SampleShaders.cpp revision 5fd9243fd6b82aa3f2a2fae7c62310e77ab7b6d3 
1#include "SampleCode.h"
2#include "SkView.h"
3#include "SkCanvas.h"
4#include "SkGradientShader.h"
5#include "SkGraphics.h"
6#include "SkImageDecoder.h"
7#include "SkPath.h"
8#include "SkRegion.h"
9#include "SkShader.h"
10#include "SkUtils.h"
11#include "SkXfermode.h"
12#include "SkComposeShader.h"
13#include "SkColorPriv.h"
14#include "SkColorFilter.h"
15#include "SkTime.h"
16#include "SkTransparentShader.h"
17#include "SkTypeface.h"
18
19static SkShader* make_bitmapfade(const SkBitmap& bm)
20{
21    SkPoint pts[2];
22    SkColor colors[2];
23
24    pts[0].set(0, 0);
25    pts[1].set(0, SkIntToScalar(bm.height()));
26    colors[0] = SK_ColorBLACK;
27    colors[1] = SkColorSetARGB(0, 0, 0, 0);
28    SkShader* shaderA = SkGradientShader::CreateLinear(pts, colors, NULL, 2, SkShader::kClamp_TileMode);
29
30    SkShader* shaderB = SkShader::CreateBitmapShader(bm,
31                        SkShader::kClamp_TileMode, SkShader::kClamp_TileMode);
32
33    SkXfermode* mode = SkXfermode::Create(SkXfermode::kDstIn_Mode);
34
35    SkShader* shader = new SkComposeShader(shaderB, shaderA, mode);
36    shaderA->unref();
37    shaderB->unref();
38    mode->unref();
39
40    return shader;
41}
42
43class ShaderView : public SampleView {
44public:
45    SkShader*   fShader;
46    SkBitmap    fBitmap;
47
48	ShaderView() {
49        SkImageDecoder::DecodeFile("/skimages/logo.gif", &fBitmap);
50
51        SkPoint pts[2];
52        SkColor colors[2];
53
54        pts[0].set(0, 0);
55        pts[1].set(SkIntToScalar(100), 0);
56        colors[0] = SK_ColorRED;
57        colors[1] = SK_ColorBLUE;
58        SkShader* shaderA = SkGradientShader::CreateLinear(pts, colors, NULL, 2, SkShader::kClamp_TileMode);
59
60        pts[0].set(0, 0);
61        pts[1].set(0, SkIntToScalar(100));
62        colors[0] = SK_ColorBLACK;
63        colors[1] = SkColorSetARGB(0x80, 0, 0, 0);
64        SkShader* shaderB = SkGradientShader::CreateLinear(pts, colors, NULL, 2, SkShader::kClamp_TileMode);
65
66        SkXfermode* mode = SkXfermode::Create(SkXfermode::kDstIn_Mode);
67
68        fShader = new SkComposeShader(shaderA, shaderB, mode);
69        shaderA->unref();
70        shaderB->unref();
71        mode->unref();
72    }
73    virtual ~ShaderView() {
74        SkSafeUnref(fShader);
75    }
76
77protected:
78    // overrides from SkEventSink
79    virtual bool onQuery(SkEvent* evt) {
80        if (SampleCode::TitleQ(*evt)) {
81            SampleCode::TitleR(evt, "Shaders");
82            return true;
83        }
84        return this->INHERITED::onQuery(evt);
85    }
86
87    virtual void onDrawContent(SkCanvas* canvas) {
88        canvas->drawBitmap(fBitmap, 0, 0);
89
90        canvas->translate(SkIntToScalar(20), SkIntToScalar(120));
91
92        SkPaint paint;
93        SkRect  r;
94
95        paint.setColor(SK_ColorGREEN);
96        canvas->drawRectCoords(0, 0, SkIntToScalar(100), SkIntToScalar(100), paint);
97        paint.setShader(fShader);
98        canvas->drawRectCoords(0, 0, SkIntToScalar(100), SkIntToScalar(100), paint);
99
100        canvas->translate(SkIntToScalar(110), 0);
101
102        int w = fBitmap.width();
103        int h = fBitmap.height();
104        w = 120;
105        h = 80;
106        r.set(0, 0, SkIntToScalar(w), SkIntToScalar(h));
107
108        paint.setShader(NULL);
109        canvas->drawRect(r, paint);
110        paint.setShader(make_bitmapfade(fBitmap))->unref();
111        canvas->drawRect(r, paint);
112
113        paint.setShader(new SkTransparentShader)->unref();
114        canvas->drawRect(r, paint);
115    }
116
117    virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y) {
118        this->inval(NULL);
119        return this->INHERITED::onFindClickHandler(x, y);
120    }
121
122    virtual bool onClick(Click* click) {
123        return this->INHERITED::onClick(click);
124    }
125
126private:
127    typedef SampleView INHERITED;
128};
129
130//////////////////////////////////////////////////////////////////////////////
131
132static SkView* MyFactory() { return new ShaderView; }
133static SkViewRegister reg(MyFactory);
134
135