aboutsummaryrefslogtreecommitdiffhomepage
path: root/gm/animatedGif.cpp
blob: 03bf66c5261c4b672084693541acf2b7fff4722a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
/*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "gm.h"
#include "SkAnimTimer.h"
#include "SkCanvas.h"
#include "SkCodec.h"
#include "SkColor.h"
#include "SkCommandLineFlags.h"
#include "SkPaint.h"
#include "SkString.h"
#include "Resources.h"

#include <vector>

DEFINE_string(animatedGif, "test640x479.gif", "Animated gif in resources folder");

namespace {
    void error(SkCanvas* canvas, const SkString& errorText) {
        constexpr SkScalar kOffset = 5.0f;
        canvas->drawColor(SK_ColorRED);
        SkPaint paint;
        SkRect bounds;
        paint.measureText(errorText.c_str(), errorText.size(), &bounds);
        canvas->drawText(errorText.c_str(), errorText.size(), kOffset, bounds.height() + kOffset,
                         paint);
    }
}

class AnimatedGifGM : public skiagm::GM {
private:
    std::unique_ptr<SkCodec>        fCodec;
    size_t                          fFrame;
    double                          fNextUpdate;
    size_t                          fTotalFrames;
    std::vector<SkCodec::FrameInfo> fFrameInfos;
    std::vector<SkBitmap>           fFrames;

    void drawFrame(SkCanvas* canvas, int frameIndex) {
        // FIXME: Create from an Image/ImageGenerator?
        if (frameIndex >= (int) fFrames.size()) {
            fFrames.resize(frameIndex + 1);
        }
        SkBitmap& bm = fFrames[frameIndex];
        if (!bm.getPixels()) {
            const SkImageInfo info = fCodec->getInfo().makeColorType(kN32_SkColorType);
            bm.allocPixels(info);

            SkCodec::Options opts;
            opts.fFrameIndex = frameIndex;
            opts.fHasPriorFrame = false;
            const size_t requiredFrame = fFrameInfos[frameIndex].fRequiredFrame;
            if (requiredFrame != SkCodec::kNone) {
                SkASSERT(requiredFrame < fFrames.size());
                SkBitmap& requiredBitmap = fFrames[requiredFrame];
                // For simplicity, do not try to cache old frames
                if (requiredBitmap.getPixels() && requiredBitmap.copyTo(&bm)) {
                    opts.fHasPriorFrame = true;
                }
            }

            if (SkCodec::kSuccess != fCodec->getPixels(info, bm.getPixels(),
                                                       bm.rowBytes(), &opts,
                                                       nullptr, nullptr)) {
                SkDebugf("Could not getPixels for frame %i: %s", frameIndex, FLAGS_animatedGif[0]);
                return;
            }
        }

        canvas->drawBitmap(bm, 0, 0);
    }

public:
    AnimatedGifGM()
    : fFrame(0)
    , fNextUpdate (-1)
    , fTotalFrames (-1) {}

private:
    SkString onShortName() override {
        return SkString("animatedGif");
    }

    SkISize onISize() override {
        if (this->initCodec()) {
            SkISize dim = fCodec->getInfo().dimensions();
            // Wide enough to display all the frames.
            dim.fWidth *= fTotalFrames;
            // Tall enough to show the row of frames plus an animating version.
            dim.fHeight *= 2;
            return dim;
        }
        return SkISize::Make(640, 480);
    }

    void onDrawBackground(SkCanvas* canvas) override {
        canvas->clear(SK_ColorWHITE);
        if (this->initCodec()) {
            SkAutoCanvasRestore acr(canvas, true);
            for (size_t frameIndex = 0; frameIndex < fTotalFrames; frameIndex++) {
                this->drawFrame(canvas, frameIndex);
                canvas->translate(SkIntToScalar(fCodec->getInfo().width()), 0);
            }
        }
    }

    bool initCodec() {
        if (fCodec) {
            return true;
        }
        if (FLAGS_animatedGif.isEmpty()) {
            SkDebugf("Nothing specified for --animatedGif!");
            return false;
        }

        std::unique_ptr<SkStream> stream(GetResourceAsStream(FLAGS_animatedGif[0]));
        if (!stream) {
            return false;
        }

        fCodec.reset(SkCodec::NewFromStream(stream.release()));
        if (!fCodec) {
            SkDebugf("Could create codec from %s", FLAGS_animatedGif[0]);
            return false;
        }

        fFrame = 0;
        fFrameInfos = fCodec->getFrameInfo();
        fTotalFrames = fFrameInfos.size();
        return true;
    }

    void onDraw(SkCanvas* canvas) override {
        if (!fCodec) {
            SkString errorText = SkStringPrintf("Nothing to draw; %s", FLAGS_animatedGif[0]);
            error(canvas, errorText);
            return;
        }

        SkAutoCanvasRestore acr(canvas, true);
        canvas->translate(0, SkIntToScalar(fCodec->getInfo().height()));
        this->drawFrame(canvas, fFrame);
    }

    bool onAnimate(const SkAnimTimer& timer) override {
        if (!fCodec || fTotalFrames == 1) {
            return false;
        }

        double secs = timer.msec() * .1;
        if (fNextUpdate < double(0)) {
            // This is a sentinel that we have not done any updates yet.
            // I'm assuming this gets called *after* onOnceBeforeDraw, so our first frame should
            // already have been retrieved.
            SkASSERT(fFrame == 0);
            fNextUpdate = secs + fFrameInfos[fFrame].fDuration;

            return true;
        }

        if (secs < fNextUpdate) {
            return true;
        }

        while (secs >= fNextUpdate) {
            // Retrieve the next frame.
            fFrame++;
            if (fFrame == fTotalFrames) {
                fFrame = 0;
            }

            // Note that we loop here. This is not safe if we need to draw the intermediate frame
            // in order to draw correctly.
            fNextUpdate += fFrameInfos[fFrame].fDuration;
        }

        return true;
    }
};

DEF_GM(return new AnimatedGifGM);