hairmodes.cpp revision 0591897548c8fcb7d53cc94053e01702e58f1ac5 
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
13constexpr struct {
14    SkBlendMode fMode;
15    const char* fLabel;
16} gModes[] = {
17    { SkBlendMode::kClear,    "Clear"     },
18    { SkBlendMode::kSrc,      "Src"       },
19    { SkBlendMode::kDst,      "Dst"       },
20    { SkBlendMode::kSrcOver,  "SrcOver"   },
21    { SkBlendMode::kDstOver,  "DstOver"   },
22    { SkBlendMode::kSrcIn,    "SrcIn"     },
23    { SkBlendMode::kDstIn,    "DstIn"     },
24    { SkBlendMode::kSrcOut,   "SrcOut"    },
25    { SkBlendMode::kDstOut,   "DstOut"    },
26    { SkBlendMode::kSrcATop,  "SrcATop"   },
27    { SkBlendMode::kDstATop,  "DstATop"   },
28    { SkBlendMode::kXor,      "Xor"       },
29};
30
31const int gWidth = 64;
32const int gHeight = 64;
33const SkScalar W = SkIntToScalar(gWidth);
34const SkScalar H = SkIntToScalar(gHeight);
35
36static SkScalar drawCell(SkCanvas* canvas, SkBlendMode mode, SkAlpha a0, SkAlpha a1) {
37
38    SkPaint paint;
39    paint.setAntiAlias(true);
40
41    SkRect r = SkRect::MakeWH(W, H);
42    r.inset(W/10, H/10);
43
44    paint.setColor(SK_ColorBLUE);
45    paint.setAlpha(a0);
46    canvas->drawOval(r, paint);
47
48    paint.setColor(SK_ColorRED);
49    paint.setAlpha(a1);
50    paint.setBlendMode(mode);
51    for (int angle = 0; angle < 24; ++angle) {
52        SkScalar x = SkScalarCos(SkIntToScalar(angle) * (SK_ScalarPI * 2) / 24) * gWidth;
53        SkScalar y = SkScalarSin(SkIntToScalar(angle) * (SK_ScalarPI * 2) / 24) * gHeight;
54        paint.setStrokeWidth(SK_Scalar1 * angle * 2 / 24);
55        canvas->drawLine(W/2, H/2, W/2 + x, H/2 + y, paint);
56    }
57
58    return H;
59}
60
61static sk_sp<SkShader> make_bg_shader() {
62    SkBitmap bm;
63    bm.allocN32Pixels(2, 2);
64    *bm.getAddr32(0, 0) = *bm.getAddr32(1, 1) = 0xFFFFFFFF;
65    *bm.getAddr32(1, 0) = *bm.getAddr32(0, 1) = SkPackARGB32(0xFF, 0xCE, 0xCF, 0xCE);
66
67    SkMatrix m;
68    m.setScale(SkIntToScalar(6), SkIntToScalar(6));
69    return SkShader::MakeBitmapShader(bm,
70                                      SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode, &m);
71}
72
73namespace skiagm {
74
75    class HairModesGM : public GM {
76        SkPaint fBGPaint;
77
78    protected:
79        SkString onShortName() override {
80            return SkString("hairmodes");
81        }
82
83        virtual SkISize onISize() override { return SkISize::Make(640, 480); }
84
85        void onOnceBeforeDraw() override {
86            fBGPaint.setShader(make_bg_shader());
87        }
88
89        void onDraw(SkCanvas* canvas) override {
90            const SkRect bounds = SkRect::MakeWH(W, H);
91            constexpr SkAlpha gAlphaValue[] = { 0xFF, 0x88, 0x88 };
92
93            canvas->translate(SkIntToScalar(4), SkIntToScalar(4));
94
95            for (int alpha = 0; alpha < 4; ++alpha) {
96                canvas->save();
97                canvas->save();
98                for (size_t i = 0; i < SK_ARRAY_COUNT(gModes); ++i) {
99                    if (6 == i) {
100                        canvas->restore();
101                        canvas->translate(W * 5, 0);
102                        canvas->save();
103                    }
104
105                    canvas->drawRect(bounds, fBGPaint);
106                    canvas->saveLayer(&bounds, nullptr);
107                    SkScalar dy = drawCell(canvas, gModes[i].fMode,
108                                           gAlphaValue[alpha & 1],
109                                           gAlphaValue[alpha & 2]);
110                    canvas->restore();
111
112                    canvas->translate(0, dy * 5 / 4);
113                }
114                canvas->restore();
115                canvas->restore();
116                canvas->translate(W * 5 / 4, 0);
117            }
118        }
119
120    private:
121        typedef GM INHERITED;
122    };
123
124    //////////////////////////////////////////////////////////////////////////////
125
126    static GM* MyFactory(void*) { return new HairModesGM; }
127    static GMRegistry reg(MyFactory);
128
129}
130