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 <cstdint>
  11
  12 #include "nsTArrayForwardDeclare.h"
  13
  14 namespace mozilla {
  15
  16 template <typename T>
  17 class Maybe;
  18
  19 namespace layers {
  20 class Image;
  21 }
  22
  23 class ErrorResult;
  24
  25 namespace dom {
  26
  27 struct ChannelPixelLayout;
  28 enum class ImageBitmapFormat : uint8_t;
  29
  30 typedef nsTArray<ChannelPixelLayout> ImagePixelLayout;
  31
  32 /*
  33  * ImageUtils is a wrapper around layers::Image. It provides three unified
  34  * methods to all sub-classes of layers::Image, which are:
  35  *
  36  * (1) GetFormat() converts the image's format into ImageBitmapFormat enum.
  37  * (2) GetBufferLength() returns the number of bytes that are used to store
  38  *     the image's underlying raw data.
  39  *
  40  * In theory, the functionalities of this class could be merged into the
  41  * interface of layers::Image. However, this is designed as a isolated wrapper
  42  * because we don't want to pollute the layers::Image's interface with methods
  43  * that are only meaningful to the ImageBitmap.
  44  */
  45 class ImageUtils {
  46  public:
  47   class Impl;
  48   ImageUtils() = delete;
  49   ImageUtils(const ImageUtils&) = delete;
  50   ImageUtils(ImageUtils&&) = delete;
  51   ImageUtils& operator=(const ImageUtils&) = delete;
  52   ImageUtils& operator=(ImageUtils&&) = delete;
  53
  54   explicit ImageUtils(layers::Image* aImage);
  55   ~ImageUtils();
  56
  57   Maybe<ImageBitmapFormat> GetFormat() const;
  58
  59   uint32_t GetBufferLength() const;
  60
  61  protected:
  62   Impl* mImpl;
  63 };
  64
  65 }  // namespace dom
  66 }  // namespace mozilla
  67
  68 #endif /* mozilla_dom_ImageBitmapFormatUtils_h */