#Topic Text_Blob_Builder #Alias Text_Blob_Builder_Reference ## #Class SkTextBlobBuilder Helper class for constructing SkTextBlob. #Subtopic Overview #Populate ## #Subtopic Class #Populate ## #Subtopic Constructor #Populate ## #Subtopic Member_Function #Populate ## # ------------------------------------------------------------------------------ #Struct RunBuffer #Line # storage for Glyphs and Glyph positions ## #Code struct RunBuffer { SkGlyphID* glyphs; SkScalar* pos; char* utf8text; uint32_t* clusters; }; ## RunBuffer supplies storage for Glyphs and positions within a run. A run is a sequence of Glyphs sharing Paint_Font_Metrics and positioning. Each run may position its Glyphs in one of three ways: by specifying where the first Glyph is drawn, and allowing Paint_Font_Metrics to determine the advance to subsequent Glyphs; by specifying a baseline, and the position on that baseline for each Glyph in run; or by providing Point array, one per Glyph. #Subtopic Member #Populate ## #Member SkGlyphID* glyphs #Line # storage for Glyphs in run ## glyphs points to memory for one or more Glyphs. glyphs memory must be written to by the caller. ## #Member SkScalar* pos #Line # storage for positions in run ## pos points to memory for Glyph positions. Depending on how RunBuffer is allocated, pos may point to zero bytes per Glyph, one Scalar per Glyph, or one Point per Glyph. ## #Member char* utf8text #Line # reserved for future use ## Reserved for future use. utf8text should not be read or written. ## #Member uint32_t* clusters #Line # reserved for future use ## Reserved for future use. clusters should not be read or written. ## #SeeAlso allocRun allocRunPos allocRunPosH #Struct RunBuffer ## # ------------------------------------------------------------------------------ #Method SkTextBlobBuilder() #In Constructor #Line # constructs with default values ## Constructs empty Text_Blob_Builder. By default, Text_Blob_Builder has no runs. #Return empty Text_Blob_Builder ## #Example SkTextBlobBuilder builder; sk_sp blob = builder.make(); SkDebugf("blob " "%s" " nullptr", blob == nullptr ? "equals" : "does not equal"); #StdOut blob equals nullptr ## ## #SeeAlso make SkTextBlob::MakeFromText #Method ## # ------------------------------------------------------------------------------ #Method ~SkTextBlobBuilder() #In Constructor #Line # deletes storage ## Deletes data allocated internally by Text_Blob_Builder. #NoExample ## #SeeAlso SkTextBlobBuilder() #Method ## # ------------------------------------------------------------------------------ #Method sk_sp make() #In Constructor #Line # constructs Text_Blob from bulider ## Returns Text_Blob built from runs of Glyphs added by builder. Returned Text_Blob is immutable; it may be copied, but its contents may not be altered. Returns nullptr if no runs of Glyphs were added by builder. Resets Text_Blob_Builder to its initial empty state, allowing it to be reused to build a new set of runs. #Return Text_Blob or nullptr ## #Example SkTextBlobBuilder builder; sk_sp blob = builder.make(); SkDebugf("blob " "%s" " nullptr\n", blob == nullptr ? "equals" : "does not equal"); SkPaint paint; paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding); paint.textToGlyphs("x", 1, builder.allocRun(paint, 1, 20, 20).glyphs); blob = builder.make(); SkDebugf("blob " "%s" " nullptr\n", blob == nullptr ? "equals" : "does not equal"); blob = builder.make(); SkDebugf("blob " "%s" " nullptr\n", blob == nullptr ? "equals" : "does not equal"); #StdOut blob equals nullptr blob does not equal nullptr blob equals nullptr ## ## #SeeAlso SkTextBlob::MakeFromText #Method ## # ------------------------------------------------------------------------------ #Method const RunBuffer& allocRun(const SkPaint& font, int count, SkScalar x, SkScalar y, const SkRect* bounds = nullptr) #In Allocator #Line # returns writable glyph buffer at Point ## Returns run with storage for Glyphs. Caller must write count Glyphs to RunBuffer.glyphs before next call to FontBlobBuilder. RunBuffer.utf8text, and RunBuffer.clusters should be ignored. Glyphs share Paint_Font_Metrics in font, including: #paint_font_metrics#. Glyphs are positioned on a baseline at (x, y), using font Paint_Font_Metrics to determine their relative placement. bounds defines an optional bounding box, used to suppress drawing when Text_Blob bounds does not intersect Surface bounds. If bounds is nullptr, Text_Blob bounds is computed from (x, y) and RunBuffer.glyphs Paint_Font_Metrics. #Param font Paint used for this run ## #Param count number of glyphs ## #Param x horizontal offset within the blob ## #Param y vertical offset within the blob ## #Param bounds optional run bounding box ## #Return writable glyph buffer ## #Example #Height 60 SkTextBlobBuilder builder; SkPaint paint, glyphPaint; glyphPaint.setTextEncoding(SkPaint::kGlyphID_TextEncoding); const SkTextBlobBuilder::RunBuffer& run = builder.allocRun(glyphPaint, 5, 20, 20); paint.textToGlyphs("hello", 5, run.glyphs); canvas->drawRect({20, 20, 30, 30}, paint); canvas->drawTextBlob(builder.make(), 20, 20, paint); ## #SeeAlso allocRunPosH allocRunPos #Method ## # ------------------------------------------------------------------------------ #Method const RunBuffer& allocRunPosH(const SkPaint& font, int count, SkScalar y, const SkRect* bounds = nullptr) #In Allocator #Line # returns writable glyph and x-axis position buffers ## Returns run with storage for Glyphs and positions along baseline. Caller must write count Glyphs to RunBuffer.glyphs, and count Scalars to RunBuffer.pos; before next call to FontBlobBuilder. RunBuffer.utf8text, and RunBuffer.clusters should be ignored. Glyphs share Paint_Font_Metrics in font, including: #paint_font_metrics#. Glyphs are positioned on a baseline at y, using x-axis positions written by caller to RunBuffer.pos. bounds defines an optional bounding box, used to suppress drawing when Text_Blob bounds does not intersect Surface bounds. If bounds is nullptr, Text_Blob bounds is computed from y, RunBuffer.pos, and RunBuffer.glyphs Paint_Font_Metrics. #Param font Paint used for this run ## #Param count number of Glyphs ## #Param y vertical offset within the blob ## #Param bounds optional run bounding box ## #Return writable glyph buffer and x-axis position buffer ## #Example #Height 60 SkTextBlobBuilder builder; SkPaint paint, glyphPaint; glyphPaint.setTextEncoding(SkPaint::kGlyphID_TextEncoding); const SkTextBlobBuilder::RunBuffer& run = builder.allocRunPosH(glyphPaint, 5, 20); paint.textToGlyphs("hello", 5, run.glyphs); SkScalar positions[] = {0, 10, 20, 40, 80}; memcpy(run.pos, positions, sizeof(positions)); canvas->drawTextBlob(builder.make(), 20, 20, paint); ## #SeeAlso allocRunPos allocRun #Method ## # ------------------------------------------------------------------------------ #Method const RunBuffer& allocRunPos(const SkPaint& font, int count, const SkRect* bounds = nullptr) #In Allocator #Line # returns writable glyph and Point buffers ## Returns run with storage for Glyphs and Point positions. Caller must write count Glyphs to RunBuffer.glyphs, and count Points to RunBuffer.pos; before next call to FontBlobBuilder. RunBuffer.utf8text, and RunBuffer.clusters should be ignored. Glyphs share Paint_Font_Metrics in font, including: #paint_font_metrics#. Glyphs are positioned using Points written by caller to RunBuffer.pos, using two Scalar values for each Point. bounds defines an optional bounding box, used to suppress drawing when Text_Blob bounds does not intersect Surface bounds. If bounds is nullptr, Text_Blob bounds is computed from RunBuffer.pos, and RunBuffer.glyphs Paint_Font_Metrics. #Param font Paint used for this run ## #Param count number of Glyphs ## #Param bounds optional run bounding box ## #Return writable glyph buffer and Point buffer ## #Example #Height 90 SkTextBlobBuilder builder; SkPaint paint, glyphPaint; glyphPaint.setTextEncoding(SkPaint::kGlyphID_TextEncoding); const SkTextBlobBuilder::RunBuffer& run = builder.allocRunPos(glyphPaint, 5); paint.textToGlyphs("hello", 5, run.glyphs); SkPoint positions[] = {{0, 0}, {10, 10}, {20, 20}, {40, 40}, {80, 80}}; memcpy(run.pos, positions, sizeof(positions)); canvas->drawTextBlob(builder.make(), 20, 20, paint); ## #SeeAlso allocRunPosH allocRun #Method ## #Class SkTextBlobBuilder ## #Topic Text_Blob_Builder ##