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(SK_ColorTRANSPARENT);
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_ColorTRANSPARENT, 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 void show_k_text(SkCanvas* canvas, SkScalar x, SkScalar y, const SkScalar k[]) {
58    SkPaint paint;
59    paint.setTextSize(SkIntToScalar(24));
60    paint.setAntiAlias(true);
61    for (int i = 0; i < 4; ++i) {
62        SkString str;
63        str.appendScalar(k[i]);
64        SkScalar width = paint.measureText(str.c_str(), str.size());
65        canvas->drawText(str.c_str(), str.size(), x, y + paint.getTextSize(), paint);
66        x += width + SkIntToScalar(10);
67    }
68}
69
70class ArithmodeGM : public skiagm::GM {
71public:
72    ArithmodeGM () {}
73
74protected:
75
76    virtual SkString onShortName() {
77        return SkString("arithmode");
78    }
79
80    virtual SkISize onISize() { return SkISize::Make(640, 480); }
81
82    virtual void onDraw(SkCanvas* canvas) {
83        SkBitmap src = make_src();
84        SkBitmap dst = make_dst();
85
86        const SkScalar one = SK_Scalar1;
87        static const SkScalar K[] = {
88            0, 0, 0, 0,
89            0, 0, 0, one,
90            0, one, 0, 0,
91            0, 0, one, 0,
92            0, one, one, 0,
93            0, one, -one, 0,
94            0, one/2, one/2, 0,
95            0, one/2, one/2, one/4,
96            0, one/2, one/2, -one/4,
97            one/4, one/2, one/2, 0,
98            -one/4, one/2, one/2, 0,
99        };
100
101        const SkScalar* k = K;
102        const SkScalar* stop = k + SK_ARRAY_COUNT(K);
103        SkScalar y = 0;
104        SkScalar gap = SkIntToScalar(src.width() + 20);
105        while (k < stop) {
106            SkScalar x = 0;
107            canvas->drawBitmap(src, x, y, NULL);
108            x += gap;
109            canvas->drawBitmap(dst, x, y, NULL);
110            x += gap;
111            SkRect rect = SkRect::MakeXYWH(x, y, SkIntToScalar(WW), SkIntToScalar(HH));
112            canvas->saveLayer(&rect, NULL);
113            canvas->drawBitmap(dst, x, y, NULL);
114            SkXfermode* xfer = SkArithmeticMode::Create(k[0], k[1], k[2], k[3]);
115            SkPaint paint;
116            paint.setXfermode(xfer)->unref();
117            canvas->drawBitmap(src, x, y, &paint);
118            canvas->restore();
119            x += gap;
120            show_k_text(canvas, x, y, k);
121            k += 4;
122            y += SkIntToScalar(src.height() + 12);
123        }
124    }
125
126private:
127    typedef GM INHERITED;
128};
129
130///////////////////////////////////////////////////////////////////////////////
131
132static skiagm::GM* MyFactory(void*) { return new ArithmodeGM; }
133static skiagm::GMRegistry reg(MyFactory);
134