#Topic Text_Blob
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#Alias Text_Blob_Reference ##
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#Class SkTextBlob
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#Code
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#Populate
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##
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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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#Populate
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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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SkFont font;
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font.textToGlyphs(bunny, len, SkTextEncoding::kUTF8, glyphs, sizeof(glyphs));
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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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font.setSize(1 == runLen ? 20 : 50);
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const SkTextBlobBuilder::RunBuffer& run =
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textBlobBuilder.allocRun(font, runLen, textPos.fX, textPos.fY);
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memcpy(run.glyphs, &glyphs[glyphIndex], sizeof(glyphs[0]) * runLen);
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textPos.fX += font.measureText(&glyphs[glyphIndex], sizeof(glyphs[0]) * runLen,
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SkTextEncoding::kGlyphID);
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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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SkPaint paint;
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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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#Populate
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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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SkFont font;
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font.textToGlyphs(bunny, len, SkTextEncoding::kUTF8, glyphs, sizeof(glyphs));
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font.setScaleX(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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font.setSize(1 == runLen ? 20 : 50);
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const SkTextBlobBuilder::RunBuffer& run =
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textBlobBuilder.allocRun(font, runLen, textPos.fX, textPos.fY);
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memcpy(run.glyphs, &glyphs[glyphIndex], sizeof(glyphs[0]) * runLen);
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textPos.fX += font.measureText(&glyphs[glyphIndex], sizeof(glyphs[0]) * runLen,
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SkTextEncoding::kGlyphID);
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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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SkPaint paint;
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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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#Subtopic Text_Intercepts
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#Line # advanced underline, strike through ##
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Text_Intercepts describe the intersection of drawn text Glyphs with a pair
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of lines parallel to the text advance. Text_Intercepts permits creating a
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underline that skips Descenders.
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#Method int getIntercepts(const SkScalar bounds[2], SkScalar intervals[],
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const SkPaint* paint = nullptr) const;
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#In Text_Intercepts
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#Line # returns where lines intersect Text_Blob; underlines ##
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#Populate
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#Example
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#Height 143
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void draw(SkCanvas* canvas) {
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SkFont font;
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font.setSize(120);
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SkPoint textPos = { 20, 110 };
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int len = 3;
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SkTextBlobBuilder textBlobBuilder;
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const SkTextBlobBuilder::RunBuffer& run =
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textBlobBuilder.allocRun(font, len, textPos.fX, textPos.fY);
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run.glyphs[0] = 10;
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run.glyphs[1] = 20;
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run.glyphs[2] = 30;
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sk_sp<const SkTextBlob> blob = textBlobBuilder.make();
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SkPaint paint;
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SkScalar bounds[] = { 116, 134 };
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int count = blob->getIntercepts(bounds, nullptr);
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std::vector<SkScalar> intervals;
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intervals.resize(count);
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(void) paint.getTextBlobIntercepts(blob.get(), bounds, &intervals.front());
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canvas->drawTextBlob(blob.get(), 0, 0, paint);
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paint.setColor(0xFFFF7777);
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SkScalar x = textPos.fX;
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for (int i = 0; i < count; i+= 2) {
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canvas->drawRect({x, bounds[0], intervals[i], bounds[1]}, paint);
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x = intervals[i + 1];
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}
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canvas->drawRect({intervals[count - 1], bounds[0], 180, bounds[1]}, paint);
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}
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##
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#Method ##
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#Subtopic Text_Intercepts ##
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# ------------------------------------------------------------------------------
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#Method static sk_sp<SkTextBlob> MakeFromText(const void* text, size_t byteLength, const SkFont& font,
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SkTextEncoding encoding = kUTF8_SkTextEncoding)
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#In Constructors
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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 Text_Encoding;
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by default, text is encoded as UTF-8.
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font contains attributes used to define the run text: #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 font text size, typeface, text scale, and so on, used to draw ##
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#Param encoding one of: kUTF8_SkTextEncoding, kUTF16_SkTextEncoding,
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kUTF32_SkTextEncoding, kGlyphID_SkTextEncoding
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##
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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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SkFont font;
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font.setSize(24);
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SkPaint canvasPaint;
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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, font);
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canvas->drawTextBlob(blob, 20, 20, canvasPaint);
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##
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#SeeAlso MakeFromString SkTextBlobBuilder
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##
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# ------------------------------------------------------------------------------
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#Method static sk_sp<SkTextBlob> MakeFromString(const char* string, const SkFont& font,
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SkTextEncoding encoding = kUTF8_SkTextEncoding)
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#In Constructors
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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 Text_Encoding;
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by default, string is encoded as UTF-8.
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font contains Font_Metrics used to define the run text: #font_metrics#.
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#Param string character code points or Glyphs drawn ##
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#Param font text size, typeface, text scale, and so on, used to draw ##
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#Param encoding one of: kUTF8_SkTextEncoding, kUTF16_SkTextEncoding,
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kUTF32_SkTextEncoding, kGlyphID_SkTextEncoding
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##
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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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SkFont font;
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font.setSize(24);
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SkPaint canvasPaint;
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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", font);
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canvas->drawTextBlob(blob, 20, 20, canvasPaint);
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##
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#SeeAlso MakeFromText SkTextBlobBuilder
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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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#Populate
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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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SkFont blobFont;
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blobFont.setSize(24);
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sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World", 11, blobFont);
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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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#Populate
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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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SkFont blobFont;
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blobFont.setSize(24);
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sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World", 11, blobFont);
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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 Constructors
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#Line # constructs Text_Blob from memory ##
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#Populate
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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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SkFont blobFont;
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blobFont.setSize(24);
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sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World!", 12, blobFont);
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sk_sp<SkData> data = blob->serialize(SkSerialProcs());
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uint16_t glyphs[6];
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SkPaint blobPaint;
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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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