layout/svg/ISVGDisplayableFrame.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_ISVGDISPLAYABLEFRAME_H_
   8 #define LAYOUT_SVG_ISVGDISPLAYABLEFRAME_H_
   9
  10 #include "gfxMatrix.h"
  11 #include "gfxPoint.h"
  12 #include "gfxRect.h"
  13 #include "nsQueryFrame.h"
  14 #include "nsRect.h"
  15 #include "mozilla/gfx/MatrixFwd.h"
  16
  17 class gfxContext;
  18 class nsIFrame;
  19
  20 namespace mozilla {
  21 class SVGAnimatedLengthList;
  22 class SVGAnimatedNumberList;
  23 class SVGBBox;
  24 class SVGLengthList;
  25 class SVGNumberList;
  26 class SVGUserUnitList;
  27
  28 namespace image {
  29 struct imgDrawingParams;
  30 }  // namespace image
  31
  32 /**
  33  * This class is used for elements that can be part of a directly displayable
  34  * section of a document.  This includes SVGGeometryFrame and SVGGFrame.
  35  * (Even though the latter doesn't display anything itself, if it contains
  36  * SVGGeometryFrame descendants it is can still be part of a displayable
  37  * section of a document)  This class is not used for elements that can never
  38  * display directly, including SVGGradientFrame and SVGPatternFrame.  (The
  39  * latter may contain displayable content, but it and its content are never
  40  * *directly* displayed in a document.  It can only end up being displayed by
  41  * means of a reference from other content.)
  42  *
  43  * Note specifically that SVG frames that inherit SVGContainerFrame do *not*
  44  * implement this class (only those that inherit SVGDisplayContainerFrame
  45  * do.)
  46  */
  47 class ISVGDisplayableFrame : public nsQueryFrame {
  48  public:
  49   using imgDrawingParams = image::imgDrawingParams;
  50
  51   NS_DECL_QUERYFRAME_TARGET(ISVGDisplayableFrame)
  52
  53   /**
  54    * Paint this frame.
  55    *
  56    * SVG is painted using a combination of display lists (trees of
  57    * nsDisplayItem built by BuildDisplayList() implementations) and recursive
  58    * PaintSVG calls.  SVG frames with the NS_FRAME_IS_NONDISPLAY bit set are
  59    * always painted using recursive PaintSVG calls since display list painting
  60    * would provide no advantages (they wouldn't be retained for invalidation).
  61    * Displayed SVG is normally painted via a display list tree created under
  62    * SVGOuterSVGFrame::BuildDisplayList, In future we may use a PaintSVG() call
  63    * that recurses over the entire SVG frame tree on SVG container frames to
  64    * avoid display list construction when it is expensive and unnecessary (see
  65    * bug 934411).
  66    *
  67    * @param aTransform The transform that has to be multiplied onto the
  68    *   DrawTarget in order for drawing to be in this frame's SVG user space.
  69    *   Implementations of this method should avoid multiplying aTransform onto
  70    *   the DrawTarget when possible and instead just pass a transform down to
  71    *   their children.  This is preferable because changing the transform is
  72    *   very expensive for certain DrawTarget backends so it is best to minimize
  73    *   the number of transform changes.
  74    *
  75    * @param aImgParams imagelib parameters that may be used when painting
  76    *   feImage.
  77    */
  78   virtual void PaintSVG(gfxContext& aContext, const gfxMatrix& aTransform,
  79                         imgDrawingParams& aImgParams) = 0;
  80
  81   /**
  82    * Returns the frame that should handle pointer events at aPoint.  aPoint is
  83    * expected to be in the SVG user space of the frame on which this method is
  84    * called.  The frame returned may be the frame on which this method is
  85    * called, any of its descendants or else nullptr.
  86    */
  87   virtual nsIFrame* GetFrameForPoint(const gfxPoint& aPoint) = 0;
  88
  89   // Called on SVG child frames (except NS_FRAME_IS_NONDISPLAY frames)
  90   // to update and then invalidate their cached bounds. This method is not
  91   // called until after the SVGOuterSVGFrame has had its initial reflow
  92   // (i.e. once the SVG viewport dimensions are known). It should also only
  93   // be called by SVGOuterSVGFrame during its reflow.
  94   virtual void ReflowSVG() = 0;
  95
  96   // Flags to pass to NotifySVGChange:
  97   //
  98   // TRANSFORM_CHANGED:
  99   //   the current transform matrix for this frame has changed
 100   // COORD_CONTEXT_CHANGED:
 101   //   the dimensions of this frame's coordinate context has changed (percentage
 102   //   lengths must be reevaluated)
 103   // FULL_ZOOM_CHANGED:
 104   //   the page's zoom level has changed
 105   enum SVGChangedFlags {
 106     TRANSFORM_CHANGED = 0x01,
 107     COORD_CONTEXT_CHANGED = 0x02,
 108     FULL_ZOOM_CHANGED = 0x04
 109   };
 110   /**
 111    * This is called on a frame when there has been a change to one of its
 112    * ancestors that might affect the frame too. SVGChangedFlags are passed
 113    * to indicate what changed.
 114    *
 115    * Implementations do not need to invalidate, since the caller will
 116    * invalidate the entire area of the ancestor that changed. However, they
 117    * may need to update their bounds.
 118    */
 119   virtual void NotifySVGChanged(uint32_t aFlags) = 0;
 120
 121   /**
 122    * Get this frame's contribution to the rect returned by a GetBBox() call
 123    * that occurred either on this element, or on one of its ancestors.
 124    *
 125    * SVG defines an element's bbox to be the element's fill bounds in the
 126    * userspace established by that element. By allowing callers to pass in the
 127    * transform from the userspace established by this element to the userspace
 128    * established by an an ancestor, this method allows callers to obtain this
 129    * element's fill bounds in the userspace established by that ancestor
 130    * instead. In that case, since we return the bounds in a different userspace
 131    * (the ancestor's), the bounds we return are not this element's bbox, but
 132    * rather this element's contribution to the bbox of the ancestor.
 133    *
 134    * @param aToBBoxUserspace The transform from the userspace established by
 135    *   this element to the userspace established by the ancestor on which
 136    *   getBBox was called. This will be the identity matrix if we are the
 137    *   element on which getBBox was called.
 138    *
 139    * @param aFlags Flags indicating whether, stroke, for example, should be
 140    *   included in the bbox calculation.
 141    */
 142   virtual SVGBBox GetBBoxContribution(const gfx::Matrix& aToBBoxUserspace,
 143                                       uint32_t aFlags) = 0;
 144
 145   // Are we a container frame?
 146   virtual bool IsDisplayContainer() = 0;
 147 };
 148
 149 }  // namespace mozilla
 150
 151 #endif  // LAYOUT_SVG_ISVGDISPLAYABLEFRAME_H_