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- // Copyright 2017 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef CC_PAINT_IMAGE_ANIMATION_COUNT_H_
- #define CC_PAINT_IMAGE_ANIMATION_COUNT_H_
- namespace cc {
- // GIF and WebP support animation. The explanation below is in terms of GIF,
- // but the same constants are used for WebP, too.
- // GIFs have an optional 16-bit unsigned loop count that describes how an
- // animated GIF should be cycled. If the loop count is absent, the animation
- // cycles once; if it is 0, the animation cycles infinitely; otherwise the
- // animation plays n + 1 cycles (where n is the specified loop count). If the
- // GIF decoder defaults to kAnimationLoopOnce in the absence of any loop count
- // and translates an explicit "0" loop count to kAnimationLoopInfinite, then we
- // get a couple of nice side effects:
- // * By making kAnimationLoopOnce be 0, we allow the animation cycling code in
- // BitmapImage.cpp to avoid special-casing it, and simply treat all
- // non-negative loop counts identically.
- // * By making the other two constants negative, we avoid conflicts with any
- // real loop count values.
- const int kAnimationLoopOnce = 0;
- const int kAnimationLoopInfinite = -1;
- const int kAnimationNone = -2;
- } // namespace cc
- #endif // CC_PAINT_IMAGE_ANIMATION_COUNT_H_
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