samplecode/SampleHairModes.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 "SampleCode.h"
   9 #include "SkView.h"
  10 #include "SkCanvas.h"
  11 #include "SkColorPriv.h"
  12 #include "SkShader.h"
  13
  14 static const SkBlendMode gModes[] = {
  15     SkBlendMode::kClear,
  16     SkBlendMode::kSrc,
  17     SkBlendMode::kDst,
  18     SkBlendMode::kSrcOver,
  19     SkBlendMode::kDstOver,
  20     SkBlendMode::kSrcIn,
  21     SkBlendMode::kDstIn,
  22     SkBlendMode::kSrcOut,
  23     SkBlendMode::kDstOut,
  24     SkBlendMode::kSrcATop,
  25     SkBlendMode::kDstATop,
  26     SkBlendMode::kXor,
  27 };
  28
  29 const int gWidth = 64;
  30 const int gHeight = 64;
  31 const SkScalar W = SkIntToScalar(gWidth);
  32 const SkScalar H = SkIntToScalar(gHeight);
  33
  34 static SkScalar drawCell(SkCanvas* canvas, SkBlendMode mode, SkAlpha a0, SkAlpha a1) {
  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, 0xCC, 0xCC, 0xCC);
  63
  64     SkMatrix m;
  65     m.setScale(SkIntToScalar(6), SkIntToScalar(6));
  66
  67     return SkShader::MakeBitmapShader(bm, SkShader::kRepeat_TileMode,
  68                                       SkShader::kRepeat_TileMode, &m);
  69 }
  70
  71 class HairModesView : public SampleView {
  72     SkPaint fBGPaint;
  73 public:
  74     HairModesView() {
  75         fBGPaint.setShader(make_bg_shader());
  76     }
  77
  78 protected:
  79     // overrides from SkEventSink
  80     virtual bool onQuery(SkEvent* evt) {
  81         if (SampleCode::TitleQ(*evt)) {
  82             SampleCode::TitleR(evt, "HairlineModes");
  83             return true;
  84         }
  85         return this->INHERITED::onQuery(evt);
  86     }
  87
  88     virtual void onDrawContent(SkCanvas* canvas) {
  89         const SkRect bounds = SkRect::MakeWH(W, H);
  90         static const SkAlpha gAlphaValue[] = { 0xFF, 0x88, 0x88 };
  91
  92         canvas->translate(SkIntToScalar(4), SkIntToScalar(4));
  93
  94         for (int alpha = 0; alpha < 4; ++alpha) {
  95             canvas->save();
  96             canvas->save();
  97             for (size_t i = 0; i < SK_ARRAY_COUNT(gModes); ++i) {
  98                 if (6 == i) {
  99                     canvas->restore();
 100                     canvas->translate(W * 5, 0);
 101                     canvas->save();
 102                 }
 103                 canvas->drawRect(bounds, fBGPaint);
 104                 canvas->saveLayer(&bounds, nullptr);
 105                 SkScalar dy = drawCell(canvas, gModes[i],
 106                                        gAlphaValue[alpha & 1],
 107                                        gAlphaValue[alpha & 2]);
 108                 canvas->restore();
 109
 110                 canvas->translate(0, dy * 5 / 4);
 111             }
 112             canvas->restore();
 113             canvas->restore();
 114             canvas->translate(W * 5 / 4, 0);
 115         }
 116     }
 117
 118 private:
 119     typedef SampleView INHERITED;
 120 };
 121
 122 ///////////////////////////////////////////////////////////////////////////////
 123
 124 static SkView* MyFactory() { return new HairModesView; }
 125 static SkViewRegister reg(MyFactory);