1
2/*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8#include "SampleCode.h"
9#include "SkView.h"
10#include "SkCanvas.h"
11#include "SkGradientShader.h"
12#include "SkPath.h"
13#include "SkRegion.h"
14#include "SkShader.h"
15#include "SkUtils.h"
16#include "Sk1DPathEffect.h"
17#include "SkCornerPathEffect.h"
18#include "SkPathMeasure.h"
19#include "SkRandom.h"
20#include "SkColorPriv.h"
21#include "SkColorFilter.h"
22#include "SkDither.h"
23
24static void draw_sweep(SkCanvas* c, int width, int height, SkScalar angle) {
25    SkRect  r;
26    SkPaint p;
27
28    p.setAntiAlias(true);
29//    p.setDither(true);
30    p.setStrokeWidth(SkIntToScalar(width/10));
31    p.setStyle(SkPaint::kStroke_Style);
32
33    r.set(0, 0, SkIntToScalar(width), SkIntToScalar(height));
34
35    //    SkColor colors[] = { SK_ColorRED, SK_ColorBLUE, SK_ColorGREEN, SK_ColorCYAN };
36    SkColor colors[] = { 0x4c737373, 0x4c737373, 0xffffd300 };
37    SkShader* s = SkGradientShader::CreateSweep(r.centerX(), r.centerY(),
38                                                colors, NULL, SK_ARRAY_COUNT(colors));
39    p.setShader(s)->unref();
40
41    SkAutoCanvasRestore acr(c, true);
42
43    c->translate(r.centerX(), r.centerY());
44    c->rotate(angle);
45    c->translate(-r.centerX(), -r.centerY());
46
47    SkRect bounds = r;
48    r.inset(p.getStrokeWidth(), p.getStrokeWidth());
49    SkRect innerBounds = r;
50
51    if (true) {
52        c->drawOval(r, p);
53    } else {
54        SkScalar x = r.centerX();
55        SkScalar y = r.centerY();
56        SkScalar radius = r.width() / 2;
57        SkScalar thickness = p.getStrokeWidth();
58        SkScalar sweep = 360.0f;
59        SkPath path;
60
61        path.moveTo(x + radius, y);
62        // outer top
63        path.lineTo(x + radius + thickness, y);
64        // outer arc
65        path.arcTo(bounds, 0, sweep, false);
66        // inner arc
67        path.arcTo(innerBounds, sweep, -sweep, false);
68        path.close();
69    }
70}
71
72static void make_bm(SkBitmap* bm) {
73    bm->allocN32Pixels(100, 100);
74    bm->eraseColor(SK_ColorTRANSPARENT);
75
76    SkCanvas c(*bm);
77    draw_sweep(&c, bm->width(), bm->height(), 0);
78}
79
80static void pre_dither(const SkBitmap& bm) {
81    SkAutoLockPixels alp(bm);
82
83    for (int y = 0; y < bm.height(); y++) {
84        DITHER_4444_SCAN(y);
85
86        SkPMColor* p = bm.getAddr32(0, y);
87        for (int x = 0; x < bm.width(); x++) {
88            SkPMColor c = *p;
89
90            unsigned a = SkGetPackedA32(c);
91            unsigned r = SkGetPackedR32(c);
92            unsigned g = SkGetPackedG32(c);
93            unsigned b = SkGetPackedB32(c);
94
95            unsigned d = DITHER_VALUE(x);
96
97            a = SkDITHER_A32To4444(a, d);
98            r = SkDITHER_R32To4444(r, d);
99            g = SkDITHER_G32To4444(g, d);
100            b = SkDITHER_B32To4444(b, d);
101
102            a = SkA4444ToA32(a);
103            r = SkR4444ToR32(r);
104            g = SkG4444ToG32(g);
105            b = SkB4444ToB32(b);
106
107            *p++ = SkPackARGB32(a, r, g, b);
108        }
109    }
110}
111
112class DitherView : public SampleView {
113public:
114    SkBitmap    fBM, fBMPreDither, fBM16;
115    SkScalar fAngle;
116
117    DitherView() {
118        make_bm(&fBM);
119        make_bm(&fBMPreDither);
120        pre_dither(fBMPreDither);
121        fBM.copyTo(&fBM16, kARGB_4444_SkColorType);
122
123        fAngle = 0;
124
125        this->setBGColor(0xFF181818);
126    }
127
128protected:
129    // overrides from SkEventSink
130    virtual bool onQuery(SkEvent* evt) {
131        if (SampleCode::TitleQ(*evt)) {
132            SampleCode::TitleR(evt, "Dither");
133            return true;
134        }
135        return this->INHERITED::onQuery(evt);
136    }
137
138    virtual void onDrawContent(SkCanvas* canvas) {
139        SkPaint paint;
140        SkScalar x = SkIntToScalar(10);
141        SkScalar y = SkIntToScalar(10);
142        const SkScalar DX = SkIntToScalar(fBM.width() + 10);
143
144        paint.setAntiAlias(true);
145
146        if (true) {
147            canvas->drawBitmap(fBM, x, y, &paint);
148            x += DX;
149            paint.setDither(true);
150            canvas->drawBitmap(fBM, x, y, &paint);
151
152            x += DX;
153            paint.setDither(false);
154            canvas->drawBitmap(fBMPreDither, x, y, &paint);
155
156            x += DX;
157            canvas->drawBitmap(fBM16, x, y, &paint);
158        }
159
160        canvas->translate(DX, DX*2);
161        draw_sweep(canvas, fBM.width(), fBM.height(), fAngle);
162        canvas->translate(DX, 0);
163        draw_sweep(canvas, fBM.width()>>1, fBM.height()>>1, fAngle);
164        canvas->translate(DX, 0);
165        draw_sweep(canvas, fBM.width()>>2, fBM.height()>>2, fAngle);
166
167        fAngle += SK_Scalar1/2;
168        this->inval(NULL);
169    }
170
171private:
172    typedef SampleView INHERITED;
173};
174
175//////////////////////////////////////////////////////////////////////////////
176
177static SkView* MyFactory() { return new DitherView; }
178static SkViewRegister reg(MyFactory);
179