57ca297f0c
missed several SkTextBlob::MakeAsDrawText that needed to become SkTextBlob::MakeFromText. NOTRY=true TBR=caryclark@google.com Docs-Preview: https://skia.org/?cl=146861 Bug: skia:6818 Change-Id: Ief383113823ca7bcd33fa83216e8c452b6a186fe Reviewed-on: https://skia-review.googlesource.com/146861 Commit-Queue: Cary Clark <caryclark@skia.org> Auto-Submit: Cary Clark <caryclark@skia.org> Reviewed-by: Cary Clark <caryclark@skia.org>
326 lines
11 KiB
Plaintext
326 lines
11 KiB
Plaintext
#Topic Text_Blob
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#Alias Text_Blob_Reference ##
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#PhraseDef paint_font_metrics
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Typeface, Paint_Text_Size, Paint_Text_Scale_X,
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Paint_Text_Skew_X, Paint_Text_Align, Paint_Hinting, Anti_Alias, Paint_Fake_Bold,
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Font_Embedded_Bitmaps, Full_Hinting_Spacing, LCD_Text, Linear_Text,
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and Subpixel_Text
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##
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Text_Blob holds one or more runs of text. Each run associates a string of Glyphs
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with a position and Paint. Each Paint contains attributes used
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to define the run text: #paint_font_metrics#.
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Text_Blob runs of text use Glyph_ID encoding; each run Paint must set
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Paint_Text_Encoding to SkPaint::kGlyphID_TextEncoding.
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Text_Blob is constructed with SkTextBlob::MakeFromText or Text_Blob_Builder.
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Once created, Text_Blob can not be modified.
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#Subtopic Overview
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#Populate
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##
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#Subtopic Constructor
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#Populate
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##
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#Subtopic Member_Function
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#Populate
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##
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# ------------------------------------------------------------------------------
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#Class SkTextBlob
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SkTextBlob combines multiple text runs into an immutable container. Each text
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run consists of Glyphs, Paint, and position. Only parts of Paint related to
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fonts and text rendering are used by run.
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# ------------------------------------------------------------------------------
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#Method const SkRect& bounds() const
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#In Property
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#Line # returns conservative bounding box ##
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Returns conservative bounding box. Uses Paint associated with each glyph to
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determine glyph bounds, and unions all bounds. Returned bounds may be
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larger than the bounds of all Glyphs in runs.
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#Return conservative bounding box ##
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#Example
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#Height 70
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SkTextBlobBuilder textBlobBuilder;
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const char bunny[] = "/(^x^)\\";
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const int len = sizeof(bunny) - 1;
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uint16_t glyphs[len];
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SkPaint paint;
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paint.textToGlyphs(bunny, len, glyphs);
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paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
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int runs[] = { 3, 1, 3 };
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SkPoint textPos = { 20, 50 };
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int glyphIndex = 0;
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for (auto runLen : runs) {
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paint.setTextSize(1 == runLen ? 20 : 50);
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const SkTextBlobBuilder::RunBuffer& run =
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textBlobBuilder.allocRun(paint, runLen, textPos.fX, textPos.fY);
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memcpy(run.glyphs, &glyphs[glyphIndex], sizeof(glyphs[0]) * runLen);
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textPos.fX += paint.measureText(&glyphs[glyphIndex], sizeof(glyphs[0]) * runLen, nullptr);
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glyphIndex += runLen;
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}
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sk_sp<const SkTextBlob> blob = textBlobBuilder.make();
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paint.reset();
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canvas->drawTextBlob(blob.get(), 0, 0, paint);
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paint.setStyle(SkPaint::kStroke_Style);
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canvas->drawRect(blob->bounds(), paint);
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##
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#SeeAlso SkPath::getBounds
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#Method ##
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# ------------------------------------------------------------------------------
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#Method uint32_t uniqueID() const
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#In Property
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#Line # returns identifier for Text_Blob ##
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Returns a non-zero value unique among all text blobs.
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#Return identifier for Text_Blob ##
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#Example
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for (int index = 0; index < 2; ++index) {
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SkTextBlobBuilder textBlobBuilder;
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const char bunny[] = "/(^x^)\\";
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const int len = sizeof(bunny) - 1;
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uint16_t glyphs[len];
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SkPaint paint;
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paint.textToGlyphs(bunny, len, glyphs);
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paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
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paint.setTextScaleX(0.5);
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int runs[] = { 3, 1, 3 };
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SkPoint textPos = { 20, 50 };
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int glyphIndex = 0;
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for (auto runLen : runs) {
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paint.setTextSize(1 == runLen ? 20 : 50);
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const SkTextBlobBuilder::RunBuffer& run =
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textBlobBuilder.allocRun(paint, runLen, textPos.fX, textPos.fY);
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memcpy(run.glyphs, &glyphs[glyphIndex], sizeof(glyphs[0]) * runLen);
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textPos.fX += paint.measureText(&glyphs[glyphIndex], sizeof(glyphs[0]) * runLen, nullptr);
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glyphIndex += runLen;
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}
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sk_sp<const SkTextBlob> blob = textBlobBuilder.make();
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paint.reset();
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canvas->drawTextBlob(blob.get(), 0, 0, paint);
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std::string id = "unique ID:" + std::to_string(blob->uniqueID());
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canvas->drawString(id.c_str(), 30, blob->bounds().fBottom + 15, paint);
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canvas->translate(blob->bounds().fRight + 10, 0);
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}
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##
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#SeeAlso SkRefCnt
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#Method ##
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# ------------------------------------------------------------------------------
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#Method static sk_sp<SkTextBlob> MakeFromText(
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const void* text, size_t byteLength, const SkPaint& paint)
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#In Constructor
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#Line # constructs Text_Blob with one run ##
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Creates Text_Blob with a single run. text meaning depends on Paint_Text_Encoding;
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by default, text is encoded as UTF-8.
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paint contains attributes used to define the run text: #paint_font_metrics#.
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#Param text character code points or Glyphs drawn ##
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#Param byteLength byte length of text array ##
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#Param paint text size, typeface, text scale, and so on, used to draw ##
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#Return Text_Blob constructed from one run ##
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#Example
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#Height 24
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SkPaint blobPaint;
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blobPaint.setColor(SK_ColorRED); // ignored
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blobPaint.setTextSize(24); // respected
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blobPaint.setAntiAlias(true); // ignored
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SkPaint canvasPaint = blobPaint;
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canvasPaint.setColor(SK_ColorBLUE); // respected
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canvasPaint.setTextSize(2); // ignored
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sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World", 11, blobPaint);
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canvas->drawTextBlob(blob, 20, 20, canvasPaint);
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##
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#SeeAlso MakeFromString TextBlobBuilder
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##
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# ------------------------------------------------------------------------------
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#Method static sk_sp<SkTextBlob> MakeFromString(const char* string, const SkPaint& paint)
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#In Constructor
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#Line # constructs Text_Blob with one run ##
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Creates Text_Blob with a single run. string meaning depends on Paint_Text_Encoding;
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by default, string is encoded as UTF-8.
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paint contains Paint_Font_Metrics used to define the run text: #paint_font_metrics#.
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#Param string character code points or Glyphs drawn ##
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#Param paint text size, typeface, text scale, and so on, used to draw ##
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#Return Text_Blob constructed from one run ##
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#Example
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#Height 24
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SkPaint blobPaint;
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blobPaint.setColor(SK_ColorRED); // ignored
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blobPaint.setTextSize(24); // respected
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blobPaint.setAntiAlias(true); // ignored
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SkPaint canvasPaint = blobPaint;
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canvasPaint.setColor(SK_ColorBLUE); // respected
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canvasPaint.setTextSize(2); // ignored
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sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromString("Hello World", blobPaint);
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canvas->drawTextBlob(blob, 20, 20, canvasPaint);
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##
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#SeeAlso MakeFromText TextBlobBuilder
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##
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# ------------------------------------------------------------------------------
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#Method size_t serialize(const SkSerialProcs& procs, void* memory, size_t memory_size) const
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#In Utility
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#Line # writes Text_Blob to memory ##
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Writes data to allow later reconstruction of Text_Blob. memory points to storage
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to receive the encoded data, and memory_size describes the size of storage.
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Returns bytes used if provided storage is large enough to hold all data;
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otherwise, returns zero.
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procs.fTypefaceProc permits supplying a custom function to encode Typeface.
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If procs.fTypefaceProc is nullptr, default encoding is used. procs.fTypefaceCtx
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may be used to provide user context to procs.fTypefaceProc; procs.fTypefaceProc
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is called with a pointer to Typeface and user context.
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#Param procs custom serial data encoders; may be nullptr ##
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#Param memory storage for data ##
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#Param size size of storage ##
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#Return bytes written, or zero if required storage is larger than memory_size ##
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#Example
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#Height 64
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###$
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$Function
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#include "SkSerialProcs.h"
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$$
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$$$#
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SkPaint blobPaint;
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blobPaint.setTextSize(24);
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sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World", 11, blobPaint);
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char storage[2048];
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size_t used = blob->serialize(SkSerialProcs(), storage, sizeof(storage));
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sk_sp<SkTextBlob> copy = SkTextBlob::Deserialize(storage, used, SkDeserialProcs());
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canvas->drawTextBlob(copy, 20, 20, SkPaint());
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std::string usage = "size=" + std::to_string(sizeof(storage)) + " used=" + std::to_string(used);
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canvas->drawString(usage.c_str(), 20, 40, SkPaint());
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##
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#SeeAlso Deserialize SkSerialProcs
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#Method ##
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# ------------------------------------------------------------------------------
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#Method sk_sp<SkData> serialize(const SkSerialProcs& procs) const
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#In Utility
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#Line # writes Text_Blob to Data ##
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Returns storage containing Data describing Text_Blob, using optional custom
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encoders.
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procs.fTypefaceProc permits supplying a custom function to encode Typeface.
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If procs.fTypefaceProc is nullptr, default encoding is used. procs.fTypefaceCtx
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may be used to provide user context to procs.fTypefaceProc; procs.fTypefaceProc
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is called with a pointer to Typeface and user context.
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#Param procs custom serial data encoders; may be nullptr ##
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#Return storage containing serialized Text_Blob ##
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#Example
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#Height 24
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###$
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$Function
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#include "SkSerialProcs.h"
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$$
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$$$#
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SkPaint blobPaint;
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blobPaint.setTextSize(24);
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sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World", 11, blobPaint);
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sk_sp<SkData> data = blob->serialize(SkSerialProcs());
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sk_sp<SkTextBlob> copy = SkTextBlob::Deserialize(data->data(), data->size(), SkDeserialProcs());
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canvas->drawTextBlob(copy, 20, 20, SkPaint());
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##
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#SeeAlso Deserialize SkData SkSerialProcs
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#Method ##
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# ------------------------------------------------------------------------------
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#Method static sk_sp<SkTextBlob> Deserialize(const void* data, size_t size, const SkDeserialProcs& procs)
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#In Constructor
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#Line # constructs Text_Blob from memory ##
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Recreates Text_Blob that was serialized into data. Returns constructed Text_Blob
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if successful; otherwise, returns nullptr. Fails if size is smaller than
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required data length, or if data does not permit constructing valid Text_Blob.
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procs.fTypefaceProc permits supplying a custom function to decode Typeface.
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If procs.fTypefaceProc is nullptr, default decoding is used. procs.fTypefaceCtx
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may be used to provide user context to procs.fTypefaceProc; procs.fTypefaceProc
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is called with a pointer to Typeface data, data byte length, and user context.
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#Param data pointer for serial data ##
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#Param size size of data ##
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#Param procs custom serial data decoders; may be nullptr ##
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#Return Text_Blob constructed from data in memory ##
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#Example
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#Height 24
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#Description
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Text "Hacker" replaces "World!", but does not update its metrics.
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When drawn, "Hacker" uses the spacing computed for "World!".
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##
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###$
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$Function
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#include "SkSerialProcs.h"
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$$
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$$$#
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SkPaint blobPaint;
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blobPaint.setTextSize(24);
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sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World!", 12, blobPaint);
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sk_sp<SkData> data = blob->serialize(SkSerialProcs());
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uint16_t glyphs[6];
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blobPaint.textToGlyphs("Hacker", 6, glyphs);
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memcpy((char*)data->writable_data() + 0x54, glyphs, sizeof(glyphs));
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sk_sp<SkTextBlob> copy = SkTextBlob::Deserialize(data->data(), data->size(), SkDeserialProcs());
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canvas->drawTextBlob(copy, 20, 20, SkPaint());
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##
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#SeeAlso serialize SkDeserialProcs
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#Method ##
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#Class SkTextBlob ##
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#Topic Text_Blob ##
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