| #Topic Text_Blob |
| #Alias Text_Blob_Reference ## |
| |
| #PhraseDef paint_font_metrics |
| Typeface, Paint_Text_Size, Paint_Text_Scale_X, |
| Paint_Text_Skew_X, Paint_Text_Align, Paint_Hinting, Anti_Alias, Paint_Fake_Bold, |
| Font_Embedded_Bitmaps, Full_Hinting_Spacing, LCD_Text, Linear_Text, |
| and Subpixel_Text |
| ## |
| |
| Text_Blob holds one or more runs of text. Each run associates a string of Glyphs |
| with a position and Paint. Each Paint contains attributes used |
| to define the run text: #paint_font_metrics#. |
| |
| Text_Blob runs of text use Glyph_ID encoding; each run Paint must set |
| Paint_Text_Encoding to SkPaint::kGlyphID_TextEncoding. |
| |
| Text_Blob is constructed with SkTextBlob::MakeFromText or Text_Blob_Builder. |
| Once created, Text_Blob can not be modified. |
| |
| #Subtopic Overview |
| #Populate |
| ## |
| |
| #Subtopic Constructor |
| #Populate |
| ## |
| |
| #Subtopic Member_Function |
| #Populate |
| ## |
| |
| # ------------------------------------------------------------------------------ |
| |
| #Class SkTextBlob |
| |
| SkTextBlob combines multiple text runs into an immutable container. Each text |
| run consists of Glyphs, Paint, and position. Only parts of Paint related to |
| fonts and text rendering are used by run. |
| |
| # ------------------------------------------------------------------------------ |
| |
| #Method const SkRect& bounds() const |
| #In Property |
| #Line # returns conservative bounding box ## |
| |
| Returns conservative bounding box. Uses Paint associated with each glyph to |
| determine glyph bounds, and unions all bounds. Returned bounds may be |
| larger than the bounds of all Glyphs in runs. |
| |
| #Return conservative bounding box ## |
| |
| #Example |
| #Height 70 |
| SkTextBlobBuilder textBlobBuilder;
|
| const char bunny[] = "/(^x^)\\";
|
| const int len = sizeof(bunny) - 1;
|
| uint16_t glyphs[len];
|
| SkPaint paint;
|
| paint.textToGlyphs(bunny, len, glyphs);
|
| paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
|
| int runs[] = { 3, 1, 3 };
|
| SkPoint textPos = { 20, 50 };
|
| int glyphIndex = 0;
|
| for (auto runLen : runs) {
|
| paint.setTextSize(1 == runLen ? 20 : 50);
|
| const SkTextBlobBuilder::RunBuffer& run =
|
| textBlobBuilder.allocRun(paint, runLen, textPos.fX, textPos.fY);
|
| memcpy(run.glyphs, &glyphs[glyphIndex], sizeof(glyphs[0]) * runLen);
|
| textPos.fX += paint.measureText(&glyphs[glyphIndex], sizeof(glyphs[0]) * runLen, nullptr);
|
| glyphIndex += runLen;
|
| }
|
| sk_sp<const SkTextBlob> blob = textBlobBuilder.make();
|
| paint.reset();
|
| canvas->drawTextBlob(blob.get(), 0, 0, paint);
|
| paint.setStyle(SkPaint::kStroke_Style);
|
| canvas->drawRect(blob->bounds(), paint); |
| ## |
| |
| #SeeAlso SkPath::getBounds |
| |
| #Method ## |
| |
| # ------------------------------------------------------------------------------ |
| |
| #Method uint32_t uniqueID() const |
| #In Property |
| #Line # returns identifier for Text_Blob ## |
| |
| Returns a non-zero value unique among all text blobs. |
| |
| #Return identifier for Text_Blob ## |
| |
| #Example |
| for (int index = 0; index < 2; ++index) {
|
| SkTextBlobBuilder textBlobBuilder;
|
| const char bunny[] = "/(^x^)\\";
|
| const int len = sizeof(bunny) - 1;
|
| uint16_t glyphs[len];
|
| SkPaint paint;
|
| paint.textToGlyphs(bunny, len, glyphs);
|
| paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
|
| paint.setTextScaleX(0.5);
|
| int runs[] = { 3, 1, 3 };
|
| SkPoint textPos = { 20, 50 };
|
| int glyphIndex = 0;
|
| for (auto runLen : runs) {
|
| paint.setTextSize(1 == runLen ? 20 : 50);
|
| const SkTextBlobBuilder::RunBuffer& run =
|
| textBlobBuilder.allocRun(paint, runLen, textPos.fX, textPos.fY);
|
| memcpy(run.glyphs, &glyphs[glyphIndex], sizeof(glyphs[0]) * runLen);
|
| textPos.fX += paint.measureText(&glyphs[glyphIndex], sizeof(glyphs[0]) * runLen, nullptr);
|
| glyphIndex += runLen;
|
| }
|
| sk_sp<const SkTextBlob> blob = textBlobBuilder.make();
|
| paint.reset();
|
| canvas->drawTextBlob(blob.get(), 0, 0, paint);
|
| std::string id = "unique ID:" + std::to_string(blob->uniqueID());
|
| canvas->drawString(id.c_str(), 30, blob->bounds().fBottom + 15, paint);
|
| canvas->translate(blob->bounds().fRight + 10, 0);
|
| } |
| ## |
| |
| #SeeAlso SkRefCnt |
| |
| #Method ## |
| |
| # ------------------------------------------------------------------------------ |
| |
| #Method static sk_sp<SkTextBlob> MakeFromText( |
| const void* text, size_t byteLength, const SkPaint& paint) |
| #In Constructor |
| #Line # constructs Text_Blob with one run ## |
| |
| Creates Text_Blob with a single run. text meaning depends on Paint_Text_Encoding; |
| by default, text is encoded as UTF-8. |
| |
| paint contains attributes used to define the run text: #paint_font_metrics#. |
| |
| #Param text character code points or Glyphs drawn ## |
| #Param byteLength byte length of text array ## |
| #Param paint text size, typeface, text scale, and so on, used to draw ## |
| |
| #Return Text_Blob constructed from one run ## |
| |
| #Example |
| #Height 24 |
| SkPaint blobPaint; |
| blobPaint.setColor(SK_ColorRED); // ignored |
| blobPaint.setTextSize(24); // respected |
| blobPaint.setAntiAlias(true); // ignored |
| SkPaint canvasPaint = blobPaint; |
| canvasPaint.setColor(SK_ColorBLUE); // respected |
| canvasPaint.setTextSize(2); // ignored |
| sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World", 11, blobPaint); |
| canvas->drawTextBlob(blob, 20, 20, canvasPaint); |
| ## |
| |
| #SeeAlso MakeFromString TextBlobBuilder |
| |
| ## |
| |
| # ------------------------------------------------------------------------------ |
| |
| #Method static sk_sp<SkTextBlob> MakeFromString(const char* string, const SkPaint& paint) |
| #In Constructor |
| #Line # constructs Text_Blob with one run ## |
| |
| Creates Text_Blob with a single run. string meaning depends on Paint_Text_Encoding; |
| by default, string is encoded as UTF-8. |
| |
| paint contains Paint_Font_Metrics used to define the run text: #paint_font_metrics#. |
| |
| #Param string character code points or Glyphs drawn ## |
| #Param paint text size, typeface, text scale, and so on, used to draw ## |
| |
| #Return Text_Blob constructed from one run ## |
| |
| #Example |
| #Height 24 |
| SkPaint blobPaint; |
| blobPaint.setColor(SK_ColorRED); // ignored |
| blobPaint.setTextSize(24); // respected |
| blobPaint.setAntiAlias(true); // ignored |
| SkPaint canvasPaint = blobPaint; |
| canvasPaint.setColor(SK_ColorBLUE); // respected |
| canvasPaint.setTextSize(2); // ignored |
| sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromString("Hello World", blobPaint); |
| canvas->drawTextBlob(blob, 20, 20, canvasPaint); |
| ## |
| |
| #SeeAlso MakeFromText TextBlobBuilder |
| |
| ## |
| |
| # ------------------------------------------------------------------------------ |
| |
| #Method size_t serialize(const SkSerialProcs& procs, void* memory, size_t memory_size) const |
| #In Utility |
| #Line # writes Text_Blob to memory ## |
| |
| Writes data to allow later reconstruction of Text_Blob. memory points to storage |
| to receive the encoded data, and memory_size describes the size of storage. |
| Returns bytes used if provided storage is large enough to hold all data; |
| otherwise, returns zero. |
| |
| procs.fTypefaceProc permits supplying a custom function to encode Typeface. |
| If procs.fTypefaceProc is nullptr, default encoding is used. procs.fTypefaceCtx |
| may be used to provide user context to procs.fTypefaceProc; procs.fTypefaceProc |
| is called with a pointer to Typeface and user context. |
| |
| #Param procs custom serial data encoders; may be nullptr ## |
| #Param memory storage for data ## |
| #Param size size of storage ## |
| |
| #Return bytes written, or zero if required storage is larger than memory_size ## |
| |
| #Example |
| #Height 64 |
| ###$ |
| $Function |
| #include "SkSerialProcs.h" |
| $$ |
| $$$# |
| SkPaint blobPaint;
|
| blobPaint.setTextSize(24);
|
| sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World", 11, blobPaint);
|
| char storage[2048];
|
| size_t used = blob->serialize(SkSerialProcs(), storage, sizeof(storage));
|
| sk_sp<SkTextBlob> copy = SkTextBlob::Deserialize(storage, used, SkDeserialProcs());
|
| canvas->drawTextBlob(copy, 20, 20, SkPaint());
|
| std::string usage = "size=" + std::to_string(sizeof(storage)) + " used=" + std::to_string(used);
|
| canvas->drawString(usage.c_str(), 20, 40, SkPaint()); |
| ## |
| |
| #SeeAlso Deserialize SkSerialProcs |
| |
| #Method ## |
| |
| # ------------------------------------------------------------------------------ |
| |
| #Method sk_sp<SkData> serialize(const SkSerialProcs& procs) const |
| #In Utility |
| #Line # writes Text_Blob to Data ## |
| Returns storage containing Data describing Text_Blob, using optional custom |
| encoders. |
| |
| procs.fTypefaceProc permits supplying a custom function to encode Typeface. |
| If procs.fTypefaceProc is nullptr, default encoding is used. procs.fTypefaceCtx |
| may be used to provide user context to procs.fTypefaceProc; procs.fTypefaceProc |
| is called with a pointer to Typeface and user context. |
| |
| #Param procs custom serial data encoders; may be nullptr ## |
| |
| #Return storage containing serialized Text_Blob ## |
| |
| #Example |
| #Height 24 |
| ###$ |
| $Function |
| #include "SkSerialProcs.h" |
| $$ |
| $$$# |
| SkPaint blobPaint;
|
| blobPaint.setTextSize(24);
|
| sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World", 11, blobPaint);
|
| sk_sp<SkData> data = blob->serialize(SkSerialProcs());
|
| sk_sp<SkTextBlob> copy = SkTextBlob::Deserialize(data->data(), data->size(), SkDeserialProcs());
|
| canvas->drawTextBlob(copy, 20, 20, SkPaint()); |
| ## |
| |
| #SeeAlso Deserialize SkData SkSerialProcs |
| |
| #Method ## |
| |
| # ------------------------------------------------------------------------------ |
| |
| #Method static sk_sp<SkTextBlob> Deserialize(const void* data, size_t size, const SkDeserialProcs& procs) |
| #In Constructor |
| #Line # constructs Text_Blob from memory ## |
| |
| Recreates Text_Blob that was serialized into data. Returns constructed Text_Blob |
| if successful; otherwise, returns nullptr. Fails if size is smaller than |
| required data length, or if data does not permit constructing valid Text_Blob. |
| |
| procs.fTypefaceProc permits supplying a custom function to decode Typeface. |
| If procs.fTypefaceProc is nullptr, default decoding is used. procs.fTypefaceCtx |
| may be used to provide user context to procs.fTypefaceProc; procs.fTypefaceProc |
| is called with a pointer to Typeface data, data byte length, and user context. |
| |
| #Param data pointer for serial data ## |
| #Param size size of data ## |
| #Param procs custom serial data decoders; may be nullptr ## |
| |
| #Return Text_Blob constructed from data in memory ## |
| |
| #Example |
| #Height 24 |
| #Description |
| Text "Hacker" replaces "World!", but does not update its metrics. |
| When drawn, "Hacker" uses the spacing computed for "World!". |
| ## |
| ###$ |
| $Function |
| #include "SkSerialProcs.h" |
| $$ |
| $$$# |
| SkPaint blobPaint;
|
| blobPaint.setTextSize(24);
|
| sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World!", 12, blobPaint);
|
| sk_sp<SkData> data = blob->serialize(SkSerialProcs());
|
| uint16_t glyphs[6];
|
| blobPaint.textToGlyphs("Hacker", 6, glyphs);
|
| memcpy((char*)data->writable_data() + 0x54, glyphs, sizeof(glyphs));
|
| sk_sp<SkTextBlob> copy = SkTextBlob::Deserialize(data->data(), data->size(), SkDeserialProcs());
|
| canvas->drawTextBlob(copy, 20, 20, SkPaint()); |
| ## |
| |
| #SeeAlso serialize SkDeserialProcs |
| |
| #Method ## |
| |
| #Class SkTextBlob ## |
| |
| #Topic Text_Blob ## |