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 "mozilla/SVGImageContext.h"
  12 #include "mozilla/UniquePtr.h"
  13 #include "mozilla/dom/FromParser.h"
  14 #include "nsIContentInlines.h"
  15 #include "SVGAnimatedEnumeration.h"
  16 #include "SVGAnimatedLength.h"
  17 #include "SVGAnimatedPreserveAspectRatio.h"
  18 #include "SVGAnimatedViewBox.h"
  19 #include "SVGGraphicsElement.h"
  20 #include "SVGPoint.h"
  21 #include "SVGPreserveAspectRatio.h"
  22
  23 namespace mozilla {
  24 class AutoPreserveAspectRatioOverride;
  25 class SVGOuterSVGFrame;
  26 class SVGViewportFrame;
  27
  28 namespace dom {
  29 class DOMSVGAnimatedPreserveAspectRatio;
  30 class SVGAnimatedRect;
  31 class SVGViewElement;
  32 class SVGViewportElement;
  33
  34 class svgFloatSize {
  35  public:
  36   svgFloatSize(float aWidth, float aHeight) : width(aWidth), height(aHeight) {}
  37   bool operator!=(const svgFloatSize& rhs) {
  38     return width != rhs.width || height != rhs.height;
  39   }
  40   float width;
  41   float height;
  42 };
  43
  44 class SVGViewportElement : public SVGGraphicsElement {
  45   friend class mozilla::SVGOuterSVGFrame;
  46   friend class mozilla::SVGViewportFrame;
  47
  48  protected:
  49   explicit SVGViewportElement(
  50       already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
  51   ~SVGViewportElement() = default;
  52
  53  public:
  54   // nsIContent interface
  55   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
  56
  57   // SVGElement specializations:
  58   gfxMatrix PrependLocalTransformsTo(
  59       const gfxMatrix& aMatrix,
  60       SVGTransformTypes aWhich = eAllTransforms) const override;
  61
  62   bool HasValidDimensions() const override;
  63
  64   // SVGViewportElement methods:
  65
  66   float GetLength(uint8_t aCtxType) const;
  67
  68   // public helpers:
  69
  70   /**
  71    * Returns true if this element has a base/anim value for its "viewBox"
  72    * attribute that defines a viewBox rectangle with finite values, or
  73    * if there is a view element overriding this element's viewBox and it
  74    * has a valid viewBox.
  75    *
  76    * Note that this does not check whether we need to synthesize a viewBox,
  77    * so you must call ShouldSynthesizeViewBox() if you need to chck that too.
  78    *
  79    * Note also that this method does not pay attention to whether the width or
  80    * height values of the viewBox rect are positive!
  81    */
  82   bool HasViewBox() const { return GetViewBoxInternal().HasRect(); }
  83
  84   /**
  85    * Returns true if we should synthesize a viewBox for ourselves (that is, if
  86    * we're the root element in an image document, and we're not currently being
  87    * painted for an <svg:image> element).
  88    *
  89    * Only call this method if HasViewBox() returns false.
  90    */
  91   bool ShouldSynthesizeViewBox() const;
  92
  93   bool HasViewBoxOrSyntheticViewBox() const {
  94     return HasViewBox() || ShouldSynthesizeViewBox();
  95   }
  96
  97   bool HasChildrenOnlyTransform() const { return mHasChildrenOnlyTransform; }
  98
  99   void UpdateHasChildrenOnlyTransform();
 100
 101   enum ChildrenOnlyTransformChangedFlags { eDuringReflow = 1 };
 102
 103   /**
 104    * This method notifies the style system that the overflow rects of our
 105    * immediate childrens' frames need to be updated. It is called by our own
 106    * frame when changes (e.g. to currentScale) cause our children-only
 107    * transform to change.
 108    *
 109    * The reason we have this method instead of overriding
 110    * GetAttributeChangeHint is because we need to act on non-attribute (e.g.
 111    * currentScale) changes in addition to attribute (e.g. viewBox) changes.
 112    */
 113   void ChildrenOnlyTransformChanged(uint32_t aFlags = 0);
 114
 115   gfx::Matrix GetViewBoxTransform() const;
 116
 117   svgFloatSize GetViewportSize() const {
 118     return svgFloatSize(mViewportWidth, mViewportHeight);
 119   }
 120
 121   void SetViewportSize(const svgFloatSize& aSize) {
 122     mViewportWidth = aSize.width;
 123     mViewportHeight = aSize.height;
 124   }
 125
 126   /**
 127    * Returns true if either this is an SVG <svg> element that is the child of
 128    * another non-foreignObject SVG element, or this is a SVG <symbol> element
 129    * that is the root of a use-element shadow tree.
 130    */
 131   bool IsInner() const {
 132     const nsIContent* parent = GetFlattenedTreeParent();
 133     return parent && parent->IsSVGElement() &&
 134            !parent->IsSVGElement(nsGkAtoms::foreignObject);
 135   }
 136
 137   // WebIDL
 138   already_AddRefed<SVGAnimatedRect> ViewBox();
 139   already_AddRefed<DOMSVGAnimatedPreserveAspectRatio> PreserveAspectRatio();
 140   SVGAnimatedViewBox* GetAnimatedViewBox() override;
 141
 142  protected:
 143   // implementation helpers:
 144
 145   bool IsRootSVGSVGElement() const {
 146     NS_ASSERTION((IsInUncomposedDoc() && !GetParent()) ==
 147                      (OwnerDoc()->GetRootElement() == this),
 148                  "Can't determine if we're root");
 149     return !GetParent() && IsInUncomposedDoc() && IsSVGElement(nsGkAtoms::svg);
 150   }
 151
 152   /**
 153    * Returns the explicit or default preserveAspectRatio, unless we're
 154    * synthesizing a viewBox, in which case it returns the "none" value.
 155    */
 156   virtual SVGPreserveAspectRatio GetPreserveAspectRatioWithOverride() const {
 157     return mPreserveAspectRatio.GetAnimValue();
 158   }
 159
 160   /**
 161    * Returns the explicit viewBox rect, if specified, or else a synthesized
 162    * viewBox, if appropriate, or else a viewBox matching the dimensions of the
 163    * SVG viewport.
 164    */
 165   SVGViewBox GetViewBoxWithSynthesis(float aViewportWidth,
 166                                      float aViewportHeight) const;
 167
 168   enum { ATTR_X, ATTR_Y, ATTR_WIDTH, ATTR_HEIGHT };
 169   SVGAnimatedLength mLengthAttributes[4];
 170   static LengthInfo sLengthInfo[4];
 171   LengthAttributesInfo GetLengthInfo() override;
 172
 173   SVGAnimatedPreserveAspectRatio* GetAnimatedPreserveAspectRatio() override;
 174
 175   virtual const SVGAnimatedViewBox& GetViewBoxInternal() const {
 176     return mViewBox;
 177   }
 178   virtual SVGAnimatedTransformList* GetTransformInternal() const {
 179     return mTransforms.get();
 180   }
 181   SVGAnimatedViewBox mViewBox;
 182   SVGAnimatedPreserveAspectRatio mPreserveAspectRatio;
 183
 184   // The size of the rectangular SVG viewport into which we render. This is
 185   // not (necessarily) the same as the content area. See:
 186   //
 187   //   http://www.w3.org/TR/SVG11/coords.html#ViewportSpace
 188   //
 189   // XXXjwatt Currently only used for outer <svg>, but maybe we could use -1 to
 190   // flag this as an inner <svg> to save the overhead of GetCtx calls?
 191   // XXXjwatt our frame should probably reset these when it's destroyed.
 192   float mViewportWidth, mViewportHeight;
 193
 194   bool mHasChildrenOnlyTransform;
 195 };
 196
 197 }  // namespace dom
 198
 199 }  // namespace mozilla
 200
 201 #endif  // DOM_SVG_SVGVIEWPORTELEMENT_H_