layout/svg/nsCSSFilterInstance.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef __NS_CSSFILTERINSTANCE_H__
   7 #define __NS_CSSFILTERINSTANCE_H__
   8
   9 #include "FilterSupport.h"
  10 #include "gfxMatrix.h"
  11 #include "gfxRect.h"
  12 #include "mozilla/gfx/Point.h"
  13 #include "mozilla/gfx/Types.h"
  14 #include "nsColor.h"
  15
  16 class nsIFrame;
  17 struct nsStyleFilter;
  18 template<class T> class nsTArray;
  19
  20 /**
  21  * This class helps nsFilterInstance build its filter graph. It turns a CSS
  22  * filter function (e.g. blur(3px)) from the style system into a
  23  * FilterPrimitiveDescription connected to the filter graph.
  24  */
  25 class nsCSSFilterInstance
  26 {
  27   typedef mozilla::gfx::Color Color;
  28   typedef mozilla::gfx::FilterPrimitiveDescription FilterPrimitiveDescription;
  29   typedef mozilla::gfx::IntPoint IntPoint;
  30   typedef mozilla::gfx::PrimitiveType PrimitiveType;
  31   typedef mozilla::gfx::Size Size;
  32
  33 public:
  34   /**
  35    * @param aFilter The CSS filter from the style system. This class stores
  36    *   aFilter by reference, so callers should avoid modifying or deleting
  37    *   aFilter during the lifetime of nsCSSFilterInstance.
  38    * @param mTargetBBoxInFilterSpace The frame of element being filtered, in
  39    *   filter space.
  40    * @param aFrameSpaceInCSSPxToFilterSpaceTransform The transformation from
  41    *   the filtered element's frame space in CSS pixels to filter space.
  42    */
  43   nsCSSFilterInstance(const nsStyleFilter& aFilter,
  44                       nsIFrame *aTargetFrame,
  45                       const nsIntRect& mTargetBBoxInFilterSpace,
  46                       const gfxMatrix& aFrameSpaceInCSSPxToFilterSpaceTransform);
  47
  48   /**
  49    * Creates at least one new FilterPrimitiveDescription based on the filter
  50    * from the style system. Appends the new FilterPrimitiveDescription(s) to the
  51    * aPrimitiveDescrs list.
  52    */
  53   nsresult BuildPrimitives(nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs);
  54
  55 private:
  56   /**
  57    * Returns a new FilterPrimitiveDescription with its basic properties set up.
  58    */
  59   FilterPrimitiveDescription CreatePrimitiveDescription(PrimitiveType aType,
  60                                                         const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs);
  61
  62   /**
  63    * Sets aDescr's attributes using the style info in mFilter.
  64    */
  65   nsresult SetAttributesForBlur(FilterPrimitiveDescription& aDescr);
  66   nsresult SetAttributesForBrightness(FilterPrimitiveDescription& aDescr);
  67   nsresult SetAttributesForContrast(FilterPrimitiveDescription& aDescr);
  68   nsresult SetAttributesForDropShadow(FilterPrimitiveDescription& aDescr);
  69   nsresult SetAttributesForGrayscale(FilterPrimitiveDescription& aDescr);
  70   nsresult SetAttributesForHueRotate(FilterPrimitiveDescription& aDescr);
  71   nsresult SetAttributesForInvert(FilterPrimitiveDescription& aDescr);
  72   nsresult SetAttributesForOpacity(FilterPrimitiveDescription& aDescr);
  73   nsresult SetAttributesForSaturate(FilterPrimitiveDescription& aDescr);
  74   nsresult SetAttributesForSepia(FilterPrimitiveDescription& aDescr);
  75
  76   /**
  77    * Returns the index of the last result in the aPrimitiveDescrs, which we'll
  78    * use as the input to this CSS filter.
  79    */
  80   int32_t GetLastResultIndex(const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs);
  81
  82   /**
  83    * Sets aDescr's filter region and primitive subregion to appropriate values
  84    * based on this CSS filter's input and its attributes. For example, a CSS
  85    * blur filter will have bounds equal to its input bounds, inflated by the
  86    * blur extents.
  87    */
  88   void SetBounds(FilterPrimitiveDescription& aDescr,
  89                  const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs);
  90
  91   /**
  92    * Converts an nscolor to a Color, suitable for use as a
  93    * FilterPrimitiveDescription attribute.
  94    */
  95   Color ToAttributeColor(nscolor aColor);
  96
  97   /**
  98    * Converts a blur radius in frame space to filter space.
  99    */
 100   Size BlurRadiusToFilterSpace(nscoord aRadiusInFrameSpace);
 101
 102   /**
 103    * Converts a point defined by a pair of nscoord x, y coordinates from frame
 104    * space to filter space.
 105    */
 106   IntPoint OffsetToFilterSpace(nscoord aXOffsetInFrameSpace,
 107                                nscoord aYOffsetInFrameSpace);
 108
 109   /**
 110    * The CSS filter originally from the style system.
 111    */
 112   const nsStyleFilter& mFilter;
 113
 114   /**
 115    * The frame for the element that is currently being filtered.
 116    */
 117   nsIFrame*               mTargetFrame;
 118
 119   /**
 120    * The bounding box of the element being filtered, in filter space. Used for
 121    * input bounds if this CSS filter is the first in the filter chain.
 122    */
 123   nsIntRect mTargetBBoxInFilterSpace;
 124
 125   /**
 126    * The transformation from the filtered element's frame space in CSS pixels to
 127    * filter space. Used to transform style values to filter space.
 128    */
 129   gfxMatrix mFrameSpaceInCSSPxToFilterSpaceTransform;
 130 };
 131
 132 #endif