gecko-dev/image/SurfacePipe.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */

#include "SurfacePipe.h"

#include <algorithm>  // for min

#include "Decoder.h"

namespace mozilla {
namespace image {

using namespace gfx;

using std::min;

Maybe<SurfaceInvalidRect> AbstractSurfaceSink::TakeInvalidRect() {
  if (mInvalidRect.IsEmpty()) {
    return Nothing();
  }

  SurfaceInvalidRect invalidRect;
  invalidRect.mInputSpaceRect = invalidRect.mOutputSpaceRect = mInvalidRect;

  // Forget about the invalid rect we're returning.
  mInvalidRect = IntRect();

  return Some(invalidRect);
}

uint8_t* AbstractSurfaceSink::DoResetToFirstRow() {
  mRow = 0;
  return GetRowPointer();
}

uint8_t* AbstractSurfaceSink::DoAdvanceRow() {
  if (mRow >= uint32_t(InputSize().height)) {
    return nullptr;
  }

  // If we're vertically flipping the output, we need to flip the invalid rect.
  // Since we're dealing with an axis-aligned rect, only the y coordinate needs
  // to change.
  int32_t invalidY = mFlipVertically ? InputSize().height - (mRow + 1) : mRow;
  mInvalidRect.UnionRect(mInvalidRect,
                         IntRect(0, invalidY, InputSize().width, 1));

  mRow = min(uint32_t(InputSize().height), mRow + 1);

  return mRow < uint32_t(InputSize().height) ? GetRowPointer() : nullptr;
}

nsresult SurfaceSink::Configure(const SurfaceConfig& aConfig) {
  IntSize surfaceSize = aConfig.mOutputSize;

  // Allocate the frame.
  // XXX(seth): Once every Decoder subclass uses SurfacePipe, we probably want
  // to allocate the frame directly here and get rid of Decoder::AllocateFrame
  // altogether.
  nsresult rv = aConfig.mDecoder->AllocateFrame(surfaceSize, aConfig.mFormat,
                                                aConfig.mAnimParams);
  if (NS_FAILED(rv)) {
    return rv;
  }

  mImageData = aConfig.mDecoder->mImageData;
  mImageDataLength = aConfig.mDecoder->mImageDataLength;
  mFlipVertically = aConfig.mFlipVertically;

  MOZ_ASSERT(mImageData);
  MOZ_ASSERT(uint64_t(mImageDataLength) == uint64_t(surfaceSize.width) *
                                               uint64_t(surfaceSize.height) *
                                               sizeof(uint32_t));

  ConfigureFilter(surfaceSize, sizeof(uint32_t));
  return NS_OK;
}

uint8_t* SurfaceSink::GetRowPointer() const {
  // If we're flipping vertically, reverse the order in which we traverse the
  // rows.
  uint32_t row = mFlipVertically ? InputSize().height - (mRow + 1) : mRow;

  uint8_t* rowPtr = mImageData + row * InputSize().width * sizeof(uint32_t);

  MOZ_ASSERT(rowPtr >= mImageData);
  MOZ_ASSERT(rowPtr < mImageData + mImageDataLength);
  MOZ_ASSERT(rowPtr + InputSize().width * sizeof(uint32_t) <=
             mImageData + mImageDataLength);

  return rowPtr;
}

}  // namespace image
}  // namespace mozilla