layout/svg/FilterInstance.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_FILTERINSTANCE_H_
   8 #define LAYOUT_SVG_FILTERINSTANCE_H_
   9
  10 #include "gfxMatrix.h"
  11 #include "gfxPoint.h"
  12 #include "gfxRect.h"
  13 #include "nsCOMPtr.h"
  14 #include "FilterDescription.h"
  15 #include "nsHashKeys.h"
  16 #include "nsPoint.h"
  17 #include "nsRect.h"
  18 #include "nsSize.h"
  19 #include "nsTArray.h"
  20 #include "mozilla/gfx/2D.h"
  21 #include "mozilla/webrender/WebRenderTypes.h"
  22 #include "mozilla/ServoStyleConsts.h"
  23 #include "mozilla/SVGIntegrationUtils.h"
  24
  25 class gfxContext;
  26 class nsIContent;
  27 class nsIFrame;
  28 struct WrFiltersHolder;
  29
  30 namespace mozilla {
  31
  32 namespace dom {
  33 class UserSpaceMetrics;
  34 }  // namespace dom
  35
  36 namespace image {
  37 struct imgDrawingParams;
  38 }
  39
  40 /**
  41  * This class performs all filter processing.
  42  *
  43  * We build a graph of the filter image data flow, essentially
  44  * converting the filter graph to SSA. This lets us easily propagate
  45  * analysis data (such as bounding-boxes) over the filter primitive graph.
  46  *
  47  * Definition of "filter space": filter space is a coordinate system that is
  48  * aligned with the user space of the filtered element, with its origin located
  49  * at the top left of the filter region, and with one unit equal in size to one
  50  * pixel of the offscreen surface into which the filter output would/will be
  51  * painted.
  52  *
  53  * The definition of "filter region" can be found here:
  54  * http://www.w3.org/TR/SVG11/filters.html#FilterEffectsRegion
  55  */
  56 class FilterInstance {
  57   using IntRect = gfx::IntRect;
  58   using SourceSurface = gfx::SourceSurface;
  59   using DrawTarget = gfx::DrawTarget;
  60   using FilterPrimitiveDescription = gfx::FilterPrimitiveDescription;
  61   using FilterDescription = gfx::FilterDescription;
  62   using UserSpaceMetrics = dom::UserSpaceMetrics;
  63   using imgDrawingParams = image::imgDrawingParams;
  64   using SVGFilterPaintCallback = SVGIntegrationUtils::SVGFilterPaintCallback;
  65
  66  public:
  67   /**
  68    * Create a FilterDescription for the supplied filter. All coordinates in
  69    * the description are in filter space.
  70    * @param aFilterInputIsTainted Describes whether the SourceImage /
  71    *   SourceAlpha input is tainted. This affects whether feDisplacementMap
  72    *   will respect the filter input as its map input, and it affects the
  73    *   IsTainted() state on the filter primitives in the FilterDescription.
  74    *   "Tainted" is a term from the filters spec and means security-sensitive
  75    *   content, i.e. pixels that JS should not be able to read in any way.
  76    * @param aOutAdditionalImages Will contain additional images needed to
  77    *   render the filter (from feImage primitives).
  78    * @return A FilterDescription describing the filter.
  79    */
  80   static FilterDescription GetFilterDescription(
  81       nsIContent* aFilteredElement, Span<const StyleFilter> aFilterChain,
  82       bool aFilterInputIsTainted, const UserSpaceMetrics& aMetrics,
  83       const gfxRect& aBBox,
  84       nsTArray<RefPtr<SourceSurface>>& aOutAdditionalImages);
  85
  86   /**
  87    * Paint the given filtered frame.
  88    * @param aDirtyArea The area than needs to be painted, in aFilteredFrame's
  89    *   frame space (i.e. relative to its origin, the top-left corner of its
  90    *   border box).
  91    */
  92   static void PaintFilteredFrame(
  93       nsIFrame* aFilteredFrame, Span<const StyleFilter> aFilterChain,
  94       gfxContext* aCtx, const SVGFilterPaintCallback& aPaintCallback,
  95       const nsRegion* aDirtyArea, imgDrawingParams& aImgParams,
  96       float aOpacity = 1.0f, const gfxRect* aOverrideBBox = nullptr);
  97
  98   /**
  99    * Returns the post-filter area that could be dirtied when the given
 100    * pre-filter area of aFilteredFrame changes.
 101    * @param aPreFilterDirtyRegion The pre-filter area of aFilteredFrame that
 102    *   has changed, relative to aFilteredFrame, in app units.
 103    */
 104   static nsRegion GetPostFilterDirtyArea(nsIFrame* aFilteredFrame,
 105                                          const nsRegion& aPreFilterDirtyRegion);
 106
 107   /**
 108    * Returns the pre-filter area that is needed from aFilteredFrame when the
 109    * given post-filter area needs to be repainted.
 110    * @param aPostFilterDirtyRegion The post-filter area that is dirty, relative
 111    *   to aFilteredFrame, in app units.
 112    */
 113   static nsRegion GetPreFilterNeededArea(
 114       nsIFrame* aFilteredFrame, const nsRegion& aPostFilterDirtyRegion);
 115
 116   /**
 117    * Returns the post-filter ink overflow rect (paint bounds) of
 118    * aFilteredFrame.
 119    * @param aOverrideBBox A user space rect, in user units, that should be used
 120    *   as aFilteredFrame's bbox ('bbox' is a specific SVG term), if non-null.
 121    * @param aPreFilterBounds The pre-filter ink overflow rect of
 122    *   aFilteredFrame, if non-null.
 123    */
 124   static Maybe<nsRect> GetPostFilterBounds(
 125       nsIFrame* aFilteredFrame, const gfxRect* aOverrideBBox = nullptr,
 126       const nsRect* aPreFilterBounds = nullptr);
 127
 128   /**
 129    * Try to build WebRender filters for a frame if the filters applied to it are
 130    * supported. aInitialized is set to true if the filter has been initialized
 131    * and false otherwise (e.g. a bad url). If aInitialized is false the filter
 132    * the filter contents should not be drawn.
 133    */
 134   static bool BuildWebRenderFilters(
 135       nsIFrame* aFilteredFrame,
 136       mozilla::Span<const mozilla::StyleFilter> aFilters,
 137       WrFiltersHolder& aWrFilters, bool& aInitialized);
 138
 139  private:
 140   /**
 141    * @param aTargetFrame The frame of the filtered element under consideration,
 142    *   may be null.
 143    * @param aTargetContent The filtered element itself.
 144    * @param aMetrics The metrics to resolve SVG lengths against.
 145    * @param aFilterChain The list of filters to apply.
 146    * @param aFilterInputIsTainted Describes whether the SourceImage /
 147    *   SourceAlpha input is tainted. This affects whether feDisplacementMap
 148    *   will respect the filter input as its map input.
 149    * @param aPaintCallback [optional] The callback that Render() should use to
 150    *   paint. Only required if you will call Render().
 151    * @param aPaintTransform The transform to apply to convert to
 152    *   aTargetFrame's SVG user space. Only used when painting.
 153    * @param aPostFilterDirtyRegion [optional] The post-filter area
 154    *   that has to be repainted, in app units. Only required if you will
 155    *   call ComputeSourceNeededRect() or Render().
 156    * @param aPreFilterDirtyRegion [optional] The pre-filter area of
 157    *   the filtered element that changed, in app units. Only required if you
 158    *   will call ComputePostFilterDirtyRegion().
 159    * @param aPreFilterInkOverflowRectOverride [optional] Use a different
 160    *   ink overflow rect for the target element.
 161    * @param aOverrideBBox [optional] Use a different SVG bbox for the target
 162    *   element. Must be non-null if aTargetFrame is null.
 163    */
 164   FilterInstance(
 165       nsIFrame* aTargetFrame, nsIContent* aTargetContent,
 166       const UserSpaceMetrics& aMetrics, Span<const StyleFilter> aFilterChain,
 167       bool aFilterInputIsTainted,
 168       const SVGIntegrationUtils::SVGFilterPaintCallback& aPaintCallback,
 169       const gfxMatrix& aPaintTransform,
 170       const nsRegion* aPostFilterDirtyRegion = nullptr,
 171       const nsRegion* aPreFilterDirtyRegion = nullptr,
 172       const nsRect* aPreFilterInkOverflowRectOverride = nullptr,
 173       const gfxRect* aOverrideBBox = nullptr);
 174
 175   static bool BuildWebRenderFiltersImpl(
 176       nsIFrame* aFilteredFrame,
 177       mozilla::Span<const mozilla::StyleFilter> aFilters,
 178       WrFiltersHolder& aWrFilters, bool& aInitialized);
 179
 180   /**
 181    * Returns true if the filter instance was created successfully.
 182    */
 183   bool IsInitialized() const { return mInitialized; }
 184
 185   /**
 186    * Draws the filter output into aDrawTarget. The area that
 187    * needs to be painted must have been specified before calling this method
 188    * by passing it as the aPostFilterDirtyRegion argument to the
 189    * FilterInstance constructor.
 190    */
 191   void Render(gfxContext* aCtx, imgDrawingParams& aImgParams,
 192               float aOpacity = 1.0f);
 193
 194   const FilterDescription& ExtractDescriptionAndAdditionalImages(
 195       nsTArray<RefPtr<SourceSurface>>& aOutAdditionalImages) {
 196     aOutAdditionalImages = std::move(mInputImages);
 197     return mFilterDescription;
 198   }
 199
 200   /**
 201    * Sets the aPostFilterDirtyRegion outparam to the post-filter area in frame
 202    * space that would be dirtied by mTargetFrame when a given
 203    * pre-filter area of mTargetFrame is dirtied. The pre-filter area must have
 204    * been specified before calling this method by passing it as the
 205    * aPreFilterDirtyRegion argument to the FilterInstance constructor.
 206    */
 207   nsRegion ComputePostFilterDirtyRegion();
 208
 209   /**
 210    * Sets the aPostFilterExtents outparam to the post-filter bounds in frame
 211    * space for the whole filter output. This is not necessarily equivalent to
 212    * the area that would be dirtied in the result when the entire pre-filter
 213    * area is dirtied, because some filter primitives can generate output
 214    * without any input.
 215    */
 216   nsRect ComputePostFilterExtents();
 217
 218   /**
 219    * Sets the aDirty outparam to the pre-filter bounds in frame space of the
 220    * area of mTargetFrame that is needed in order to paint the filtered output
 221    * for a given post-filter dirtied area. The post-filter area must have been
 222    * specified before calling this method by passing it as the
 223    * aPostFilterDirtyRegion argument to the FilterInstance constructor.
 224    */
 225   nsRect ComputeSourceNeededRect();
 226
 227   struct SourceInfo {
 228     // Specifies which parts of the source need to be rendered.
 229     // Set by ComputeNeededBoxes().
 230     nsIntRect mNeededBounds;
 231
 232     // The surface that contains the input rendering.
 233     // Set by BuildSourceImage / BuildSourcePaint.
 234     RefPtr<SourceSurface> mSourceSurface;
 235
 236     // The position and size of mSourceSurface in filter space.
 237     // Set by BuildSourceImage / BuildSourcePaint.
 238     IntRect mSurfaceRect;
 239   };
 240
 241   /**
 242    * Creates a SourceSurface for either the FillPaint or StrokePaint graph
 243    * nodes
 244    */
 245   void BuildSourcePaint(SourceInfo* aSource, imgDrawingParams& aImgParams);
 246
 247   /**
 248    * Creates a SourceSurface for either the FillPaint and StrokePaint graph
 249    * nodes, fills its contents and assigns it to mFillPaint.mSourceSurface and
 250    * mStrokePaint.mSourceSurface respectively.
 251    */
 252   void BuildSourcePaints(imgDrawingParams& aImgParams);
 253
 254   /**
 255    * Creates the SourceSurface for the SourceGraphic graph node, paints its
 256    * contents, and assigns it to mSourceGraphic.mSourceSurface.
 257    */
 258   void BuildSourceImage(DrawTarget* aDest, imgDrawingParams& aImgParams,
 259                         mozilla::gfx::FilterNode* aFilter,
 260                         mozilla::gfx::FilterNode* aSource,
 261                         const mozilla::gfx::Rect& aSourceRect);
 262
 263   /**
 264    * Build the list of FilterPrimitiveDescriptions that describes the filter's
 265    * filter primitives and their connections. This populates
 266    * mPrimitiveDescriptions and mInputImages. aFilterInputIsTainted describes
 267    * whether the SourceGraphic is tainted.
 268    */
 269   nsresult BuildPrimitives(Span<const StyleFilter> aFilterChain,
 270                            nsIFrame* aTargetFrame, bool aFilterInputIsTainted);
 271
 272   /**
 273    * Add to the list of FilterPrimitiveDescriptions for a particular SVG
 274    * reference filter or CSS filter. This populates mPrimitiveDescriptions and
 275    * mInputImages. aInputIsTainted describes whether the input to aFilter is
 276    * tainted.
 277    */
 278   nsresult BuildPrimitivesForFilter(
 279       const StyleFilter& aFilter, nsIFrame* aTargetFrame, bool aInputIsTainted,
 280       nsTArray<FilterPrimitiveDescription>& aPrimitiveDescriptions);
 281
 282   /**
 283    * Computes the filter space bounds of the areas that we actually *need* from
 284    * the filter sources, based on the value of mPostFilterDirtyRegion.
 285    * This sets mNeededBounds on the corresponding SourceInfo structs.
 286    */
 287   void ComputeNeededBoxes();
 288
 289   /**
 290    * Returns the output bounds of the final FilterPrimitiveDescription.
 291    */
 292   nsIntRect OutputFilterSpaceBounds() const;
 293
 294   /**
 295    * Compute the scale factors between user space and filter space.
 296    */
 297   bool ComputeUserSpaceToFilterSpaceScale();
 298
 299   /**
 300    * Transform a rect between user space and filter space.
 301    */
 302   gfxRect UserSpaceToFilterSpace(const gfxRect& aUserSpace) const;
 303   gfxRect FilterSpaceToUserSpace(const gfxRect& aFilterSpaceRect) const;
 304
 305   /**
 306    * Converts an nsRect or an nsRegion that is relative to a filtered frame's
 307    * origin (i.e. the top-left corner of its border box) into filter space,
 308    * rounding out.
 309    * Returns the entire filter region if aRect / aRegion is null, or if the
 310    * result is too large to be stored in an nsIntRect.
 311    */
 312   nsIntRect FrameSpaceToFilterSpace(const nsRect* aRect) const;
 313   nsIntRegion FrameSpaceToFilterSpace(const nsRegion* aRegion) const;
 314
 315   /**
 316    * Converts an nsIntRect or an nsIntRegion from filter space into the space
 317    * that is relative to a filtered frame's origin (i.e. the top-left corner
 318    * of its border box) in app units, rounding out.
 319    */
 320   nsRect FilterSpaceToFrameSpace(const nsIntRect& aRect) const;
 321   nsRegion FilterSpaceToFrameSpace(const nsIntRegion& aRegion) const;
 322
 323   /**
 324    * Returns the transform from frame space to the coordinate space that
 325    * GetCanvasTM transforms to. "Frame space" is the origin of a frame, aka the
 326    * top-left corner of its border box, aka the top left corner of its mRect.
 327    */
 328   gfxMatrix GetUserSpaceToFrameSpaceInCSSPxTransform() const;
 329
 330   bool ComputeTargetBBoxInFilterSpace();
 331
 332   /**
 333    * The frame for the element that is currently being filtered.
 334    */
 335   nsIFrame* mTargetFrame;
 336
 337   /**
 338    * The filtered element.
 339    */
 340   nsIContent* mTargetContent;
 341
 342   /**
 343    * The user space metrics of the filtered frame.
 344    */
 345   const UserSpaceMetrics& mMetrics;
 346
 347   const SVGFilterPaintCallback& mPaintCallback;
 348
 349   /**
 350    * The SVG bbox of the element that is being filtered, in user space.
 351    */
 352   gfxRect mTargetBBox;
 353
 354   /**
 355    * The SVG bbox of the element that is being filtered, in filter space.
 356    */
 357   nsIntRect mTargetBBoxInFilterSpace;
 358
 359   /**
 360    * Transform rects between filter space and frame space in CSS pixels.
 361    */
 362   gfxMatrix mFilterSpaceToFrameSpaceInCSSPxTransform;
 363   gfxMatrix mFrameSpaceInCSSPxToFilterSpaceTransform;
 364
 365   /**
 366    * The scale factors between user space and filter space.
 367    */
 368   gfx::MatrixScalesDouble mUserSpaceToFilterSpaceScale;
 369   gfx::MatrixScalesDouble mFilterSpaceToUserSpaceScale;
 370
 371   /**
 372    * Pre-filter paint bounds of the element that is being filtered, in filter
 373    * space.
 374    */
 375   nsIntRect mTargetBounds;
 376
 377   /**
 378    * The dirty area that needs to be repainted, in filter space.
 379    */
 380   nsIntRegion mPostFilterDirtyRegion;
 381
 382   /**
 383    * The pre-filter area of the filtered element that changed, in filter space.
 384    */
 385   nsIntRegion mPreFilterDirtyRegion;
 386
 387   SourceInfo mSourceGraphic;
 388   SourceInfo mFillPaint;
 389   SourceInfo mStrokePaint;
 390
 391   /**
 392    * The transform to the SVG user space of mTargetFrame.
 393    */
 394   gfxMatrix mPaintTransform;
 395
 396   nsTArray<RefPtr<SourceSurface>> mInputImages;
 397   FilterDescription mFilterDescription;
 398   bool mInitialized;
 399 };
 400
 401 }  // namespace mozilla
 402
 403 #endif  // LAYOUT_SVG_FILTERINSTANCE_H_