gm/textblobshader.cpp

   1 /*
   2  * Copyright 2014 Google Inc.
   3  *
   4  * Use of this source code is governed by a BSD-style license that can be
   5  * found in the LICENSE file.
   6  */
   7
   8 #include "gm.h"
   9 #include "sk_tool_utils.h"
  10
  11 #include "SkCanvas.h"
  12 #include "SkGradientShader.h"
  13 #include "SkPoint.h"
  14 #include "SkShader.h"
  15 #include "SkTextBlob.h"
  16 #include "SkTDArray.h"
  17 #include "SkTypeface.h"
  18
  19 // This GM exercises drawTextBlob offset vs. shader space behavior.
  20 class TextBlobShaderGM : public skiagm::GM {
  21 public:
  22     TextBlobShaderGM(const char* txt) {
  23         SkPaint p;
  24         sk_tool_utils::set_portable_typeface(&p);
  25         size_t txtLen = strlen(txt);
  26         fGlyphs.append(p.textToGlyphs(txt, txtLen, nullptr));
  27         p.textToGlyphs(txt, txtLen, fGlyphs.begin());
  28     }
  29
  30 protected:
  31
  32     void onOnceBeforeDraw() override {
  33         SkPaint p;
  34         p.setAntiAlias(true);
  35         p.setSubpixelText(true);
  36         p.setTextSize(30);
  37         p.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
  38         sk_tool_utils::set_portable_typeface(&p);
  39
  40         SkTextBlobBuilder builder;
  41         int glyphCount = fGlyphs.count();
  42         const SkTextBlobBuilder::RunBuffer* run;
  43
  44         run = &builder.allocRun(p, glyphCount, 10, 10, nullptr);
  45         memcpy(run->glyphs, fGlyphs.begin(), glyphCount * sizeof(uint16_t));
  46
  47         run = &builder.allocRunPosH(p, glyphCount,  80, nullptr);
  48         memcpy(run->glyphs, fGlyphs.begin(), glyphCount * sizeof(uint16_t));
  49         for (int i = 0; i < glyphCount; ++i) {
  50             run->pos[i] = p.getTextSize() * i * .75f;
  51         }
  52
  53         run = &builder.allocRunPos(p, glyphCount, nullptr);
  54         memcpy(run->glyphs, fGlyphs.begin(), glyphCount * sizeof(uint16_t));
  55         for (int i = 0; i < glyphCount; ++i) {
  56             run->pos[i * 2] = p.getTextSize() * i * .75f;
  57             run->pos[i * 2 + 1] = 150 + 5 * sinf((float)i * 8 / glyphCount);
  58         }
  59
  60         fBlob = builder.make();
  61
  62         SkColor  colors[2];
  63         colors[0] = SK_ColorRED;
  64         colors[1] = SK_ColorGREEN;
  65
  66         SkScalar pos[SK_ARRAY_COUNT(colors)];
  67         for (unsigned i = 0; i < SK_ARRAY_COUNT(pos); ++i) {
  68             pos[i] = (float)i / (SK_ARRAY_COUNT(pos) - 1);
  69         }
  70
  71         SkISize sz = this->onISize();
  72         fShader = SkGradientShader::MakeRadial(SkPoint::Make(SkIntToScalar(sz.width() / 2),
  73                                                SkIntToScalar(sz.height() / 2)),
  74                                                sz.width() * .66f, colors, pos,
  75                                                SK_ARRAY_COUNT(colors),
  76                                                SkShader::kRepeat_TileMode);
  77     }
  78
  79     SkString onShortName() override {
  80         return SkString("textblobshader");
  81     }
  82
  83     SkISize onISize() override {
  84         return SkISize::Make(640, 480);
  85     }
  86
  87     void onDraw(SkCanvas* canvas) override {
  88         SkPaint p;
  89         p.setStyle(SkPaint::kFill_Style);
  90         p.setShader(fShader);
  91
  92         SkISize sz = this->onISize();
  93         constexpr int kXCount = 4;
  94         constexpr int kYCount = 3;
  95         for (int i = 0; i < kXCount; ++i) {
  96             for (int j = 0; j < kYCount; ++j) {
  97                 canvas->drawTextBlob(fBlob,
  98                                      SkIntToScalar(i * sz.width() / kXCount),
  99                                      SkIntToScalar(j * sz.height() / kYCount),
 100                                      p);
 101             }
 102         }
 103     }
 104
 105 private:
 106     SkTDArray<uint16_t> fGlyphs;
 107     sk_sp<SkTextBlob>   fBlob;
 108     sk_sp<SkShader>     fShader;
 109
 110     typedef skiagm::GM INHERITED;
 111 };
 112
 113 DEF_GM(return new TextBlobShaderGM("Blobber");)