dom/canvas/ImageUtils.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_ImageBitmapFormatUtils_h
   8 #define mozilla_dom_ImageBitmapFormatUtils_h
   9
  10 #include "mozilla/UniquePtr.h"
  11 #include "nsTArrayForwardDeclare.h"
  12
  13 namespace mozilla {
  14
  15 namespace layers {
  16 class Image;
  17 }
  18
  19 class ErrorResult;
  20
  21 namespace dom {
  22
  23 struct ChannelPixelLayout;
  24 enum class ImageBitmapFormat : uint8_t;
  25
  26 typedef nsTArray<ChannelPixelLayout> ImagePixelLayout;
  27
  28 /*
  29  * ImageUtils is a wrapper around layers::Image. It provides three unified
  30  * methods to all sub-classes of layers::Image, which are:
  31  *
  32  * (1) GetFormat() converts the image's format into ImageBitmapFormat enum.
  33  * (2) GetBufferLength() returns the number of bytes that are used to store
  34  *     the image's underlying raw data.
  35  *
  36  * In theory, the functionalities of this class could be merged into the
  37  * interface of layers::Image. However, this is designed as a isolated wrapper
  38  * because we don't want to pollute the layers::Image's interface with methods
  39  * that are only meaningful to the ImageBitmap.
  40  */
  41 class ImageUtils {
  42  public:
  43   class Impl;
  44   ImageUtils() = delete;
  45   ImageUtils(const ImageUtils&) = delete;
  46   ImageUtils(ImageUtils&&) = delete;
  47   ImageUtils& operator=(const ImageUtils&) = delete;
  48   ImageUtils& operator=(ImageUtils&&) = delete;
  49
  50   explicit ImageUtils(layers::Image* aImage);
  51   ~ImageUtils();
  52
  53   ImageBitmapFormat GetFormat() const;
  54
  55   uint32_t GetBufferLength() const;
  56
  57  protected:
  58   Impl* mImpl;
  59 };
  60
  61 }  // namespace dom
  62 }  // namespace mozilla
  63
  64 #endif /* mozilla_dom_ImageBitmapFormatUtils_h */