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#include "SkArithmeticMode.h"
14#include "SkGradientShader.h"
15#define WW  100
16#define HH  32
17
18static SkBitmap make_bm() {
19    SkBitmap bm;
20    bm.setConfig(SkBitmap::kARGB_8888_Config, WW, HH);
21    bm.allocPixels();
22    bm.eraseColor(0);
23    return bm;
24}
25
26static SkBitmap make_src() {
27    SkBitmap bm = make_bm();
28    SkCanvas canvas(bm);
29    SkPaint paint;
30    SkPoint pts[] = { {0, 0}, {SkIntToScalar(WW), SkIntToScalar(HH)} };
31    SkColor colors[] = {
32        SK_ColorBLACK, SK_ColorGREEN, SK_ColorCYAN,
33        SK_ColorRED, SK_ColorMAGENTA, SK_ColorWHITE
34    };
35    SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, SK_ARRAY_COUNT(colors),
36                                                 SkShader::kClamp_TileMode);
37    paint.setShader(s)->unref();
38    canvas.drawPaint(paint);
39    return bm;
40}
41
42static SkBitmap make_dst() {
43    SkBitmap bm = make_bm();
44    SkCanvas canvas(bm);
45    SkPaint paint;
46    SkPoint pts[] = { {0, SkIntToScalar(HH)}, {SkIntToScalar(WW), 0} };
47    SkColor colors[] = {
48        SK_ColorBLUE, SK_ColorYELLOW, SK_ColorBLACK, SK_ColorGREEN, SK_ColorGRAY
49    };
50    SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, SK_ARRAY_COUNT(colors),
51                                                 SkShader::kClamp_TileMode);
52    paint.setShader(s)->unref();
53    canvas.drawPaint(paint);
54    return bm;
55}
56
57static SkBitmap make_arith(const SkBitmap& src, const SkBitmap& dst,
58                           const SkScalar k[]) {
59    SkBitmap bm = make_bm();
60    SkCanvas canvas(bm);
61    SkPaint paint;
62    canvas.drawBitmap(dst, 0, 0, NULL);
63    SkXfermode* xfer = SkArithmeticMode::Create(k[0], k[1], k[2], k[3]);
64    paint.setXfermode(xfer)->unref();
65    canvas.drawBitmap(src, 0, 0, &paint);
66    return bm;
67}
68
69static void show_k_text(SkCanvas* canvas, SkScalar x, SkScalar y, const SkScalar k[]) {
70    SkPaint paint;
71    paint.setTextSize(SkIntToScalar(24));
72    paint.setAntiAlias(true);
73    for (int i = 0; i < 4; ++i) {
74        SkString str;
75        str.appendScalar(k[i]);
76        SkScalar width = paint.measureText(str.c_str(), str.size());
77        canvas->drawText(str.c_str(), str.size(), x, y + paint.getTextSize(), paint);
78        x += width + SkIntToScalar(10);
79    }
80}
81
82class ArithmodeGM : public skiagm::GM {
83public:
84    ArithmodeGM () {}
85
86protected:
87
88    virtual SkString onShortName() {
89        return SkString("arithmode");
90    }
91
92    virtual SkISize onISize() { return SkISize::Make(640, 480); }
93
94    virtual void onDraw(SkCanvas* canvas) {
95        SkBitmap src = make_src();
96        SkBitmap dst = make_dst();
97
98        const SkScalar one = SK_Scalar1;
99        static const SkScalar K[] = {
100            0, 0, 0, 0,
101            0, 0, 0, one,
102            0, one, 0, 0,
103            0, 0, one, 0,
104            0, one, one, 0,
105            0, one, -one, 0,
106            0, one/2, one/2, 0,
107            0, one/2, one/2, one/4,
108            0, one/2, one/2, -one/4,
109            one/4, one/2, one/2, 0,
110            -one/4, one/2, one/2, 0,
111        };
112
113        const SkScalar* k = K;
114        const SkScalar* stop = k + SK_ARRAY_COUNT(K);
115        SkScalar y = 0;
116        SkScalar x = 0;
117        SkScalar gap = SkIntToScalar(src.width() + 20);
118        while (k < stop) {
119            SkScalar x = 0;
120            SkBitmap res = make_arith(src, dst, k);
121            canvas->drawBitmap(src, x, y, NULL);
122            x += gap;
123            canvas->drawBitmap(dst, x, y, NULL);
124            x += gap;
125            canvas->drawBitmap(res, x, y, NULL);
126            x += gap;
127            show_k_text(canvas, x, y, k);
128            k += 4;
129            y += SkIntToScalar(src.height() + 12);
130        }
131    }
132
133private:
134    typedef GM INHERITED;
135};
136
137///////////////////////////////////////////////////////////////////////////////
138
139static skiagm::GM* MyFactory(void*) { return new ArithmodeGM; }
140static skiagm::GMRegistry reg(MyFactory);
141