gecko-dev/gfx/layers/LayersHelpers.cpp

61 строка
2.2 KiB
C++

/* -*- 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 "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