gecko-dev/layout/svg/nsSVGFilterInstance.h

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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/. */
#ifndef __NS_SVGFILTERINSTANCE_H__
#define __NS_SVGFILTERINSTANCE_H__
#include "gfxMatrix.h"
#include "gfxRect.h"
#include "nsSVGFilters.h"
#include "nsSVGNumber2.h"
#include "nsSVGNumberPair.h"
#include "nsTArray.h"
class nsIFrame;
class nsSVGFilterFrame;
struct nsStyleFilter;
namespace mozilla {
namespace dom {
class SVGFilterElement;
}
}
/**
* This class helps nsFilterInstance build its filter graph by processing a
* single SVG reference filter.
*
* In BuildPrimitives, this class iterates through the referenced <filter>
* element's primitive elements, creating a FilterPrimitiveDescription for
* each one.
*
* This class uses several different coordinate spaces, defined as follows:
*
* "user space"
* The filtered SVG element's user space or the filtered HTML element's
* CSS pixel space. The origin for an HTML element is the top left corner of
* its border box.
*
* "filter space"
* User space scaled to device pixels. Shares the same origin as user space.
* This space is the same across chained SVG and CSS filters. To compute the
* overall filter space for a chain, we first need to build each filter's
* FilterPrimitiveDescriptions in some common space. That space is
* filter space.
*
* To understand the spaces better, let's take an example filter:
* <filter id="f">...</filter>
*
* And apply the filter to a div element:
* <div style="filter: url(#f); ...">...</div>
*
* And let's say there are 2 device pixels for every 1 CSS pixel.
*
* Finally, let's define an arbitrary point in user space:
* "user space point" = (10, 10)
*
* The point will be inset 10 CSS pixels from both the top and left edges of the
* div element's border box.
*
* Now, let's transform the point from user space to filter space:
* "filter space point" = "user space point" * "device pixels per CSS pixel"
* "filter space point" = (10, 10) * 2
* "filter space point" = (20, 20)
*/
class nsSVGFilterInstance
{
typedef mozilla::gfx::Point3D Point3D;
typedef mozilla::gfx::IntRect IntRect;
typedef mozilla::gfx::SourceSurface SourceSurface;
typedef mozilla::gfx::FilterPrimitiveDescription FilterPrimitiveDescription;
typedef mozilla::dom::UserSpaceMetrics UserSpaceMetrics;
public:
/**
* @param aFilter The SVG filter reference from the style system. This class
* stores aFilter by reference, so callers should avoid modifying or
* deleting aFilter during the lifetime of nsSVGFilterInstance.
* @param aTargetContent The filtered element.
* @param aTargetBBox The SVG bbox to use for the target frame, computed by
* the caller. The caller may decide to override the actual SVG bbox.
*/
nsSVGFilterInstance(const nsStyleFilter& aFilter,
nsIContent* aTargetContent,
const UserSpaceMetrics& aMetrics,
const gfxRect& aTargetBBox,
const gfxSize& aUserSpaceToFilterSpaceScale,
const gfxSize& aFilterSpaceToUserSpaceScale);
/**
* Returns true if the filter instance was created successfully.
*/
bool IsInitialized() const { return mInitialized; }
/**
* Iterates through the <filter> element's primitive elements, creating a
* FilterPrimitiveDescription for each one. Appends the new
* FilterPrimitiveDescription(s) to the aPrimitiveDescrs list. Also, appends
* new images from feImage filter primitive elements to the aInputImages list.
*/
nsresult BuildPrimitives(nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs,
nsTArray<mozilla::RefPtr<SourceSurface>>& aInputImages);
/**
* Returns the user specified "filter region", in the filtered element's user
* space, after it has been adjusted out (if necessary) so that its edges
* coincide with pixel boundaries of the offscreen surface into which the
* filtered output would/will be painted.
*/
gfxRect GetFilterRegion() const { return mUserSpaceBounds; }
/**
* Returns the size of the user specified "filter region", in filter space.
*/
nsIntRect GetFilterSpaceBounds() const { return mFilterSpaceBounds; }
float GetPrimitiveNumber(uint8_t aCtxType, const nsSVGNumber2 *aNumber) const
{
return GetPrimitiveNumber(aCtxType, aNumber->GetAnimValue());
}
float GetPrimitiveNumber(uint8_t aCtxType, const nsSVGNumberPair *aNumberPair,
nsSVGNumberPair::PairIndex aIndex) const
{
return GetPrimitiveNumber(aCtxType, aNumberPair->GetAnimValue(aIndex));
}
/**
* Converts a userSpaceOnUse/objectBoundingBoxUnits unitless point
* into filter space, depending on the value of mPrimitiveUnits. (For
* objectBoundingBoxUnits, the bounding box offset is applied to the point.)
*/
Point3D ConvertLocation(const Point3D& aPoint) const;
/**
* Transform a rect between user space and filter space.
*/
gfxRect UserSpaceToFilterSpace(const gfxRect& aUserSpaceRect) const;
private:
/**
* Finds the filter frame associated with this SVG filter.
*/
nsSVGFilterFrame* GetFilterFrame();
/**
* Computes the filter primitive subregion for the given primitive.
*/
IntRect ComputeFilterPrimitiveSubregion(nsSVGFE* aFilterElement,
const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs,
const nsTArray<int32_t>& aInputIndices);
/**
* Takes the input indices of a filter primitive and returns for each input
* whether the input's output is tainted.
*/
void GetInputsAreTainted(const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs,
const nsTArray<int32_t>& aInputIndices,
nsTArray<bool>& aOutInputsAreTainted);
/**
* Scales a numeric filter primitive length in the X, Y or "XY" directions
* into a length in filter space (no offset is applied).
*/
float GetPrimitiveNumber(uint8_t aCtxType, float aValue) const;
/**
* Transform a rect between user space and filter space.
*/
gfxRect FilterSpaceToUserSpace(const gfxRect& aFilterSpaceRect) const;
/**
* Returns the transform from frame space to the coordinate space that
* GetCanvasTM transforms to. "Frame space" is the origin of a frame, aka the
* top-left corner of its border box, aka the top left corner of its mRect.
*/
gfxMatrix GetUserSpaceToFrameSpaceInCSSPxTransform() const;
/**
* Appends a new FilterPrimitiveDescription to aPrimitiveDescrs that
* converts the FilterPrimitiveDescription at mSourceGraphicIndex into
* a SourceAlpha input for the next FilterPrimitiveDescription.
*
* The new FilterPrimitiveDescription zeros out the SourceGraphic's RGB
* channels and keeps the alpha channel intact.
*/
int32_t GetOrCreateSourceAlphaIndex(nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs);
/**
* Finds the index in aPrimitiveDescrs of each input to aPrimitiveElement.
* For example, if aPrimitiveElement is:
* <feGaussianBlur in="another-primitive" .../>
* Then, the resulting aSourceIndices will contain the index of the
* FilterPrimitiveDescription representing "another-primitive".
*/
nsresult GetSourceIndices(nsSVGFE* aPrimitiveElement,
nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs,
const nsDataHashtable<nsStringHashKey, int32_t>& aImageTable,
nsTArray<int32_t>& aSourceIndices);
/**
* Compute the filter region in user space, filter space, and filter
* space.
*/
nsresult ComputeBounds();
/**
* The SVG reference filter originally from the style system.
*/
const nsStyleFilter& mFilter;
/**
* The filtered element.
*/
nsIContent* mTargetContent;
/**
* The SVG user space metrics that SVG lengths are resolved against.
*/
const UserSpaceMetrics& mMetrics;
/**
* The filter element referenced by mTargetFrame's element.
*/
const mozilla::dom::SVGFilterElement* mFilterElement;
/**
* The frame for the SVG filter element.
*/
nsSVGFilterFrame* mFilterFrame;
/**
* The SVG bbox of the element that is being filtered, in user space.
*/
gfxRect mTargetBBox;
/**
* The "filter region" in various spaces.
*/
gfxRect mUserSpaceBounds;
nsIntRect mFilterSpaceBounds;
/**
* The scale factors between user space and filter space.
*/
gfxSize mUserSpaceToFilterSpaceScale;
gfxSize mFilterSpaceToUserSpaceScale;
/**
* The 'primitiveUnits' attribute value (objectBoundingBox or userSpaceOnUse).
*/
uint16_t mPrimitiveUnits;
/**
* The index of the FilterPrimitiveDescription that this SVG filter should use
* as its SourceGraphic, or the SourceGraphic keyword index if this is the
* first filter in a chain.
*/
int32_t mSourceGraphicIndex;
/**
* The index of the FilterPrimitiveDescription that this SVG filter should use
* as its SourceAlpha, or the SourceAlpha keyword index if this is the first
* filter in a chain.
*/
int32_t mSourceAlphaIndex;
/**
* SourceAlpha is available if GetOrCreateSourceAlphaIndex has been called.
*/
int32_t mSourceAlphaAvailable;
bool mInitialized;
};
#endif