gecko-dev/gfx/layers/LayersHelpers.cpp

60 строки
2.0 KiB
C++

/* -*- 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 "LayersHelpers.h"
namespace mozilla {
namespace layers {
using namespace gfx;
gfx::IntRect
ComputeBackdropCopyRect(const gfx::Rect& aRect,
const gfx::IntRect& aClipRect,
const gfx::Matrix4x4& aTransform,
const gfx::IntRect& aRenderTargetRect,
gfx::Matrix4x4* aOutTransform,
gfx::Rect* aOutLayerQuad)
{
// Compute the clip.
IntPoint rtOffset = aRenderTargetRect.TopLeft();
IntSize rtSize = aRenderTargetRect.Size();
gfx::IntRect renderBounds(0, 0, rtSize.width, rtSize.height);
renderBounds.IntersectRect(renderBounds, aClipRect);
renderBounds.MoveBy(rtOffset);
// Apply the layer transform.
RectDouble dest = aTransform.TransformAndClipBounds(
RectDouble(aRect.x, aRect.y, aRect.Width(), aRect.Height()),
RectDouble(renderBounds.x, renderBounds.y, renderBounds.Width(), renderBounds.Height()));
dest -= rtOffset;
// Ensure we don't round out to -1, which trips up Direct3D.
dest.IntersectRect(dest, RectDouble(0, 0, rtSize.width, rtSize.height));
if (aOutLayerQuad) {
*aOutLayerQuad = Rect(dest.x, dest.y, dest.Width(), dest.Height());
}
// Round out to integer.
IntRect result;
dest.RoundOut();
dest.ToIntRect(&result);
// Create a transform from adjusted clip space to render target space,
// translate it for the backdrop rect, then transform it into the backdrop's
// uv-space.
Matrix4x4 transform;
transform.PostScale(rtSize.width, rtSize.height, 1.0);
transform.PostTranslate(-result.x, -result.y, 0.0);
transform.PostScale(1 / float(result.Width()), 1 / float(result.Height()), 1.0);
*aOutTransform = transform;
return result;
}
} // namespace layers
} // namespace mozilla