SampleShaderText.cpp revision e2b193ca5c76f01f8e12b4a92e9bd6ccb3ed4280 
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 "SkUnitMappers.h"
13
14static void makebm(SkBitmap* bm, int w, int h) {
15    bm->allocN32Pixels(w, h);
16    bm->eraseColor(SK_ColorTRANSPARENT);
17
18    SkCanvas    canvas(*bm);
19    SkScalar s = SkIntToScalar(w < h ? w : h);
20    SkPoint     pts[] = { { 0, 0 }, { s, s } };
21    SkColor     colors[] = { SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE };
22    SkScalar    pos[] = { 0, SK_Scalar1/2, SK_Scalar1 };
23    SkPaint     paint;
24
25    SkUnitMapper*   um = NULL;
26
27    um = new SkCosineMapper;
28
29    SkAutoUnref au(um);
30
31    paint.setDither(true);
32    paint.setShader(SkGradientShader::CreateLinear(pts, colors, pos,
33                SK_ARRAY_COUNT(colors), SkShader::kClamp_TileMode, um))->unref();
34    canvas.drawPaint(paint);
35}
36
37static SkShader* MakeBitmapShader(SkShader::TileMode tx, SkShader::TileMode ty,
38                           int w, int h) {
39    static SkBitmap bmp;
40    if (bmp.isNull()) {
41        makebm(&bmp, w/2, h/4);
42    }
43    return SkShader::CreateBitmapShader(bmp, tx, ty);
44}
45
46///////////////////////////////////////////////////////////////////////////////
47
48struct GradData {
49    int             fCount;
50    const SkColor*  fColors;
51    const SkScalar* fPos;
52};
53
54static const SkColor gColors[] = {
55    SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorWHITE, SK_ColorBLACK
56};
57
58static const GradData gGradData[] = {
59    { 2, gColors, NULL },
60    { 5, gColors, NULL },
61};
62
63static SkShader* MakeLinear(const SkPoint pts[2], const GradData& data,
64                            SkShader::TileMode tm, SkUnitMapper* mapper) {
65    return SkGradientShader::CreateLinear(pts, data.fColors, data.fPos,
66                                          data.fCount, tm, mapper);
67}
68
69static SkShader* MakeRadial(const SkPoint pts[2], const GradData& data,
70                            SkShader::TileMode tm, SkUnitMapper* mapper) {
71    SkPoint center;
72    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
73               SkScalarAve(pts[0].fY, pts[1].fY));
74    return SkGradientShader::CreateRadial(center, center.fX, data.fColors,
75                                          data.fPos, data.fCount, tm, mapper);
76}
77
78static SkShader* MakeSweep(const SkPoint pts[2], const GradData& data,
79                           SkShader::TileMode tm, SkUnitMapper* mapper) {
80    SkPoint center;
81    center.set(SkScalarAve(pts[0].fX, pts[1].fX),
82               SkScalarAve(pts[0].fY, pts[1].fY));
83    return SkGradientShader::CreateSweep(center.fX, center.fY, data.fColors,
84                                         data.fPos, data.fCount, mapper);
85}
86
87static SkShader* Make2Radial(const SkPoint pts[2], const GradData& data,
88                           SkShader::TileMode tm, SkUnitMapper* mapper) {
89    SkPoint center0, center1;
90    center0.set(SkScalarAve(pts[0].fX, pts[1].fX),
91                SkScalarAve(pts[0].fY, pts[1].fY));
92    center1.set(SkScalarInterp(pts[0].fX, pts[1].fX, SkIntToScalar(3)/5),
93                SkScalarInterp(pts[0].fY, pts[1].fY, SkIntToScalar(1)/4));
94    return SkGradientShader::CreateTwoPointRadial(
95                            center1, (pts[1].fX - pts[0].fX) / 7,
96                            center0, (pts[1].fX - pts[0].fX) / 2,
97                            data.fColors, data.fPos, data.fCount, tm, mapper);
98}
99
100typedef SkShader* (*GradMaker)(const SkPoint pts[2], const GradData& data,
101                     SkShader::TileMode tm, SkUnitMapper* mapper);
102static const GradMaker gGradMakers[] = {
103    MakeLinear, MakeRadial, MakeSweep, Make2Radial
104};
105
106///////////////////////////////////////////////////////////////////////////////
107
108class ShaderTextView : public SampleView {
109public:
110    ShaderTextView() {
111        this->setBGColor(0xFFDDDDDD);
112    }
113
114protected:
115    // overrides from SkEventSink
116    virtual bool onQuery(SkEvent* evt) {
117        if (SampleCode::TitleQ(*evt)) {
118            SampleCode::TitleR(evt, "Shader Text");
119            return true;
120        }
121        return this->INHERITED::onQuery(evt);
122    }
123
124    virtual void onDrawContent(SkCanvas* canvas) {
125        const char text[] = "Shaded Text";
126        const int textLen = SK_ARRAY_COUNT(text) - 1;
127        static int pointSize = 36;
128
129        int w = pointSize * textLen;
130        int h = pointSize;
131
132        SkPoint pts[2] = {
133            { 0, 0 },
134            { SkIntToScalar(w), SkIntToScalar(h) }
135        };
136        SkScalar textBase = SkIntToScalar(h/2);
137
138        SkShader::TileMode tileModes[] = {
139            SkShader::kClamp_TileMode,
140            SkShader::kRepeat_TileMode,
141            SkShader::kMirror_TileMode
142        };
143
144        static const int gradCount = SK_ARRAY_COUNT(gGradData) *
145                                     SK_ARRAY_COUNT(gGradMakers);
146        static const int bmpCount = SK_ARRAY_COUNT(tileModes) *
147                                    SK_ARRAY_COUNT(tileModes);
148        SkShader* shaders[gradCount + bmpCount];
149
150        int shdIdx = 0;
151        for (size_t d = 0; d < SK_ARRAY_COUNT(gGradData); ++d) {
152            for (size_t m = 0; m < SK_ARRAY_COUNT(gGradMakers); ++m) {
153                shaders[shdIdx++] = gGradMakers[m](pts,
154                                                   gGradData[d],
155                                                   SkShader::kClamp_TileMode,
156                                                   NULL);
157            }
158        }
159        for (size_t tx = 0; tx < SK_ARRAY_COUNT(tileModes); ++tx) {
160            for (size_t ty = 0; ty < SK_ARRAY_COUNT(tileModes); ++ty) {
161                shaders[shdIdx++] = MakeBitmapShader(tileModes[tx],
162                                                     tileModes[ty],
163                                                     w/8, h);
164            }
165        }
166
167        SkPaint paint;
168        paint.setDither(true);
169        paint.setAntiAlias(true);
170        paint.setTextSize(SkIntToScalar(pointSize));
171
172        canvas->save();
173        canvas->translate(SkIntToScalar(20), SkIntToScalar(10));
174
175        SkPath path;
176        path.arcTo(SkRect::MakeXYWH(SkIntToScalar(-40), SkIntToScalar(15),
177                                    SkIntToScalar(300), SkIntToScalar(90)),
178                                    SkIntToScalar(225), SkIntToScalar(90),
179                                    false);
180        path.close();
181
182        static const int testsPerCol = 8;
183        static const int rowHeight = 60;
184        static const int colWidth = 300;
185        canvas->save();
186        for (size_t s = 0; s < SK_ARRAY_COUNT(shaders); s++) {
187            canvas->save();
188            size_t i = 2*s;
189            canvas->translate(SkIntToScalar((i / testsPerCol) * colWidth),
190                              SkIntToScalar((i % testsPerCol) * rowHeight));
191            paint.setShader(shaders[s])->unref();
192            canvas->drawText(text, textLen, 0, textBase, paint);
193            canvas->restore();
194            canvas->save();
195            ++i;
196            canvas->translate(SkIntToScalar((i / testsPerCol) * colWidth),
197                              SkIntToScalar((i % testsPerCol) * rowHeight));
198            canvas->drawTextOnPath(text, textLen, path, NULL, paint);
199            canvas->restore();
200        }
201        canvas->restore();
202
203        canvas->translate(0, SkIntToScalar(370));
204        this->inval(NULL);
205    }
206
207private:
208    typedef SampleView INHERITED;
209};
210
211///////////////////////////////////////////////////////////////////////////////
212
213static SkView* MyFactory() { return new ShaderTextView; }
214static SkViewRegister reg(MyFactory);
215