1/*
2 * Copyright 2013 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
10#include "Resources.h"
11#include "SampleCode.h"
12#include "SkBlurMask.h"
13#include "SkBlurDrawLooper.h"
14#include "SkCanvas.h"
15#include "SkColorPriv.h"
16#include "SkForceLinking.h"
17#include "SkImageDecoder.h"
18#include "SkOSFile.h"
19#include "SkStream.h"
20#include "SkString.h"
21#include "SkSystemEventTypes.h"
22#include "SkTypes.h"
23#include "SkUtils.h"
24#include "SkView.h"
25
26__SK_FORCE_IMAGE_DECODER_LINKING;
27
28// Defined in SampleColorFilter.cpp
29extern SkShader* createChecker();
30
31/**
32 *  Interprets c as an unpremultiplied color, and returns the
33 *  premultiplied equivalent.
34 */
35static SkPMColor premultiply_unpmcolor(SkPMColor c) {
36    U8CPU a = SkGetPackedA32(c);
37    U8CPU r = SkGetPackedR32(c);
38    U8CPU g = SkGetPackedG32(c);
39    U8CPU b = SkGetPackedB32(c);
40    return SkPreMultiplyARGB(a, r, g, b);
41}
42
43class UnpremulView : public SampleView {
44public:
45    UnpremulView(SkString res)
46    : fResPath(res)
47    , fPremul(true)
48    , fDecodeSucceeded(false) {
49        this->nextImage();
50    }
51
52protected:
53    // overrides from SkEventSink
54    virtual bool onQuery(SkEvent* evt) SK_OVERRIDE {
55        if (SampleCode::TitleQ(*evt)) {
56            SampleCode::TitleR(evt, "unpremul");
57            return true;
58        }
59        SkUnichar uni;
60        if (SampleCode::CharQ(*evt, &uni)) {
61            char utf8[kMaxBytesInUTF8Sequence];
62            size_t size = SkUTF8_FromUnichar(uni, utf8);
63            // Only consider events for single char keys
64            if (1 == size) {
65                switch (utf8[0]) {
66                    case fNextImageChar:
67                        this->nextImage();
68                        return true;
69                    case fTogglePremulChar:
70                        this->togglePremul();
71                        return true;
72                    default:
73                        break;
74                }
75            }
76        }
77        return this->INHERITED::onQuery(evt);
78    }
79
80    virtual void onDrawBackground(SkCanvas* canvas) SK_OVERRIDE {
81        SkPaint paint;
82        SkAutoTUnref<SkShader> shader(createChecker());
83        paint.setShader(shader.get());
84        canvas->drawPaint(paint);
85    }
86
87    virtual void onDrawContent(SkCanvas* canvas) SK_OVERRIDE {
88        SkPaint paint;
89        paint.setAntiAlias(true);
90        paint.setTextSize(SkIntToScalar(24));
91        SkAutoTUnref<SkBlurDrawLooper> looper(
92            SkBlurDrawLooper::Create(SK_ColorBLUE,
93                                     SkBlurMask::ConvertRadiusToSigma(SkIntToScalar(2)),
94                                     0, 0));
95        paint.setLooper(looper);
96        SkScalar height = paint.getFontMetrics(NULL);
97        if (!fDecodeSucceeded) {
98            SkString failure;
99            if (fResPath.size() == 0) {
100                failure.printf("resource path is required!");
101            } else {
102                failure.printf("Failed to decode %s", fCurrFile.c_str());
103            }
104            canvas->drawText(failure.c_str(), failure.size(), 0, height, paint);
105            return;
106        }
107
108        // Name, size of the file, and whether or not it is premultiplied.
109        SkString header(SkOSPath::SkBasename(fCurrFile.c_str()));
110        header.appendf("     [%dx%d]     %s", fBitmap.width(), fBitmap.height(),
111                       (fPremul ? "premultiplied" : "unpremultiplied"));
112        canvas->drawText(header.c_str(), header.size(), 0, height, paint);
113        canvas->translate(0, height);
114
115        // Help messages
116        header.printf("Press '%c' to move to the next image.'", fNextImageChar);
117        canvas->drawText(header.c_str(), header.size(), 0, height, paint);
118        canvas->translate(0, height);
119
120        header.printf("Press '%c' to toggle premultiplied decode.", fTogglePremulChar);
121        canvas->drawText(header.c_str(), header.size(), 0, height, paint);
122
123        // Now draw the image itself.
124        canvas->translate(height * 2, height * 2);
125        if (!fPremul) {
126            // A premultiplied bitmap cannot currently be drawn.
127            SkAutoLockPixels alp(fBitmap);
128            // Copy it to a bitmap which can be drawn, converting
129            // to premultiplied:
130            SkBitmap bm;
131            if (!bm.allocN32Pixels(fBitmap.width(), fBitmap.height())) {
132                SkString errMsg("allocPixels failed");
133                canvas->drawText(errMsg.c_str(), errMsg.size(), 0, height, paint);
134                return;
135            }
136            for (int i = 0; i < fBitmap.width(); ++i) {
137                for (int j = 0; j < fBitmap.height(); ++j) {
138                    *bm.getAddr32(i, j) = premultiply_unpmcolor(*fBitmap.getAddr32(i, j));
139                }
140            }
141            canvas->drawBitmap(bm, 0, 0);
142        } else {
143            canvas->drawBitmap(fBitmap, 0, 0);
144        }
145    }
146
147private:
148    const SkString  fResPath;
149    SkString        fCurrFile;
150    bool            fPremul;
151    bool            fDecodeSucceeded;
152    SkBitmap        fBitmap;
153    SkOSFile::Iter  fFileIter;
154
155    static const char   fNextImageChar      = 'j';
156    static const char   fTogglePremulChar   = 'h';
157
158    void nextImage() {
159        if (fResPath.size() == 0) {
160            return;
161        }
162        SkString basename;
163        if (!fFileIter.next(&basename)) {
164            fFileIter.reset(fResPath.c_str());
165            if (!fFileIter.next(&basename)) {
166                // Perhaps this should draw some error message?
167                return;
168            }
169        }
170        fCurrFile = SkOSPath::SkPathJoin(fResPath.c_str(), basename.c_str());
171        this->decodeCurrFile();
172    }
173
174    void decodeCurrFile() {
175        if (fCurrFile.size() == 0) {
176            fDecodeSucceeded = false;
177            return;
178        }
179        SkFILEStream stream(fCurrFile.c_str());
180        SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(&stream));
181        if (NULL == decoder.get()) {
182            fDecodeSucceeded = false;
183            return;
184        }
185        if (!fPremul) {
186            decoder->setRequireUnpremultipliedColors(true);
187        }
188        fDecodeSucceeded = decoder->decode(&stream, &fBitmap, kN32_SkColorType,
189                                           SkImageDecoder::kDecodePixels_Mode);
190        this->inval(NULL);
191    }
192
193    void togglePremul() {
194        fPremul = !fPremul;
195        this->decodeCurrFile();
196    }
197
198    typedef SampleView INHERITED;
199};
200
201//////////////////////////////////////////////////////////////////////////////
202
203static SkView* MyFactory() {
204    return new UnpremulView(GetResourcePath());
205}
206static SkViewRegister reg(MyFactory);
207