зеркало из https://github.com/mozilla/gecko-dev.git
190 строки
9.1 KiB
C++
190 строки
9.1 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef MOZ_UNIT_TRANSFORMS_H_
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#define MOZ_UNIT_TRANSFORMS_H_
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#include "Units.h"
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#include "mozilla/gfx/Matrix.h"
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namespace mozilla {
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// Convenience functions for converting an entity from one strongly-typed
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// coordinate system to another without changing the values it stores (this
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// can be thought of as a cast).
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// To use these functions, you must provide a justification for each use!
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// Feel free to add more justifications to PixelCastJustification, along with
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// a comment that explains under what circumstances it is appropriate to use.
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enum class PixelCastJustification : uint8_t {
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// For the root layer, Screen Pixel = Parent Layer Pixel.
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ScreenIsParentLayerForRoot,
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// On the layout side, Screen Pixel = LayoutDevice at the outer-window level.
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LayoutDeviceIsScreenForBounds,
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// For the root layer, Render Target Pixel = Parent Layer Pixel.
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RenderTargetIsParentLayerForRoot,
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// For the root composition size we want to view it as layer pixels in any layer
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ParentLayerToLayerForRootComposition,
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// The Layer coordinate space for one layer is the ParentLayer coordinate
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// space for its children
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MovingDownToChildren,
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// The transform that is usually used to convert between two coordinate
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// systems is not available (for example, because the object that stores it
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// is being destroyed), so fall back to the identity.
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TransformNotAvailable,
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// When an OS event is initially constructed, its reference point is
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// technically in screen pixels, as it has not yet accounted for any
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// asynchronous transforms. This justification is for viewing the initial
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// reference point as a screen point.
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LayoutDeviceToScreenForUntransformedEvent,
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// Similar to LayoutDeviceToScreenForUntransformedEvent, PBrowser handles
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// some widget/tab dimension information as the OS does -- in screen units.
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LayoutDeviceIsScreenForTabDims
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};
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template <class TargetUnits, class SourceUnits>
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gfx::SizeTyped<TargetUnits> ViewAs(const gfx::SizeTyped<SourceUnits>& aSize, PixelCastJustification) {
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return gfx::SizeTyped<TargetUnits>(aSize.width, aSize.height);
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}
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template <class TargetUnits, class SourceUnits>
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gfx::IntSizeTyped<TargetUnits> ViewAs(const gfx::IntSizeTyped<SourceUnits>& aSize, PixelCastJustification) {
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return gfx::IntSizeTyped<TargetUnits>(aSize.width, aSize.height);
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}
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template <class TargetUnits, class SourceUnits>
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gfx::PointTyped<TargetUnits> ViewAs(const gfx::PointTyped<SourceUnits>& aPoint, PixelCastJustification) {
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return gfx::PointTyped<TargetUnits>(aPoint.x, aPoint.y);
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}
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template <class TargetUnits, class SourceUnits>
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gfx::IntPointTyped<TargetUnits> ViewAs(const gfx::IntPointTyped<SourceUnits>& aPoint, PixelCastJustification) {
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return gfx::IntPointTyped<TargetUnits>(aPoint.x, aPoint.y);
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}
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template <class TargetUnits, class SourceUnits>
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gfx::RectTyped<TargetUnits> ViewAs(const gfx::RectTyped<SourceUnits>& aRect, PixelCastJustification) {
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return gfx::RectTyped<TargetUnits>(aRect.x, aRect.y, aRect.width, aRect.height);
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}
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template <class TargetUnits, class SourceUnits>
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gfx::IntRectTyped<TargetUnits> ViewAs(const gfx::IntRectTyped<SourceUnits>& aRect, PixelCastJustification) {
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return gfx::IntRectTyped<TargetUnits>(aRect.x, aRect.y, aRect.width, aRect.height);
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}
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template <class NewTargetUnits, class OldTargetUnits, class SourceUnits>
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gfx::ScaleFactor<SourceUnits, NewTargetUnits> ViewTargetAs(
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const gfx::ScaleFactor<SourceUnits, OldTargetUnits>& aScaleFactor,
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PixelCastJustification) {
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return gfx::ScaleFactor<SourceUnits, NewTargetUnits>(aScaleFactor.scale);
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}
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// Convenience functions for casting untyped entities to typed entities.
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// Using these functions does not require a justification, but once we convert
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// all code to use strongly typed units they should not be needed any longer.
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template <class TargetUnits>
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gfx::PointTyped<TargetUnits> ViewAs(const gfxPoint& aPoint) {
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return gfx::PointTyped<TargetUnits>(aPoint.x, aPoint.y);
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}
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template <class TargetUnits>
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gfx::PointTyped<TargetUnits> ViewAs(const gfx::Point& aPoint) {
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return gfx::PointTyped<TargetUnits>(aPoint.x, aPoint.y);
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}
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template <class TargetUnits>
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gfx::RectTyped<TargetUnits> ViewAs(const gfx::Rect& aRect) {
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return gfx::RectTyped<TargetUnits>(aRect.x, aRect.y, aRect.width, aRect.height);
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}
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template <class TargetUnits>
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gfx::IntSizeTyped<TargetUnits> ViewAs(const nsIntSize& aSize) {
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return gfx::IntSizeTyped<TargetUnits>(aSize.width, aSize.height);
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}
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template <class TargetUnits>
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gfx::IntPointTyped<TargetUnits> ViewAs(const nsIntPoint& aPoint) {
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return gfx::IntPointTyped<TargetUnits>(aPoint.x, aPoint.y);
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}
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template <class TargetUnits>
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gfx::IntRectTyped<TargetUnits> ViewAs(const nsIntRect& aRect) {
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return gfx::IntRectTyped<TargetUnits>(aRect.x, aRect.y, aRect.width, aRect.height);
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}
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// Convenience functions for transforming an entity from one strongly-typed
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// coordinate system to another using the provided transformation matrix.
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template <typename TargetUnits, typename SourceUnits>
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static gfx::PointTyped<TargetUnits> TransformTo(const gfx::Matrix4x4& aTransform,
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const gfx::PointTyped<SourceUnits>& aPoint)
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{
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return ViewAs<TargetUnits>(aTransform * aPoint.ToUnknownPoint());
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}
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template <typename TargetUnits, typename SourceUnits>
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static gfx::IntPointTyped<TargetUnits> TransformTo(const gfx::Matrix4x4& aTransform,
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const gfx::IntPointTyped<SourceUnits>& aPoint)
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{
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return RoundedToInt(TransformTo<TargetUnits>(aTransform, gfx::PointTyped<SourceUnits>(aPoint)));
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}
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template <typename TargetUnits, typename SourceUnits>
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static gfx::RectTyped<TargetUnits> TransformTo(const gfx::Matrix4x4& aTransform,
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const gfx::RectTyped<SourceUnits>& aRect)
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{
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return ViewAs<TargetUnits>(aTransform.TransformBounds(aRect.ToUnknownRect()));
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}
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template <typename TargetUnits, typename SourceUnits>
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static gfx::IntRectTyped<TargetUnits> TransformTo(const gfx::Matrix4x4& aTransform,
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const gfx::IntRectTyped<SourceUnits>& aRect)
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{
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gfx::Rect rect(aRect.ToUnknownRect());
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return RoundedToInt(ViewAs<TargetUnits>(aTransform.TransformBounds(rect)));
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}
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// Transform |aVector|, which is anchored at |aAnchor|, by the given transform
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// matrix, yielding a point in |TargetUnits|.
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// The anchor is necessary because with 3D tranforms, the location of the
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// vector can affect the result of the transform.
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template <typename TargetUnits, typename SourceUnits>
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static gfx::PointTyped<TargetUnits> TransformVector(const gfx::Matrix4x4& aTransform,
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const gfx::PointTyped<SourceUnits>& aVector,
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const gfx::PointTyped<SourceUnits>& aAnchor) {
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gfx::PointTyped<TargetUnits> transformedStart = TransformTo<TargetUnits>(aTransform, aAnchor);
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gfx::PointTyped<TargetUnits> transformedEnd = TransformTo<TargetUnits>(aTransform, aAnchor + aVector);
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return transformedEnd - transformedStart;
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}
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// UntransformTo() and UntransformVector() are like TransformTo() and
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// TransformVector(), respectively, but are intended for cases where
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// the transformation matrix is the inverse of a 3D projection. When
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// using such transforms, the resulting Point4D is only meaningful
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// if it has a positive w-coordinate. To handle this, these functions
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// return a Maybe object which contains a value if and only if the
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// result is meaningful
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template <typename TargetUnits, typename SourceUnits>
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static Maybe<gfx::PointTyped<TargetUnits>> UntransformTo(const gfx::Matrix4x4& aTransform,
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const gfx::PointTyped<SourceUnits>& aPoint)
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{
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gfx::Point4D point = aTransform.ProjectPoint(aPoint.ToUnknownPoint());
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if (!point.HasPositiveWCoord()) {
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return Nothing();
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}
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return Some(ViewAs<TargetUnits>(point.As2DPoint()));
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}
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template <typename TargetUnits, typename SourceUnits>
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static Maybe<gfx::IntPointTyped<TargetUnits>> UntransformTo(const gfx::Matrix4x4& aTransform,
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const gfx::IntPointTyped<SourceUnits>& aPoint)
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{
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gfx::Point4D point = aTransform.ProjectPoint(aPoint.ToUnknownPoint());
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if (!point.HasPositiveWCoord()) {
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return Nothing();
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}
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return Some(RoundedToInt(ViewAs<TargetUnits>(point.As2DPoint())));
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}
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template <typename TargetUnits, typename SourceUnits>
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static Maybe<gfx::PointTyped<TargetUnits>> UntransformVector(const gfx::Matrix4x4& aTransform,
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const gfx::PointTyped<SourceUnits>& aVector,
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const gfx::PointTyped<SourceUnits>& aAnchor) {
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gfx::Point4D point = aTransform.ProjectPoint(aAnchor.ToUnknownPoint() + aVector.ToUnknownPoint())
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- aTransform.ProjectPoint(aAnchor.ToUnknownPoint());
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if (!point.HasPositiveWCoord()){
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return Nothing();
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}
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return Some(ViewAs<TargetUnits>(point.As2DPoint()));
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}
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} // namespace mozilla
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#endif
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