gm/hairmodes.cpp

   1 /*
   2  * Copyright 2011 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 "SkCanvas.h"
  10 #include "SkColorPriv.h"
  11 #include "SkShader.h"
  12
  13 constexpr SkBlendMode gModes[] = {
  14     SkBlendMode::kClear,
  15     SkBlendMode::kSrc,
  16     SkBlendMode::kDst,
  17     SkBlendMode::kSrcOver,
  18     SkBlendMode::kDstOver,
  19     SkBlendMode::kSrcIn,
  20     SkBlendMode::kDstIn,
  21     SkBlendMode::kSrcOut,
  22     SkBlendMode::kDstOut,
  23     SkBlendMode::kSrcATop,
  24     SkBlendMode::kDstATop,
  25     SkBlendMode::kXor,
  26 };
  27
  28 const int gWidth = 64;
  29 const int gHeight = 64;
  30 const SkScalar W = SkIntToScalar(gWidth);
  31 const SkScalar H = SkIntToScalar(gHeight);
  32
  33 static SkScalar drawCell(SkCanvas* canvas, SkBlendMode mode, SkAlpha a0, SkAlpha a1) {
  34
  35     SkPaint paint;
  36     paint.setAntiAlias(true);
  37
  38     SkRect r = SkRect::MakeWH(W, H);
  39     r.inset(W/10, H/10);
  40
  41     paint.setColor(SK_ColorBLUE);
  42     paint.setAlpha(a0);
  43     canvas->drawOval(r, paint);
  44
  45     paint.setColor(SK_ColorRED);
  46     paint.setAlpha(a1);
  47     paint.setBlendMode(mode);
  48     for (int angle = 0; angle < 24; ++angle) {
  49         SkScalar x = SkScalarCos(SkIntToScalar(angle) * (SK_ScalarPI * 2) / 24) * gWidth;
  50         SkScalar y = SkScalarSin(SkIntToScalar(angle) * (SK_ScalarPI * 2) / 24) * gHeight;
  51         paint.setStrokeWidth(SK_Scalar1 * angle * 2 / 24);
  52         canvas->drawLine(W/2, H/2, W/2 + x, H/2 + y, paint);
  53     }
  54
  55     return H;
  56 }
  57
  58 static sk_sp<SkShader> make_bg_shader() {
  59     SkBitmap bm;
  60     bm.allocN32Pixels(2, 2);
  61     *bm.getAddr32(0, 0) = *bm.getAddr32(1, 1) = 0xFFFFFFFF;
  62     *bm.getAddr32(1, 0) = *bm.getAddr32(0, 1) = SkPackARGB32(0xFF, 0xCE, 0xCF, 0xCE);
  63
  64     SkMatrix m;
  65     m.setScale(SkIntToScalar(6), SkIntToScalar(6));
  66     return SkShader::MakeBitmapShader(bm,
  67                                       SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode, &m);
  68 }
  69
  70 namespace skiagm {
  71
  72     class HairModesGM : public GM {
  73         SkPaint fBGPaint;
  74
  75     protected:
  76         SkString onShortName() override {
  77             return SkString("hairmodes");
  78         }
  79
  80         virtual SkISize onISize() override { return SkISize::Make(640, 480); }
  81
  82         void onOnceBeforeDraw() override {
  83             fBGPaint.setShader(make_bg_shader());
  84         }
  85
  86         void onDraw(SkCanvas* canvas) override {
  87             const SkRect bounds = SkRect::MakeWH(W, H);
  88             constexpr SkAlpha gAlphaValue[] = { 0xFF, 0x88, 0x88 };
  89
  90             canvas->translate(SkIntToScalar(4), SkIntToScalar(4));
  91
  92             for (int alpha = 0; alpha < 4; ++alpha) {
  93                 canvas->save();
  94                 canvas->save();
  95                 for (size_t i = 0; i < SK_ARRAY_COUNT(gModes); ++i) {
  96                     if (6 == i) {
  97                         canvas->restore();
  98                         canvas->translate(W * 5, 0);
  99                         canvas->save();
 100                     }
 101
 102                     canvas->drawRect(bounds, fBGPaint);
 103                     canvas->saveLayer(&bounds, nullptr);
 104                     SkScalar dy = drawCell(canvas, gModes[i],
 105                                            gAlphaValue[alpha & 1],
 106                                            gAlphaValue[alpha & 2]);
 107                     canvas->restore();
 108
 109                     canvas->translate(0, dy * 5 / 4);
 110                 }
 111                 canvas->restore();
 112                 canvas->restore();
 113                 canvas->translate(W * 5 / 4, 0);
 114             }
 115         }
 116
 117     private:
 118         typedef GM INHERITED;
 119     };
 120
 121     //////////////////////////////////////////////////////////////////////////////
 122
 123     static GM* MyFactory(void*) { return new HairModesGM; }
 124     static GMRegistry reg(MyFactory);
 125
 126 }