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/* -*- Mode: C++; tab-width: 2; 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/. */
/*
* A class representing three matrices that can be used for style transforms.
*/
#ifndef nsStyleTransformMatrix_h_
#define nsStyleTransformMatrix_h_
#include "mozilla/EnumeratedArray.h"
#include "nsCSSValue.h"
#include <limits>
class nsIFrame;
class nsStyleContext;
class nsPresContext;
struct gfxQuaternion;
struct nsRect;
namespace mozilla {
class RuleNodeCacheConditions;
} // namespace mozilla
/**
* A helper to generate gfxMatrixes from css transform functions.
*/
namespace nsStyleTransformMatrix {
// Function for applying perspective() transform function. We treat
// any value smaller than epsilon as perspective(infinity), which
// follows CSSWG's resolution on perspective(0). See bug 1316236.
inline void ApplyPerspectiveToMatrix(mozilla::gfx::Matrix4x4& aMatrix,
float aDepth)
{
if (aDepth >= std::numeric_limits<float>::epsilon()) {
aMatrix.Perspective(aDepth);
}
}
/**
* This class provides on-demand access to the 'reference box' for CSS
* transforms (needed to resolve percentage values in 'transform',
* 'transform-origin', etc.):
*
* http://dev.w3.org/csswg/css-transforms/#reference-box
*
* This class helps us to avoid calculating the reference box unless and
* until it is actually needed. This is important for performance when
* transforms are applied to SVG elements since the reference box for SVG is
* much more expensive to calculate (than for elements with a CSS layout box
* where we can use the nsIFrame's cached mRect), much more common (than on
* HTML), and yet very rarely have percentage values that require the
* reference box to be resolved. We also don't want to cause SVG frames to
* cache lots of ObjectBoundingBoxProperty objects that aren't needed.
*
* If UNIFIED_CONTINUATIONS (experimental, and currently broke) is defined,
* we consider the reference box for non-SVG frames to be the smallest
* rectangle containing a frame and all of its continuations. For example,
* if there is a <span> element with several continuations split over
* several lines, this function will return the rectangle containing all of
* those continuations. (This behavior is not currently in a spec.)
*/
class MOZ_STACK_CLASS TransformReferenceBox final {
public:
typedef nscoord (TransformReferenceBox::*DimensionGetter)();
explicit TransformReferenceBox()
: mFrame(nullptr)
, mIsCached(false)
{}
explicit TransformReferenceBox(const nsIFrame* aFrame)
: mFrame(aFrame)
, mIsCached(false)
{
MOZ_ASSERT(mFrame);
}
explicit TransformReferenceBox(const nsIFrame* aFrame,
const nsSize& aFallbackDimensions)
{
mFrame = aFrame;
mIsCached = false;
if (!mFrame) {
Init(aFallbackDimensions);
}
}
void Init(const nsIFrame* aFrame) {
MOZ_ASSERT(!mFrame && !mIsCached);
mFrame = aFrame;
}
void Init(const nsSize& aDimensions);
/**
* The offset of the reference box from the nsIFrame's TopLeft(). This
* is non-zero only in the case of SVG content. If we can successfully
* implement UNIFIED_CONTINUATIONS at some point in the future then it
* may also be non-zero for non-SVG content.
*/
nscoord X() {
EnsureDimensionsAreCached();
return mX;
}
nscoord Y() {
EnsureDimensionsAreCached();
return mY;
}
/**
* The size of the reference box.
*/
nscoord Width() {
EnsureDimensionsAreCached();
return mWidth;
}
nscoord Height() {
EnsureDimensionsAreCached();
return mHeight;
}
bool IsEmpty() {
return !mFrame;
}
private:
// We don't really need to prevent copying, but since none of our consumers
// currently need to copy, preventing copying may allow us to catch some
// cases where we use pass-by-value instead of pass-by-reference.
TransformReferenceBox(const TransformReferenceBox&) = delete;
void EnsureDimensionsAreCached();
const nsIFrame* mFrame;
nscoord mX, mY, mWidth, mHeight;
bool mIsCached;
};
/**
* Return the transform function, as an nsCSSKeyword, for the given
* nsCSSValue::Array from a transform list.
*/
nsCSSKeyword TransformFunctionOf(const nsCSSValue::Array* aData);
void SetIdentityMatrix(nsCSSValue::Array* aMatrix);
float ProcessTranslatePart(const nsCSSValue& aValue,
nsStyleContext* aContext,
nsPresContext* aPresContext,
mozilla::RuleNodeCacheConditions& aConditions,
TransformReferenceBox* aRefBox,
TransformReferenceBox::DimensionGetter aDimensionGetter = nullptr);
void
ProcessInterpolateMatrix(mozilla::gfx::Matrix4x4& aMatrix,
const nsCSSValue::Array* aData,
nsStyleContext* aContext,
nsPresContext* aPresContext,
mozilla::RuleNodeCacheConditions& aConditions,
TransformReferenceBox& aBounds,
bool* aContains3dTransform);
/**
* Given an nsCSSValueList containing -moz-transform functions,
* returns a matrix containing the value of those functions.
*
* @param aData The nsCSSValueList containing the transform functions
* @param aContext The style context, used for unit conversion.
* @param aPresContext The presentation context, used for unit conversion.
* @param aConditions Set to uncachable (by calling SetUncacheable()) if the
* result cannot be cached in the rule tree, otherwise untouched.
* @param aBounds The frame's bounding rectangle.
* @param aAppUnitsPerMatrixUnit The number of app units per device pixel.
* @param aContains3dTransform [out] Set to true if aList contains at least
* one 3d transform function (as defined in the CSS transforms
* specification), false otherwise.
*
* aContext and aPresContext may be null if all of the (non-percent)
* length values in aData are already known to have been converted to
* eCSSUnit_Pixel (as they are in an StyleAnimationValue)
*/
mozilla::gfx::Matrix4x4 ReadTransforms(const nsCSSValueList* aList,
nsStyleContext* aContext,
nsPresContext* aPresContext,
mozilla::RuleNodeCacheConditions& aConditions,
TransformReferenceBox& aBounds,
float aAppUnitsPerMatrixUnit,
bool* aContains3dTransform);
// Shear type for decomposition.
enum class ShearType {
XYSHEAR,
XZSHEAR,
YZSHEAR,
Count
};
using ShearArray =
mozilla::EnumeratedArray<ShearType, ShearType::Count, float>;
/*
* Implements the 2d transform matrix decomposition algorithm.
*/
bool Decompose2DMatrix(const mozilla::gfx::Matrix& aMatrix,
mozilla::gfx::Point3D& aScale,
ShearArray& aShear,
gfxQuaternion& aRotate,
mozilla::gfx::Point3D& aTranslate);
/*
* Implements the 3d transform matrix decomposition algorithm.
*/
bool Decompose3DMatrix(const mozilla::gfx::Matrix4x4& aMatrix,
mozilla::gfx::Point3D& aScale,
ShearArray& aShear,
gfxQuaternion& aRotate,
mozilla::gfx::Point3D& aTranslate,
mozilla::gfx::Point4D& aPerspective);
mozilla::gfx::Matrix CSSValueArrayTo2DMatrix(nsCSSValue::Array* aArray);
mozilla::gfx::Matrix4x4 CSSValueArrayTo3DMatrix(nsCSSValue::Array* aArray);
} // namespace nsStyleTransformMatrix
#endif
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