dom/svg/SVGViewportElement.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 DOM_SVG_SVGVIEWPORTELEMENT_H_
   8 #define DOM_SVG_SVGVIEWPORTELEMENT_H_
   9
  10 #include "mozilla/Attributes.h"
  11 #include "nsIContentInlines.h"
  12 #include "SVGAnimatedEnumeration.h"
  13 #include "SVGAnimatedLength.h"
  14 #include "SVGAnimatedPreserveAspectRatio.h"
  15 #include "SVGAnimatedViewBox.h"
  16 #include "SVGGraphicsElement.h"
  17 #include "SVGPoint.h"
  18 #include "SVGPreserveAspectRatio.h"
  19
  20 namespace mozilla {
  21 class AutoPreserveAspectRatioOverride;
  22 class SVGOuterSVGFrame;
  23 class SVGViewportFrame;
  24
  25 namespace dom {
  26 class DOMSVGAnimatedPreserveAspectRatio;
  27 class SVGAnimatedRect;
  28 class SVGViewElement;
  29 class SVGViewportElement;
  30
  31 class SVGViewportElement : public SVGGraphicsElement {
  32   friend class mozilla::SVGOuterSVGFrame;
  33   friend class mozilla::SVGViewportFrame;
  34
  35  protected:
  36   explicit SVGViewportElement(
  37       already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
  38   ~SVGViewportElement() = default;
  39
  40  public:
  41   // nsIContent interface
  42   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
  43
  44   // SVGElement specializations:
  45   gfxMatrix ChildToUserSpaceTransform() const override;
  46
  47   bool HasValidDimensions() const override;
  48
  49   // SVGViewportElement methods:
  50
  51   float GetLength(uint8_t aCtxType) const;
  52
  53   // public helpers:
  54
  55   /**
  56    * Returns true if this element has a base/anim value for its "viewBox"
  57    * attribute that defines a viewBox rectangle with finite values, or
  58    * if there is a view element overriding this element's viewBox and it
  59    * has a valid viewBox.
  60    *
  61    * Note that this does not check whether we need to synthesize a viewBox,
  62    * so you must call ShouldSynthesizeViewBox() if you need to chck that too.
  63    *
  64    * Note also that this method does not pay attention to whether the width or
  65    * height values of the viewBox rect are positive!
  66    */
  67   bool HasViewBox() const { return GetViewBoxInternal().HasRect(); }
  68
  69   /**
  70    * Returns true if we should synthesize a viewBox for ourselves (that is, if
  71    * we're the root element in an image document, and we're not currently being
  72    * painted for an <svg:image> element).
  73    *
  74    * Only call this method if HasViewBox() returns false.
  75    */
  76   bool ShouldSynthesizeViewBox() const;
  77
  78   bool HasViewBoxOrSyntheticViewBox() const {
  79     return HasViewBox() || ShouldSynthesizeViewBox();
  80   }
  81
  82   bool HasChildrenOnlyTransform() const { return mHasChildrenOnlyTransform; }
  83
  84   void UpdateHasChildrenOnlyTransform();
  85
  86   enum ChildrenOnlyTransformChangedFlags { eDuringReflow = 1 };
  87
  88   /**
  89    * This method notifies the style system that the overflow rects of our
  90    * immediate childrens' frames need to be updated. It is called by our own
  91    * frame when changes (e.g. to currentScale) cause our children-only
  92    * transform to change.
  93    *
  94    * The reason we have this method instead of overriding
  95    * GetAttributeChangeHint is because we need to act on non-attribute (e.g.
  96    * currentScale) changes in addition to attribute (e.g. viewBox) changes.
  97    */
  98   void ChildrenOnlyTransformChanged(uint32_t aFlags = 0);
  99
 100   gfx::Matrix GetViewBoxTransform() const;
 101
 102   gfx::Size GetViewportSize() const { return mViewportSize; }
 103
 104   void SetViewportSize(const gfx::Size& aSize) { mViewportSize = aSize; }
 105
 106   /**
 107    * Returns true if either this is an SVG <svg> element that is the child of
 108    * another non-foreignObject SVG element, or this is a SVG <symbol> element
 109    * that is the root of a use-element shadow tree.
 110    */
 111   bool IsInner() const {
 112     const nsIContent* parent = GetFlattenedTreeParent();
 113     return parent && parent->IsSVGElement() &&
 114            !parent->IsSVGElement(nsGkAtoms::foreignObject);
 115   }
 116
 117   // WebIDL
 118   already_AddRefed<SVGAnimatedRect> ViewBox();
 119   already_AddRefed<DOMSVGAnimatedPreserveAspectRatio> PreserveAspectRatio();
 120   SVGAnimatedViewBox* GetAnimatedViewBox() override;
 121
 122  protected:
 123   // implementation helpers:
 124
 125   bool IsRootSVGSVGElement() const {
 126     NS_ASSERTION((IsInUncomposedDoc() && !GetParent()) ==
 127                      (OwnerDoc()->GetRootElement() == this),
 128                  "Can't determine if we're root");
 129     return !GetParent() && IsInUncomposedDoc() && IsSVGElement(nsGkAtoms::svg);
 130   }
 131
 132   /**
 133    * Returns the explicit or default preserveAspectRatio, unless we're
 134    * synthesizing a viewBox, in which case it returns the "none" value.
 135    */
 136   virtual SVGPreserveAspectRatio GetPreserveAspectRatioWithOverride() const {
 137     return mPreserveAspectRatio.GetAnimValue();
 138   }
 139
 140   /**
 141    * Returns the explicit viewBox rect, if specified, or else a synthesized
 142    * viewBox, if appropriate, or else a viewBox matching the dimensions of the
 143    * SVG viewport.
 144    */
 145   SVGViewBox GetViewBoxWithSynthesis(float aViewportWidth,
 146                                      float aViewportHeight) const;
 147
 148   enum { ATTR_X, ATTR_Y, ATTR_WIDTH, ATTR_HEIGHT };
 149   SVGAnimatedLength mLengthAttributes[4];
 150   static LengthInfo sLengthInfo[4];
 151   LengthAttributesInfo GetLengthInfo() override;
 152
 153   SVGAnimatedPreserveAspectRatio* GetAnimatedPreserveAspectRatio() override;
 154
 155   virtual const SVGAnimatedViewBox& GetViewBoxInternal() const {
 156     return mViewBox;
 157   }
 158   SVGAnimatedViewBox mViewBox;
 159   SVGAnimatedPreserveAspectRatio mPreserveAspectRatio;
 160
 161   // The size of the rectangular SVG viewport into which we render. This is
 162   // not (necessarily) the same as the content area. See:
 163   //
 164   //   http://www.w3.org/TR/SVG11/coords.html#ViewportSpace
 165   //
 166   // XXXjwatt Currently only used for outer <svg>, but maybe we could use -1 to
 167   // flag this as an inner <svg> to save the overhead of GetCtx calls?
 168   // XXXjwatt our frame should probably reset this when it's destroyed.
 169   gfx::Size mViewportSize;
 170
 171   bool mHasChildrenOnlyTransform;
 172 };
 173
 174 }  // namespace dom
 175
 176 }  // namespace mozilla
 177
 178 #endif  // DOM_SVG_SVGVIEWPORTELEMENT_H_