layout/svg/CSSFilterInstance.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef LAYOUT_SVG_CSSFILTERINSTANCE_H_
   8 #define LAYOUT_SVG_CSSFILTERINSTANCE_H_
   9
  10 #include "FilterSupport.h"
  11 #include "gfxMatrix.h"
  12 #include "gfxRect.h"
  13 #include "mozilla/gfx/Point.h"
  14 #include "mozilla/gfx/Types.h"
  15 #include "nsColor.h"
  16 #include "mozilla/ServoStyleConsts.h"
  17
  18 namespace mozilla {
  19
  20 /**
  21  * This class helps FilterInstance 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 CSSFilterInstance {
  26   using sRGBColor = gfx::sRGBColor;
  27   using FilterPrimitiveDescription = gfx::FilterPrimitiveDescription;
  28   using IntPoint = gfx::IntPoint;
  29   using Size = gfx::Size;
  30
  31  public:
  32   /**
  33    * @param aFilter The CSS filter from the style system. This class stores
  34    *   aFilter by reference, so callers should avoid modifying or deleting
  35    *   aFilter during the lifetime of CSSFilterInstance.
  36    * @param aShadowFallbackColor The color that should be used for
  37    *   drop-shadow() filters that don't specify a shadow color.
  38    * @param aTargetBoundsInFilterSpace The pre-filter ink overflow rect of
  39    *   the frame being filtered, in filter space.
  40    * @param aFrameSpaceInCSSPxToFilterSpaceTransform The transformation from
  41    *   the filtered element's frame space in CSS pixels to filter space.
  42    */
  43   CSSFilterInstance(const StyleFilter& aFilter, nscolor aShadowFallbackColor,
  44                     const nsIntRect& aTargetBoundsInFilterSpace,
  45                     const gfxMatrix& aFrameSpaceInCSSPxToFilterSpaceTransform);
  46
  47   /**
  48    * Creates at least one new FilterPrimitiveDescription based on the filter
  49    * from the style system. Appends the new FilterPrimitiveDescription(s) to the
  50    * aPrimitiveDescrs list.
  51    * aInputIsTainted describes whether the input to this filter is tainted, i.e.
  52    * whether it contains security-sensitive content. This is needed to propagate
  53    * taintedness to the FilterPrimitive that take tainted inputs. Something
  54    * being tainted means that it contains security sensitive content. The input
  55    * to this filter is the previous filter's output, i.e. the last element in
  56    * aPrimitiveDescrs, or the SourceGraphic input if this is the first filter in
  57    * the filter chain.
  58    */
  59   nsresult BuildPrimitives(
  60       nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs,
  61       bool aInputIsTainted);
  62
  63  private:
  64   /**
  65    * Returns a new FilterPrimitiveDescription with its basic properties set up.
  66    * See the comment above BuildPrimitives for the meaning of aInputIsTainted.
  67    */
  68   FilterPrimitiveDescription CreatePrimitiveDescription(
  69       const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs,
  70       bool aInputIsTainted);
  71
  72   /**
  73    * Sets aDescr's attributes using the style info in mFilter.
  74    */
  75   nsresult SetAttributesForBlur(FilterPrimitiveDescription& aDescr);
  76   nsresult SetAttributesForBrightness(FilterPrimitiveDescription& aDescr);
  77   nsresult SetAttributesForContrast(FilterPrimitiveDescription& aDescr);
  78   nsresult SetAttributesForDropShadow(FilterPrimitiveDescription& aDescr);
  79   nsresult SetAttributesForGrayscale(FilterPrimitiveDescription& aDescr);
  80   nsresult SetAttributesForHueRotate(FilterPrimitiveDescription& aDescr);
  81   nsresult SetAttributesForInvert(FilterPrimitiveDescription& aDescr);
  82   nsresult SetAttributesForOpacity(FilterPrimitiveDescription& aDescr);
  83   nsresult SetAttributesForSaturate(FilterPrimitiveDescription& aDescr);
  84   nsresult SetAttributesForSepia(FilterPrimitiveDescription& aDescr);
  85
  86   /**
  87    * Returns the index of the last result in the aPrimitiveDescrs, which we'll
  88    * use as the input to this CSS filter.
  89    */
  90   int32_t GetLastResultIndex(
  91       const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs);
  92
  93   /**
  94    * Sets aDescr's filter region and primitive subregion to appropriate values
  95    * based on this CSS filter's input and its attributes. For example, a CSS
  96    * blur filter will have bounds equal to its input bounds, inflated by the
  97    * blur extents.
  98    */
  99   void SetBounds(FilterPrimitiveDescription& aDescr,
 100                  const nsTArray<FilterPrimitiveDescription>& aPrimitiveDescrs);
 101
 102   /**
 103    * Converts an nscolor to a Color, suitable for use as a
 104    * FilterPrimitiveDescription attribute.
 105    */
 106   sRGBColor ToAttributeColor(nscolor aColor);
 107
 108   /**
 109    * Converts a blur radius in frame space to filter space.
 110    */
 111   Size BlurRadiusToFilterSpace(nscoord aRadiusInFrameSpace);
 112
 113   /**
 114    * Converts a point defined by a pair of nscoord x, y coordinates from frame
 115    * space to filter space.
 116    */
 117   IntPoint OffsetToFilterSpace(nscoord aXOffsetInFrameSpace,
 118                                nscoord aYOffsetInFrameSpace);
 119
 120   /**
 121    * The CSS filter originally from the style system.
 122    */
 123   const StyleFilter& mFilter;
 124
 125   /**
 126    * The color that should be used for drop-shadow() filters that don't
 127    * specify a shadow color.
 128    */
 129   nscolor mShadowFallbackColor;
 130
 131   /**
 132    * The pre-filter overflow rect of the frame being filtered, in filter space.
 133    * Used for input bounds if this CSS filter is the first in the filter chain.
 134    */
 135   nsIntRect mTargetBoundsInFilterSpace;
 136
 137   /**
 138    * The transformation from the filtered element's frame space in CSS pixels to
 139    * filter space. Used to transform style values to filter space.
 140    */
 141   gfxMatrix mFrameSpaceInCSSPxToFilterSpaceTransform;
 142 };
 143
 144 }  // namespace mozilla
 145
 146 #endif  // LAYOUT_SVG_CSSFILTERINSTANCE_H_