gecko-dev/image/DecoderFactory.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_image_DecoderFactory_h
#define mozilla_image_DecoderFactory_h
#include "DecoderFlags.h"
#include "mozilla/Attributes.h"
#include "mozilla/Maybe.h"
#include "mozilla/gfx/2D.h"
#include "nsCOMPtr.h"
#include "SurfaceFlags.h"
class nsACString;
namespace mozilla {
namespace image {
class Decoder;
class RasterImage;
class SourceBuffer;
/**
* The type of decoder; this is usually determined from a MIME type using
* DecoderFactory::GetDecoderType().
*/
enum class DecoderType
{
PNG,
GIF,
JPEG,
BMP,
ICO,
ICON,
UNKNOWN
};
class DecoderFactory
{
public:
/// @return the type of decoder which is appropriate for @aMimeType.
static DecoderType GetDecoderType(const char* aMimeType);
/**
* Creates and initializes a decoder for non-animated images of type @aType.
* (If the image *is* animated, only the first frame will be decoded.) The
* decoder will send notifications to @aImage.
*
* @param aType Which type of decoder to create - JPEG, PNG, etc.
* @param aImage The image will own the decoder and which should receive
* notifications as decoding progresses.
* @param aSourceBuffer The SourceBuffer which the decoder will read its data
* from.
* @param aTargetSize If not Nothing(), the target size which the image should
* be scaled to during decoding. It's an error to specify
* a target size for a decoder type which doesn't support
* downscale-during-decode.
* @param aDecoderFlags Flags specifying the behavior of this decoder.
* @param aSurfaceFlags Flags specifying the type of output this decoder
* should produce.
* @param aSampleSize The sample size requested using #-moz-samplesize (or 0
* if none).
*/
static already_AddRefed<Decoder>
CreateDecoder(DecoderType aType,
RasterImage* aImage,
SourceBuffer* aSourceBuffer,
const Maybe<gfx::IntSize>& aTargetSize,
DecoderFlags aDecoderFlags,
SurfaceFlags aSurfaceFlags,
int aSampleSize);
/**
* Creates and initializes a decoder for animated images of type @aType.
* The decoder will send notifications to @aImage.
*
* @param aType Which type of decoder to create - JPEG, PNG, etc.
* @param aImage The image will own the decoder and which should receive
* notifications as decoding progresses.
* @param aSourceBuffer The SourceBuffer which the decoder will read its data
* from.
* @param aDecoderFlags Flags specifying the behavior of this decoder.
* @param aSurfaceFlags Flags specifying the type of output this decoder
* should produce.
*/
static already_AddRefed<Decoder>
CreateAnimationDecoder(DecoderType aType,
RasterImage* aImage,
SourceBuffer* aSourceBuffer,
DecoderFlags aDecoderFlags,
SurfaceFlags aSurfaceFlags);
/**
* Creates and initializes a metadata decoder of type @aType. This decoder
* will only decode the image's header, extracting metadata like the size of
* the image. No actual image data will be decoded and no surfaces will be
* allocated. The decoder will send notifications to @aImage.
*
* @param aType Which type of decoder to create - JPEG, PNG, etc.
* @param aImage The image will own the decoder and which should receive
* notifications as decoding progresses.
* @param aSourceBuffer The SourceBuffer which the decoder will read its data
* from.
* @param aSampleSize The sample size requested using #-moz-samplesize (or 0
* if none).
*/
static already_AddRefed<Decoder>
CreateMetadataDecoder(DecoderType aType,
RasterImage* aImage,
SourceBuffer* aSourceBuffer,
int aSampleSize);
/**
* Creates and initializes an anonymous decoder (one which isn't associated
* with an Image object). Only the first frame of the image will be decoded.
*
* @param aType Which type of decoder to create - JPEG, PNG, etc.
* @param aSourceBuffer The SourceBuffer which the decoder will read its data
* from.
* @param aSurfaceFlags Flags specifying the type of output this decoder
* should produce.
*/
static already_AddRefed<Decoder>
CreateAnonymousDecoder(DecoderType aType,
SourceBuffer* aSourceBuffer,
SurfaceFlags aSurfaceFlags);
/**
* Creates and initializes an anonymous metadata decoder (one which isn't
* associated with an Image object). This decoder will only decode the image's
* header, extracting metadata like the size of the image. No actual image
* data will be decoded and no surfaces will be allocated.
*
* @param aType Which type of decoder to create - JPEG, PNG, etc.
* @param aSourceBuffer The SourceBuffer which the decoder will read its data
* from.
*/
static already_AddRefed<Decoder>
CreateAnonymousMetadataDecoder(DecoderType aType,
SourceBuffer* aSourceBuffer);
private:
virtual ~DecoderFactory() = 0;
/**
* An internal method which allocates a new decoder of the requested @aType.
*/
static already_AddRefed<Decoder> GetDecoder(DecoderType aType,
RasterImage* aImage,
bool aIsRedecode);
};
} // namespace image
} // namespace mozilla
#endif // mozilla_image_DecoderFactory_h