SampleShaders.cpp revision 82065d667f64e232bcde2ad849756a6096fcbe6f 
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 SkView {
44public:
45    SkShader*   fShader;
46    SkBitmap    fBitmap;
47
48	ShaderView()
49    {
50        SkImageDecoder::DecodeFile("/skimages/logo.gif", &fBitmap);
51
52        SkPoint pts[2];
53        SkColor colors[2];
54
55        pts[0].set(0, 0);
56        pts[1].set(SkIntToScalar(100), 0);
57        colors[0] = SK_ColorRED;
58        colors[1] = SK_ColorBLUE;
59        SkShader* shaderA = SkGradientShader::CreateLinear(pts, colors, NULL, 2, SkShader::kClamp_TileMode);
60
61        pts[0].set(0, 0);
62        pts[1].set(0, SkIntToScalar(100));
63        colors[0] = SK_ColorBLACK;
64        colors[1] = SkColorSetARGB(0x80, 0, 0, 0);
65        SkShader* shaderB = SkGradientShader::CreateLinear(pts, colors, NULL, 2, SkShader::kClamp_TileMode);
66
67        SkXfermode* mode = SkXfermode::Create(SkXfermode::kDstIn_Mode);
68
69        fShader = new SkComposeShader(shaderA, shaderB, mode);
70        shaderA->unref();
71        shaderB->unref();
72        mode->unref();
73    }
74    virtual ~ShaderView()
75    {
76        SkSafeUnref(fShader);
77    }
78
79protected:
80    // overrides from SkEventSink
81    virtual bool onQuery(SkEvent* evt) {
82        if (SampleCode::TitleQ(*evt)) {
83            SampleCode::TitleR(evt, "Shaders");
84            return true;
85        }
86        return this->INHERITED::onQuery(evt);
87    }
88
89    void drawBG(SkCanvas* canvas)
90    {
91//        canvas->drawColor(0xFFDDDDDD);
92        canvas->drawColor(SK_ColorWHITE);
93    }
94
95    virtual void onDraw(SkCanvas* canvas)
96    {
97        this->drawBG(canvas);
98
99        canvas->drawBitmap(fBitmap, 0, 0);
100
101        canvas->translate(SkIntToScalar(20), SkIntToScalar(120));
102
103        SkPaint paint;
104        SkRect  r;
105
106        paint.setColor(SK_ColorGREEN);
107        canvas->drawRectCoords(0, 0, SkIntToScalar(100), SkIntToScalar(100), paint);
108        paint.setShader(fShader);
109        canvas->drawRectCoords(0, 0, SkIntToScalar(100), SkIntToScalar(100), paint);
110
111        canvas->translate(SkIntToScalar(110), 0);
112
113        int w = fBitmap.width();
114        int h = fBitmap.height();
115        w = 120;
116        h = 80;
117        r.set(0, 0, SkIntToScalar(w), SkIntToScalar(h));
118
119        paint.setShader(NULL);
120        canvas->drawRect(r, paint);
121        paint.setShader(make_bitmapfade(fBitmap))->unref();
122        canvas->drawRect(r, paint);
123
124        paint.setShader(new SkTransparentShader)->unref();
125        canvas->drawRect(r, paint);
126    }
127
128    virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y)
129    {
130        this->inval(NULL);
131        return this->INHERITED::onFindClickHandler(x, y);
132    }
133
134    virtual bool onClick(Click* click)
135    {
136        return this->INHERITED::onClick(click);
137    }
138
139private:
140    typedef SkView INHERITED;
141};
142
143//////////////////////////////////////////////////////////////////////////////
144
145static SkView* MyFactory() { return new ShaderView; }
146static SkViewRegister reg(MyFactory);
147
148