } |
| 284 | |
| 285 | runs += count; |
| 286 | antialias += count; |
| 287 | device += count; |
| 288 | |
| 289 | if (count & 1) { |
| 290 | SkTSwap<SkPMColor16>(color, other); |
| 291 | } |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | ////////////////////////////////////////////////////////////////////////////////////// |
| 296 | |
| 297 | #define solid_8_pixels(mask, dst, color) \ |
| 298 | do { \ |
| 299 | if (mask & 0x80) dst[0] = color; \ |
| 300 | if (mask & 0x40) dst[1] = color; \ |
| 301 | if (mask & 0x20) dst[2] = color; \ |
| 302 | if (mask & 0x10) dst[3] = color; \ |
| 303 | if (mask & 0x08) dst[4] = color; \ |
| 304 | if (mask & 0x04) dst[5] = color; \ |
| 305 | if (mask & 0x02) dst[6] = color; \ |
| 306 | if (mask & 0x01) dst[7] = color; \ |
| 307 | } while (0) |
| 308 | |
| 309 | #define SK_BLITBWMASK_NAME SkARGB4444_BlitBW |
| 310 | #define SK_BLITBWMASK_ARGS , SkPMColor16 color |
| 311 | #define SK_BLITBWMASK_BLIT8(mask, dst) solid_8_pixels(mask, dst, color) |
| 312 | #define SK_BLITBWMASK_GETADDR getAddr16 |
| 313 | #define SK_BLITBWMASK_DEVTYPE uint16_t |
| 314 | #include "SkBlitBWMaskTemplate.h" |
| 315 | |
| 316 | #define blend_8_pixels(mask, dst, sc, dst_scale) \ |
| 317 | do { \ |
| 318 | if (mask & 0x80) { dst[0] = sc + SkAlphaMulQ4(dst[0], dst_scale); } \ |
| 319 | if (mask & 0x40) { dst[1] = sc + SkAlphaMulQ4(dst[1], dst_scale); } \ |
| 320 | if (mask & 0x20) { dst[2] = sc + SkAlphaMulQ4(dst[2], dst_scale); } \ |
| 321 | if (mask & 0x10) { dst[3] = sc + SkAlphaMulQ4(dst[3], dst_scale); } \ |
| 322 | if (mask & 0x08) { dst[4] = sc + SkAlphaMulQ4(dst[4], dst_scale); } \ |
| 323 | if (mask & 0x04) { dst[5] = sc + SkAlphaMulQ4(dst[5], dst_scale); } \ |
| 324 | if (mask & 0x02) { dst[6] = sc + SkAlphaMulQ4(dst[6], dst_scale); } \ |
| 325 | if (mask & 0x01) { dst[7] = sc + SkAlphaMulQ4(dst[7], dst_scale); } \ |
| 326 | } while (0) |
| 327 | |
| 328 | #define SK_BLITBWMASK_NAME SkARGB4444_BlendBW |
| 329 | #define SK_BLITBWMASK_ARGS , uint16_t sc, unsigned dst_scale |
| 330 | #define SK_BLITBWMASK_BLIT8(mask, dst) blend_8_pixels(mask, dst, sc, dst_scale) |
| 331 | #define SK_BLITBWMASK_GETADDR getAddr16 |
| 332 | #define SK_BLITBWMASK_DEVTYPE uint16_t |
| 333 | #include "SkBlitBWMaskTemplate.h" |
| 334 | |
| 335 | void SkARGB4444_Blitter::blitMask(const SkMask& mask, const SkIRect& clip) |
| 336 | { |
| 337 | SkASSERT(mask.fBounds.contains(clip)); |
| 338 | |
| 339 | if (0 == fScale16) { |
| 340 | return; |
| 341 | } |
| 342 | |
| 343 | if (mask.fFormat == SkMask::kBW_Format) { |
| 344 | if (16 == fScale16) { |
| 345 | SkARGB4444_BlitBW(fDevice, mask, clip, fPMColor16); |
| 346 | } else { |
| 347 | SkARGB4444_BlendBW(fDevice, mask, clip, fPMColor16, 16 - fScale16); |
| 348 | } |
| 349 | return; |
| 350 | } |
| 351 | |
| 352 | int x = clip.fLeft; |
| 353 | int y = clip.fTop; |
| 354 | int width = clip.width(); |
| 355 | int height = clip.height(); |
| 356 | |
| 357 | SkPMColor16* device = fDevice.getAddr16(x, y); |
| 358 | const uint8_t* alpha = mask.getAddr(x, y); |
| 359 | SkPMColor16 srcColor = fPMColor16; |
| 360 | unsigned devRB = fDevice.rowBytes() - (width << 1); |
| 361 | unsigned maskRB = mask.fRowBytes - width; |
| 362 | |
| 363 | do { |
| 364 | int w = width; |
| 365 | do { |
| 366 | unsigned aa = *alpha++; |
| 367 | *device = SkBlendARGB4444(srcColor, *device, aa); |
| 368 | device += 1; |
| 369 | } while (--w != 0); |
| 370 | device = (SkPMColor16*)((char*)device + devRB); |
| 371 | alpha += maskRB; |
| 372 | } while (--height != 0); |
| 373 | } |
| 374 | |
| 375 | ////////////////////////////////////////////////////////////////////////////////////////// |
| 376 | |
| 377 | class SkARGB4444_Shader_Blitter : public SkShaderBlitter { |
| 378 | SkXfermode* fXfermode; |
| 379 | SkBlitRow::Proc fOpaqueProc; |
| 380 | SkBlitRow::Proc fAlphaProc; |
| 381 | SkPMColor* fBuffer; |
| 382 | uint8_t* fAAExpand; |
| 383 | public: |
| 384 | SkARGB4444_Shader_Blitter(const SkBitmap& device, const SkPaint& paint) |
| 385 | : INHERITED(device, paint) |
| 386 | { |
| 387 | const int width = device.width(); |
| 388 | fBuffer = (SkPMColor*)sk_malloc_throw(width * sizeof(SkPMColor) + width); |
| 389 | fAAExpand = (uint8_t*)(fBuffer + width); |
| 390 | |
| 391 | (fXfermode = paint.getXfermode())->safeRef(); |
| 392 | |
| 393 | unsigned flags = 0; |
| 394 | if (!(fShader->getFlags() & SkShader::kOpaqueAlpha_Flag)) { |
| 395 | flags |= SkBlitRow::kSrcPixelAlpha_Flag; |
| 396 | } |
| 397 | if (paint.isDither()) { |
| 398 | flags |= SkBlitRow::kDither_Flag; |
| 399 | } |
| 400 | fOpaqueProc = SkBlitRow::Factory(flags, SkBitmap::kARGB_4444_Config); |
| 401 | fAlphaProc = SkBlitRow::Factory(flags | SkBlitRow::kGlobalAlpha_Flag, |
| 402 | SkBitmap::kARGB_4444_Config); |
| 403 | } |
| 404 | |
| 405 | virtual ~SkARGB4444_Shader_Blitter() |
| 406 | { |
| 407 | fXfermode->safeUnref(); |
| 408 | sk_free(fBuffer); |
| 409 | } |
| 410 | |
| 411 | virtual void blitH(int x, int y, int width) |
| 412 | { |
| 413 | SkASSERT(x >= 0 && y >= 0 && x + width <= fDevice.width()); |
| 414 | |
| 415 | SkPMColor16* device = fDevice.getAddr16(x, y); |
| 416 | SkPMColor* span = fBuffer; |
| 417 | |
| 418 | fShader->shadeSpan(x, y, span, width); |
| 419 | if (fXfermode) { |
| 420 | fXfermode->xfer4444(device, span, width, NULL); |
| 421 | } |
| 422 | else { |
| 423 | fOpaqueProc(device, span, width, 0xFF, x, y); |
| 424 | } |
| 425 | } |
| 426 | |
| 427 | virtual void blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[]) |
| 428 | { |
| 429 | SkPMColor* SK_RESTRICT span = fBuffer; |
| 430 | uint8_t* SK_RESTRICT aaExpand = fAAExpand; |
| 431 | SkPMColor16* device = fDevice.getAddr16(x, y); |
| 432 | SkShader* shader = fShader; |
| 433 | SkXfermode* xfer = fXfermode; |
| 434 | |
| 435 | if (NULL != xfer) { |
| 436 | for (;;) { |
| 437 | int count = *runs; |
| 438 | if (count <= 0) |
| 439 | break; |
| 440 | int aa = *antialias; |
| 441 | if (aa) { |
| 442 | shader->shadeSpan(x, y, span, count); |
| 443 | if (255 == aa) { |
| 444 | xfer->xfer4444(device, span, count, NULL); |
| 445 | } else { |
| 446 | const uint8_t* aaBuffer = antialias; |
| 447 | if (count > 1) { |
| 448 | memset(aaExpand, aa, count); |
| 449 | aaBuffer = aaExpand; |
| 450 | } |
| 451 | xfer->xfer4444(device, span, count, aaBuffer); |
| 452 | } |
| 453 | } |
| 454 | device += count; |
| 455 | runs += count; |
| 456 | antialias += count; |
| 457 | x += count; |
| 458 | } |
| 459 | } else { // no xfermode |
| 460 | for (;;) { |
| 461 | int count = *runs; |
| 462 | if (count <= 0) |
| 463 | break; |
| 464 | int aa = *antialias; |
| 465 | if (aa) { |
| 466 | fShader->shadeSpan(x, y, span, count); |
| 467 | if (255 == aa) { |
| 468 | fOpaqueProc(device, span, count, aa, x, y); |
| 469 | } else { |
| 470 | fAlphaProc(device, span, count, aa, x, y); |
| 471 | } |
| 472 | } |
| 473 | device += count; |
| 474 | runs += count; |
| 475 | antialias += count; |
| 476 | x += count; |
| 477 | } |
| 478 | } |
| 479 | } |
| 480 | |
| 481 | private: |
| 482 | typedef SkShaderBlitter INHERITED; |
| 483 | }; |
| 484 | |
| 485 | /////////////////////////////////////////////////////////////////////////////// |
| 486 | /////////////////////////////////////////////////////////////////////////////// |
| 487 | |
| 488 | SkBlitter* SkBlitter_ChooseD4444(const SkBitmap& device, |
| 489 | const SkPaint& paint, |
| 490 | void* storage, size_t storageSize) |
| 491 | { |
| 492 | SkBlitter* blitter; |
| 493 | |
| 494 | if (paint.getShader()) { |
| 495 | SK_PLACEMENT_NEW_ARGS(blitter, SkARGB4444_Shader_Blitter, storage, storageSize, (device, paint)); |
| 496 | } else { |
| 497 | SK_PLACEMENT_NEW_ARGS(blitter, SkARGB4444_Blitter, storage, storageSize, (device, paint)); |
| 498 | } |
| 499 | return blitter; |
| 500 | } |
| 501 | |