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      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 }
    127