tenfourfox/image/Deinterlacer.h

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2017-04-19 07:56:45 +00:00
/* -*- 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/. */
/**
* Deinterlacer is a utility class to allow Downscaler to work with interlaced
* images.
* Since Downscaler needs to receive rows in top-to-bottom or
* bottom-to-top order, it can't natively handle interlaced images, in which the
* rows arrive in an interleaved order. Deinterlacer solves this problem by
* acting as an intermediate buffer that records decoded rows. Unlike
* Downscaler, it allows the rows to be written in arbitrary order. After each
* pass, calling PropagatePassToDownscaler() will downscale every buffered row
* in a single operation. The rows remain in the buffer, so rows that were
* written in one pass will be included in subsequent passes.
*/
#ifndef mozilla_image_Deinterlacer_h
#define mozilla_image_Deinterlacer_h
#include "Downscaler.h"
namespace mozilla {
namespace image {
class Deinterlacer
{
public:
explicit Deinterlacer(const nsIntSize& aImageSize);
bool IsValid() { return !!mBuffer; }
uint8_t* RowBuffer(uint32_t aRow);
void PropagatePassToDownscaler(Downscaler& aDownscaler);
private:
uint32_t RowSize() const;
nsIntSize mImageSize;
UniquePtr<uint8_t[]> mBuffer;
};
} // namespace image
} // namespace mozilla
#endif // mozilla_image_Deinterlacer_h