gfx/layers/ImageLayers.cpp
author Robert O'Callahan <robert@ocallahan.org>
Fri, 07 Dec 2012 12:58:13 +1300
changeset 115340 55d5f3cd5c8514837024d5bc57ebc197429ff89c
parent 107428 e8382a09b0e5c02b36fc9744f89329d2da05da75
child 115349 df91b13737cf0e0cc24f691480f92ca120921a67
permissions -rw-r--r--
Bug 663776. Part 3: Refactor layer transform snapping to distinguish translation-snapping from rect-snapping, and don't snap translation+scale transforms when we don't know all four edges of the rect that needs to be snapped. r=mattwoodrow This separates SnapTransform into SnapTransformTranslation, which just snaps translations and nothing else, and SnapTransform, which snaps translation+scale of rectangles.

/* -*- Mode: C++; tab-width: 20; 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/. */

#include "ImageLayers.h"
#include "ImageContainer.h"

namespace mozilla {
namespace layers {

ImageLayer::ImageLayer(LayerManager* aManager, void* aImplData)
: Layer(aManager, aImplData), mFilter(gfxPattern::FILTER_GOOD)
, mScaleMode(SCALE_NONE), mForceSingleTile(false) 
{}

ImageLayer::~ImageLayer()
{}

void ImageLayer::SetContainer(ImageContainer* aContainer) 
{
  mContainer = aContainer;
}

void ImageLayer::ComputeEffectiveTransforms(const gfx3DMatrix& aTransformToSurface)
{
  gfx3DMatrix local = GetLocalTransform();

  // Snap image edges to pixel boundaries
  gfxRect sourceRect(0, 0, 0, 0);
  if (mContainer) {
    sourceRect.SizeTo(mContainer->GetCurrentSize());
    if (mScaleMode != SCALE_NONE &&
        sourceRect.width != 0.0 && sourceRect.height != 0.0) {
      NS_ASSERTION(mScaleMode == SCALE_STRETCH,
                   "No other scalemodes than stretch and none supported yet.");
      local.Scale(mScaleToSize.width / sourceRect.width,
                  mScaleToSize.height / sourceRect.height, 1.0);
    }
  }
  // Snap our local transform first, and snap the inherited transform as well.
  // This makes our snapping equivalent to what would happen if our content
  // was drawn into a ThebesLayer (gfxContext would snap using the local
  // transform, then we'd snap again when compositing the ThebesLayer).
  mEffectiveTransform =
      SnapTransform(local, sourceRect, nullptr) *
      SnapTransformTranslation(aTransformToSurface, nullptr);
  ComputeEffectiveTransformForMaskLayer(aTransformToSurface);
}

}
}