src/third_party/skia/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
  10 #include "SkCanvas.h"
  11 #include "SkGradientShader.h"
  12 #include "SkPoint.h"
  13 #include "SkShader.h"
  14 #include "SkTextBlob.h"
  15 #include "SkTDArray.h"
  16 #include "SkTypeface.h"
  17
  18 // This GM exercises drawTextBlob offset vs. shader space behavior.
  19 class TextBlobShaderGM : public skiagm::GM {
  20 public:
  21     TextBlobShaderGM(const char* txt) {
  22         SkPaint p;
  23         size_t txtLen = strlen(txt);
  24         fGlyphs.append(p.textToGlyphs(txt, txtLen, NULL));
  25         p.textToGlyphs(txt, txtLen, fGlyphs.begin());
  26     }
  27
  28 protected:
  29
  30     virtual void onOnceBeforeDraw() SK_OVERRIDE {
  31         SkPaint p;
  32         p.setAntiAlias(true);
  33         p.setSubpixelText(true);
  34         p.setTextSize(30);
  35         p.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
  36
  37         SkTextBlobBuilder builder;
  38         int glyphCount = fGlyphs.count();
  39         const SkTextBlobBuilder::RunBuffer* run;
  40
  41         run = &builder.allocRun(p, glyphCount, 10, 10, NULL);
  42         memcpy(run->glyphs, fGlyphs.begin(), glyphCount * sizeof(uint16_t));
  43
  44         run = &builder.allocRunPosH(p, glyphCount,  80, NULL);
  45         memcpy(run->glyphs, fGlyphs.begin(), glyphCount * sizeof(uint16_t));
  46         for (int i = 0; i < glyphCount; ++i) {
  47             run->pos[i] = p.getTextSize() * i * .75f;
  48         }
  49
  50         run = &builder.allocRunPos(p, glyphCount, NULL);
  51         memcpy(run->glyphs, fGlyphs.begin(), glyphCount * sizeof(uint16_t));
  52         for (int i = 0; i < glyphCount; ++i) {
  53             run->pos[i * 2] = p.getTextSize() * i * .75f;
  54             run->pos[i * 2 + 1] = 150 + 5 * sinf((float)i * 8 / glyphCount);
  55         }
  56
  57         fBlob.reset(builder.build());
  58
  59         SkColor  colors[2];
  60         colors[0] = SK_ColorRED;
  61         colors[1] = SK_ColorGREEN;
  62
  63         SkScalar pos[SK_ARRAY_COUNT(colors)];
  64         for (unsigned i = 0; i < SK_ARRAY_COUNT(pos); ++i) {
  65             pos[i] = (float)i / (SK_ARRAY_COUNT(pos) - 1);
  66         }
  67
  68         SkISize sz = this->onISize();
  69         fShader.reset(SkGradientShader::CreateRadial(SkPoint::Make(SkIntToScalar(sz.width() / 2),
  70                                                                    SkIntToScalar(sz.height() / 2)),
  71                                                      sz.width() * .66f, colors, pos,
  72                                                      SK_ARRAY_COUNT(colors),
  73                                                      SkShader::kRepeat_TileMode));
  74     }
  75
  76     virtual uint32_t onGetFlags() const SK_OVERRIDE {
  77         return kSkip565_Flag;
  78     }
  79
  80     virtual SkString onShortName() SK_OVERRIDE {
  81         return SkString("textblobshader");
  82     }
  83
  84     virtual SkISize onISize() SK_OVERRIDE {
  85         return SkISize::Make(640, 480);
  86     }
  87
  88     virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
  89         SkPaint p;
  90         p.setStyle(SkPaint::kFill_Style);
  91         p.setShader(fShader);
  92
  93         SkISize sz = this->onISize();
  94         static const int kXCount = 4;
  95         static const int kYCount = 3;
  96         for (int i = 0; i < kXCount; ++i) {
  97             for (int j = 0; j < kYCount; ++j) {
  98                 canvas->drawTextBlob(fBlob,
  99                                      SkIntToScalar(i * sz.width() / kXCount),
 100                                      SkIntToScalar(j * sz.height() / kYCount),
 101                                      p);
 102             }
 103         }
 104     }
 105
 106 private:
 107     SkTDArray<uint16_t>            fGlyphs;
 108     SkAutoTUnref<const SkTextBlob> fBlob;
 109     SkAutoTUnref<SkShader>         fShader;
 110
 111     typedef skiagm::GM INHERITED;
 112 };
 113
 114 DEF_GM( return SkNEW_ARGS(TextBlobShaderGM, ("Blobber")); )