image/PlaybackType.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef mozilla_image_PlaybackType_h
   7 #define mozilla_image_PlaybackType_h
   8
   9 #include "imgIContainer.h"
  10
  11 namespace mozilla {
  12 namespace image {
  13
  14 /**
  15  * PlaybackType identifies a surface cache entry as either a static surface or
  16  * an animation. Note that a specific cache entry is one or the other, but
  17  * images may be associated with both types of cache entries, since in some
  18  * circumstances we may want to treat an animated image as if it were static.
  19  */
  20 enum class PlaybackType : uint8_t {
  21   eStatic,   // Calls to DrawableRef() will always return the same surface.
  22   eAnimated  // An animation; calls to DrawableRef() may return different
  23              // surfaces at different times.
  24 };
  25
  26 /**
  27  * Given an imgIContainer FRAME_* value, returns the corresponding PlaybackType
  28  * for use in surface cache lookups.
  29  */
  30 inline PlaybackType ToPlaybackType(uint32_t aWhichFrame) {
  31   MOZ_ASSERT(aWhichFrame == imgIContainer::FRAME_FIRST ||
  32              aWhichFrame == imgIContainer::FRAME_CURRENT);
  33   return aWhichFrame == imgIContainer::FRAME_CURRENT ? PlaybackType::eAnimated
  34                                                      : PlaybackType::eStatic;
  35 }
  36
  37 }  // namespace image
  38 }  // namespace mozilla
  39
  40 #endif  // mozilla_image_PlaybackType_h