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(nsIFrame* aFilteredFrame,
  93                                  Span<const StyleFilter> aFilterChain,
  94                                  gfxContext* aCtx,
  95                                  const SVGFilterPaintCallback& aPaintCallback,
  96                                  const nsRegion* aDirtyArea,
  97                                  imgDrawingParams& aImgParams,
  98                                  float aOpacity = 1.0f);
  99
 100   /**
 101    * Returns the post-filter area that could be dirtied when the given
 102    * pre-filter area of aFilteredFrame changes.
 103    * @param aPreFilterDirtyRegion The pre-filter area of aFilteredFrame that
 104    *   has changed, relative to aFilteredFrame, in app units.
 105    */
 106   static nsRegion GetPostFilterDirtyArea(nsIFrame* aFilteredFrame,
 107                                          const nsRegion& aPreFilterDirtyRegion);
 108
 109   /**
 110    * Returns the pre-filter area that is needed from aFilteredFrame when the
 111    * given post-filter area needs to be repainted.
 112    * @param aPostFilterDirtyRegion The post-filter area that is dirty, relative
 113    *   to aFilteredFrame, in app units.
 114    */
 115   static nsRegion GetPreFilterNeededArea(
 116       nsIFrame* aFilteredFrame, const nsRegion& aPostFilterDirtyRegion);
 117
 118   /**
 119    * Returns the post-filter ink overflow rect (paint bounds) of
 120    * aFilteredFrame.
 121    * @param aOverrideBBox A user space rect, in user units, that should be used
 122    *   as aFilteredFrame's bbox ('bbox' is a specific SVG term), if non-null.
 123    * @param aPreFilterBounds The pre-filter ink overflow rect of
 124    *   aFilteredFrame, if non-null.
 125    */
 126   static Maybe<nsRect> GetPostFilterBounds(
 127       nsIFrame* aFilteredFrame, const gfxRect* aOverrideBBox = nullptr,
 128       const nsRect* aPreFilterBounds = nullptr);
 129
 130   /**
 131    * Try to build WebRender filters for a frame if the filters applied to it are
 132    * supported. aInitialized is set to true if the filter has been initialized
 133    * and false otherwise (e.g. a bad url). If aInitialized is false the filter
 134    * the filter contents should not be drawn.
 135    */
 136   static bool BuildWebRenderFilters(
 137       nsIFrame* aFilteredFrame,
 138       mozilla::Span<const mozilla::StyleFilter> aFilters,
 139       WrFiltersHolder& aWrFilters, bool& aInitialized);
 140
 141  private:
 142   /**
 143    * @param aTargetFrame The frame of the filtered element under consideration,
 144    *   may be null.
 145    * @param aTargetContent The filtered element itself.
 146    * @param aMetrics The metrics to resolve SVG lengths against.
 147    * @param aFilterChain The list of filters to apply.
 148    * @param aFilterInputIsTainted Describes whether the SourceImage /
 149    *   SourceAlpha input is tainted. This affects whether feDisplacementMap
 150    *   will respect the filter input as its map input.
 151    * @param aPaintCallback [optional] The callback that Render() should use to
 152    *   paint. Only required if you will call Render().
 153    * @param aPaintTransform The transform to apply to convert to
 154    *   aTargetFrame's SVG user space. Only used when painting.
 155    * @param aPostFilterDirtyRegion [optional] The post-filter area
 156    *   that has to be repainted, in app units. Only required if you will
 157    *   call ComputeSourceNeededRect() or Render().
 158    * @param aPreFilterDirtyRegion [optional] The pre-filter area of
 159    *   the filtered element that changed, in app units. Only required if you
 160    *   will call ComputePostFilterDirtyRegion().
 161    * @param aPreFilterInkOverflowRectOverride [optional] Use a different
 162    *   ink overflow rect for the target element.
 163    * @param aOverrideBBox [optional] Use a different SVG bbox for the target
 164    *   element. Must be non-null if aTargetFrame is null.
 165    */
 166   FilterInstance(
 167       nsIFrame* aTargetFrame, nsIContent* aTargetContent,
 168       const UserSpaceMetrics& aMetrics, Span<const StyleFilter> aFilterChain,
 169       bool aFilterInputIsTainted,
 170       const SVGIntegrationUtils::SVGFilterPaintCallback& aPaintCallback,
 171       const gfxMatrix& aPaintTransform,
 172       const nsRegion* aPostFilterDirtyRegion = nullptr,
 173       const nsRegion* aPreFilterDirtyRegion = nullptr,
 174       const nsRect* aPreFilterInkOverflowRectOverride = nullptr,
 175       const gfxRect* aOverrideBBox = nullptr);
 176
 177   static bool BuildWebRenderFiltersImpl(
 178       nsIFrame* aFilteredFrame,
 179       mozilla::Span<const mozilla::StyleFilter> aFilters,
 180       WrFiltersHolder& aWrFilters, bool& aInitialized);
 181
 182   /**
 183    * Returns true if the filter instance was created successfully.
 184    */
 185   bool IsInitialized() const { return mInitialized; }
 186
 187   /**
 188    * Draws the filter output into aDrawTarget. The area that
 189    * needs to be painted must have been specified before calling this method
 190    * by passing it as the aPostFilterDirtyRegion argument to the
 191    * FilterInstance constructor.
 192    */
 193   void Render(gfxContext* aCtx, imgDrawingParams& aImgParams,
 194               float aOpacity = 1.0f);
 195
 196   const FilterDescription& ExtractDescriptionAndAdditionalImages(
 197       nsTArray<RefPtr<SourceSurface>>& aOutAdditionalImages) {
 198     aOutAdditionalImages = std::move(mInputImages);
 199     return mFilterDescription;
 200   }
 201
 202   /**
 203    * Sets the aPostFilterDirtyRegion outparam to the post-filter area in frame
 204    * space that would be dirtied by mTargetFrame when a given
 205    * pre-filter area of mTargetFrame is dirtied. The pre-filter area must have
 206    * been specified before calling this method by passing it as the
 207    * aPreFilterDirtyRegion argument to the FilterInstance constructor.
 208    */
 209   nsRegion ComputePostFilterDirtyRegion();
 210
 211   /**
 212    * Sets the aPostFilterExtents outparam to the post-filter bounds in frame
 213    * space for the whole filter output. This is not necessarily equivalent to
 214    * the area that would be dirtied in the result when the entire pre-filter
 215    * area is dirtied, because some filter primitives can generate output
 216    * without any input.
 217    */
 218   nsRect ComputePostFilterExtents();
 219
 220   /**
 221    * Sets the aDirty outparam to the pre-filter bounds in frame space of the
 222    * area of mTargetFrame that is needed in order to paint the filtered output
 223    * for a given post-filter dirtied area. The post-filter area must have been
 224    * specified before calling this method by passing it as the
 225    * aPostFilterDirtyRegion argument to the FilterInstance constructor.
 226    */
 227   nsRect ComputeSourceNeededRect();
 228
 229   struct SourceInfo {
 230     // Specifies which parts of the source need to be rendered.
 231     // Set by ComputeNeededBoxes().
 232     nsIntRect mNeededBounds;
 233
 234     // The surface that contains the input rendering.
 235     // Set by BuildSourceImage / BuildSourcePaint.
 236     RefPtr<SourceSurface> mSourceSurface;
 237
 238     // The position and size of mSourceSurface in filter space.
 239     // Set by BuildSourceImage / BuildSourcePaint.
 240     IntRect mSurfaceRect;
 241   };
 242
 243   /**
 244    * Creates a SourceSurface for either the FillPaint or StrokePaint graph
 245    * nodes
 246    */
 247   void BuildSourcePaint(SourceInfo* aSource, imgDrawingParams& aImgParams);
 248
 249   /**
 250    * Creates a SourceSurface for either the FillPaint and StrokePaint graph
 251    * nodes, fills its contents and assigns it to mFillPaint.mSourceSurface and
 252    * mStrokePaint.mSourceSurface respectively.
 253    */
 254   void BuildSourcePaints(imgDrawingParams& aImgParams);
 255
 256   /**
 257    * Creates the SourceSurface for the SourceGraphic graph node, paints its
 258    * contents, and assigns it to mSourceGraphic.mSourceSurface.
 259    */
 260   void BuildSourceImage(DrawTarget* aDest, imgDrawingParams& aImgParams,
 261                         mozilla::gfx::FilterNode* aFilter,
 262                         mozilla::gfx::FilterNode* aSource,
 263                         const mozilla::gfx::Rect& aSourceRect);
 264
 265   /**
 266    * Build the list of FilterPrimitiveDescriptions that describes the filter's
 267    * filter primitives and their connections. This populates
 268    * mPrimitiveDescriptions and mInputImages. aFilterInputIsTainted describes
 269    * whether the SourceGraphic is tainted.
 270    */
 271   nsresult BuildPrimitives(Span<const StyleFilter> aFilterChain,
 272                            nsIFrame* aTargetFrame, bool aFilterInputIsTainted);
 273
 274   /**
 275    * Add to the list of FilterPrimitiveDescriptions for a particular SVG
 276    * reference filter or CSS filter. This populates mPrimitiveDescriptions and
 277    * mInputImages. aInputIsTainted describes whether the input to aFilter is
 278    * tainted.
 279    */
 280   nsresult BuildPrimitivesForFilter(
 281       const StyleFilter& aFilter, nsIFrame* aTargetFrame, bool aInputIsTainted,
 282       nsTArray<FilterPrimitiveDescription>& aPrimitiveDescriptions);
 283
 284   /**
 285    * Computes the filter space bounds of the areas that we actually *need* from
 286    * the filter sources, based on the value of mPostFilterDirtyRegion.
 287    * This sets mNeededBounds on the corresponding SourceInfo structs.
 288    */
 289   void ComputeNeededBoxes();
 290
 291   /**
 292    * Returns the output bounds of the final FilterPrimitiveDescription.
 293    */
 294   nsIntRect OutputFilterSpaceBounds() const;
 295
 296   /**
 297    * Compute the scale factors between user space and filter space.
 298    */
 299   bool ComputeUserSpaceToFilterSpaceScale();
 300
 301   /**
 302    * Transform a rect between user space and filter space.
 303    */
 304   gfxRect UserSpaceToFilterSpace(const gfxRect& aUserSpace) const;
 305   gfxRect FilterSpaceToUserSpace(const gfxRect& aFilterSpaceRect) const;
 306
 307   /**
 308    * Converts an nsRect or an nsRegion that is relative to a filtered frame's
 309    * origin (i.e. the top-left corner of its border box) into filter space,
 310    * rounding out.
 311    * Returns the entire filter region if aRect / aRegion is null, or if the
 312    * result is too large to be stored in an nsIntRect.
 313    */
 314   nsIntRect FrameSpaceToFilterSpace(const nsRect* aRect) const;
 315   nsIntRegion FrameSpaceToFilterSpace(const nsRegion* aRegion) const;
 316
 317   /**
 318    * Converts an nsIntRect or an nsIntRegion from filter space into the space
 319    * that is relative to a filtered frame's origin (i.e. the top-left corner
 320    * of its border box) in app units, rounding out.
 321    */
 322   nsRect FilterSpaceToFrameSpace(const nsIntRect& aRect) const;
 323   nsRegion FilterSpaceToFrameSpace(const nsIntRegion& aRegion) const;
 324
 325   /**
 326    * Returns the transform from frame space to the coordinate space that
 327    * GetCanvasTM transforms to. "Frame space" is the origin of a frame, aka the
 328    * top-left corner of its border box, aka the top left corner of its mRect.
 329    */
 330   gfxMatrix GetUserSpaceToFrameSpaceInCSSPxTransform() const;
 331
 332   bool ComputeTargetBBoxInFilterSpace();
 333
 334   /**
 335    * The frame for the element that is currently being filtered.
 336    */
 337   nsIFrame* mTargetFrame;
 338
 339   /**
 340    * The filtered element.
 341    */
 342   nsIContent* mTargetContent;
 343
 344   /**
 345    * The user space metrics of the filtered frame.
 346    */
 347   const UserSpaceMetrics& mMetrics;
 348
 349   const SVGFilterPaintCallback& mPaintCallback;
 350
 351   /**
 352    * The SVG bbox of the element that is being filtered, in user space.
 353    */
 354   gfxRect mTargetBBox;
 355
 356   /**
 357    * The SVG bbox of the element that is being filtered, in filter space.
 358    */
 359   nsIntRect mTargetBBoxInFilterSpace;
 360
 361   /**
 362    * Transform rects between filter space and frame space in CSS pixels.
 363    */
 364   gfxMatrix mFilterSpaceToFrameSpaceInCSSPxTransform;
 365   gfxMatrix mFrameSpaceInCSSPxToFilterSpaceTransform;
 366
 367   /**
 368    * The scale factors between user space and filter space.
 369    */
 370   gfx::MatrixScalesDouble mUserSpaceToFilterSpaceScale;
 371   gfx::MatrixScalesDouble mFilterSpaceToUserSpaceScale;
 372
 373   /**
 374    * Pre-filter paint bounds of the element that is being filtered, in filter
 375    * space.
 376    */
 377   nsIntRect mTargetBounds;
 378
 379   /**
 380    * The dirty area that needs to be repainted, in filter space.
 381    */
 382   nsIntRegion mPostFilterDirtyRegion;
 383
 384   /**
 385    * The pre-filter area of the filtered element that changed, in filter space.
 386    */
 387   nsIntRegion mPreFilterDirtyRegion;
 388
 389   SourceInfo mSourceGraphic;
 390   SourceInfo mFillPaint;
 391   SourceInfo mStrokePaint;
 392
 393   /**
 394    * The transform to the SVG user space of mTargetFrame.
 395    */
 396   gfxMatrix mPaintTransform;
 397
 398   nsTArray<RefPtr<SourceSurface>> mInputImages;
 399   FilterDescription mFilterDescription;
 400   bool mInitialized;
 401 };
 402
 403 }  // namespace mozilla
 404
 405 #endif  // LAYOUT_SVG_FILTERINSTANCE_H_