image/DecoderFactory.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   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_image_DecoderFactory_h
   8 #define mozilla_image_DecoderFactory_h
   9
  10 #include "DecoderFlags.h"
  11 #include "mozilla/Attributes.h"
  12 #include "mozilla/Maybe.h"
  13 #include "mozilla/gfx/2D.h"
  14 #include "nsCOMPtr.h"
  15 #include "SurfaceFlags.h"
  16
  17 class nsACString;
  18
  19 namespace mozilla {
  20 namespace image {
  21
  22 class Decoder;
  23 class RasterImage;
  24 class SourceBuffer;
  25
  26 /**
  27  * The type of decoder; this is usually determined from a MIME type using
  28  * DecoderFactory::GetDecoderType().
  29  */
  30 enum class DecoderType
  31 {
  32   PNG,
  33   GIF,
  34   JPEG,
  35   BMP,
  36   ICO,
  37   ICON,
  38   UNKNOWN
  39 };
  40
  41 class DecoderFactory
  42 {
  43 public:
  44   /// @return the type of decoder which is appropriate for @aMimeType.
  45   static DecoderType GetDecoderType(const char* aMimeType);
  46
  47   /**
  48    * Creates and initializes a decoder for non-animated images of type @aType.
  49    * (If the image *is* animated, only the first frame will be decoded.) The
  50    * decoder will send notifications to @aImage.
  51    *
  52    * @param aType Which type of decoder to create - JPEG, PNG, etc.
  53    * @param aImage The image will own the decoder and which should receive
  54    *               notifications as decoding progresses.
  55    * @param aSourceBuffer The SourceBuffer which the decoder will read its data
  56    *                      from.
  57    * @param aTargetSize If not Nothing(), the target size which the image should
  58    *                    be scaled to during decoding. It's an error to specify
  59    *                    a target size for a decoder type which doesn't support
  60    *                    downscale-during-decode.
  61    * @param aDecoderFlags Flags specifying the behavior of this decoder.
  62    * @param aSurfaceFlags Flags specifying the type of output this decoder
  63    *                      should produce.
  64    * @param aSampleSize The sample size requested using #-moz-samplesize (or 0
  65    *                    if none).
  66    */
  67   static already_AddRefed<Decoder>
  68   CreateDecoder(DecoderType aType,
  69                 RasterImage* aImage,
  70                 SourceBuffer* aSourceBuffer,
  71                 const Maybe<gfx::IntSize>& aTargetSize,
  72                 DecoderFlags aDecoderFlags,
  73                 SurfaceFlags aSurfaceFlags,
  74                 int aSampleSize);
  75
  76   /**
  77    * Creates and initializes a decoder for animated images of type @aType.
  78    * The decoder will send notifications to @aImage.
  79    *
  80    * @param aType Which type of decoder to create - JPEG, PNG, etc.
  81    * @param aImage The image will own the decoder and which should receive
  82    *               notifications as decoding progresses.
  83    * @param aSourceBuffer The SourceBuffer which the decoder will read its data
  84    *                      from.
  85    * @param aDecoderFlags Flags specifying the behavior of this decoder.
  86    * @param aSurfaceFlags Flags specifying the type of output this decoder
  87    *                      should produce.
  88    */
  89   static already_AddRefed<Decoder>
  90   CreateAnimationDecoder(DecoderType aType,
  91                          RasterImage* aImage,
  92                          SourceBuffer* aSourceBuffer,
  93                          DecoderFlags aDecoderFlags,
  94                          SurfaceFlags aSurfaceFlags);
  95
  96   /**
  97    * Creates and initializes a metadata decoder of type @aType. This decoder
  98    * will only decode the image's header, extracting metadata like the size of
  99    * the image. No actual image data will be decoded and no surfaces will be
 100    * allocated. The decoder will send notifications to @aImage.
 101    *
 102    * @param aType Which type of decoder to create - JPEG, PNG, etc.
 103    * @param aImage The image will own the decoder and which should receive
 104    *               notifications as decoding progresses.
 105    * @param aSourceBuffer The SourceBuffer which the decoder will read its data
 106    *                      from.
 107    * @param aSampleSize The sample size requested using #-moz-samplesize (or 0
 108    *                    if none).
 109    */
 110   static already_AddRefed<Decoder>
 111   CreateMetadataDecoder(DecoderType aType,
 112                         RasterImage* aImage,
 113                         SourceBuffer* aSourceBuffer,
 114                         int aSampleSize);
 115
 116   /**
 117    * Creates and initializes an anonymous decoder (one which isn't associated
 118    * with an Image object). Only the first frame of the image will be decoded.
 119    *
 120    * @param aType Which type of decoder to create - JPEG, PNG, etc.
 121    * @param aSourceBuffer The SourceBuffer which the decoder will read its data
 122    *                      from.
 123    * @param aSurfaceFlags Flags specifying the type of output this decoder
 124    *                      should produce.
 125    */
 126   static already_AddRefed<Decoder>
 127   CreateAnonymousDecoder(DecoderType aType,
 128                          SourceBuffer* aSourceBuffer,
 129                          SurfaceFlags aSurfaceFlags);
 130
 131   /**
 132    * Creates and initializes an anonymous metadata decoder (one which isn't
 133    * associated with an Image object). This decoder will only decode the image's
 134    * header, extracting metadata like the size of the image. No actual image
 135    * data will be decoded and no surfaces will be allocated.
 136    *
 137    * @param aType Which type of decoder to create - JPEG, PNG, etc.
 138    * @param aSourceBuffer The SourceBuffer which the decoder will read its data
 139    *                      from.
 140    */
 141   static already_AddRefed<Decoder>
 142   CreateAnonymousMetadataDecoder(DecoderType aType,
 143                                  SourceBuffer* aSourceBuffer);
 144
 145 private:
 146   virtual ~DecoderFactory() = 0;
 147
 148   /**
 149    * An internal method which allocates a new decoder of the requested @aType.
 150    */
 151   static already_AddRefed<Decoder> GetDecoder(DecoderType aType,
 152                                               RasterImage* aImage,
 153                                               bool aIsRedecode);
 154 };
 155
 156 } // namespace image
 157 } // namespace mozilla
 158
 159 #endif // mozilla_image_DecoderFactory_h