cc/contents_scaling_layer.cc

// Copyright 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/contents_scaling_layer.h"
#include "ui/gfx/size_conversions.h"

namespace cc {

gfx::Size ContentsScalingLayer::computeContentBoundsForScale(float scaleX, float scaleY) const {
  return gfx::ToCeiledSize(gfx::ScaleSize(bounds(), scaleX, scaleY));
}

ContentsScalingLayer::ContentsScalingLayer()
    : last_update_contents_scale_x_(0.f)
    , last_update_contents_scale_y_(0.f)
 {
}

ContentsScalingLayer::~ContentsScalingLayer() {
}

void ContentsScalingLayer::calculateContentsScale(
    float ideal_contents_scale,
    bool animating_transform_to_screen,
    float* contents_scale_x,
    float* contents_scale_y,
    gfx::Size* content_bounds) {
  *contents_scale_x = ideal_contents_scale;
  *contents_scale_y = ideal_contents_scale;
  *content_bounds = computeContentBoundsForScale(
      ideal_contents_scale,
      ideal_contents_scale);
}

void ContentsScalingLayer::didUpdateBounds() {
  drawProperties().content_bounds = computeContentBoundsForScale(
      contentsScaleX(),
      contentsScaleY());
}

void ContentsScalingLayer::update(
    ResourceUpdateQueue& queue,
    const OcclusionTracker* occlusion,
    RenderingStats* stats) {
  if (drawProperties().contents_scale_x == last_update_contents_scale_x_ &&
      drawProperties().contents_scale_y == last_update_contents_scale_y_)
    return;
  
  last_update_contents_scale_x_ = drawProperties().contents_scale_x;
  last_update_contents_scale_y_ = drawProperties().contents_scale_y;
  // Invalidate the whole layer if scale changed.
  setNeedsDisplayRect(gfx::Rect(bounds()));
}

}  // namespace cc