dom/svg/SVGPathData.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_SVGPATHDATA_H_
   8 #define DOM_SVG_SVGPATHDATA_H_
   9
  10 #include "nsCOMPtr.h"
  11 #include "nsDebug.h"
  12 #include "nsIContent.h"
  13 #include "nsINode.h"
  14 #include "nsIWeakReferenceUtils.h"
  15 #include "mozilla/dom/SVGElement.h"
  16 #include "mozilla/gfx/2D.h"
  17 #include "mozilla/gfx/Types.h"
  18 #include "mozilla/MemoryReporting.h"
  19 #include "mozilla/RefPtr.h"
  20 #include "mozilla/ServoStyleConsts.h"
  21 #include "nsTArray.h"
  22
  23 #include <string.h>
  24
  25 namespace mozilla {
  26
  27 struct SVGMark;
  28 enum class StyleStrokeLinecap : uint8_t;
  29
  30 class SVGPathData {
  31   friend class SVGAnimatedPathSegList;
  32   friend class SVGPathDataAndInfo;
  33   friend class SVGPathSegListSMILType;
  34
  35   using DrawTarget = gfx::DrawTarget;
  36   using Path = gfx::Path;
  37   using PathBuilder = gfx::PathBuilder;
  38   using FillRule = gfx::FillRule;
  39   using Float = gfx::Float;
  40   using CapStyle = gfx::CapStyle;
  41
  42  public:
  43   SVGPathData() = default;
  44   ~SVGPathData() = default;
  45
  46   explicit SVGPathData(const nsACString& aString) {
  47     SetValueFromString(aString);
  48   }
  49
  50   SVGPathData& operator=(const SVGPathData&) = default;
  51   SVGPathData(const SVGPathData&) = default;
  52   SVGPathData& operator=(SVGPathData&&) = default;
  53   SVGPathData(SVGPathData&&) = default;
  54
  55   // Used by SMILCompositor to check if the cached base val is out of date
  56   bool operator==(const SVGPathData& rhs) const { return mData == rhs.mData; }
  57
  58   // Only methods that don't make/permit modification to this list are public.
  59   // Only our friend classes can access methods that may change us.
  60
  61   /// This may return an incomplete string on OOM, but that's acceptable.
  62   void GetValueAsString(nsACString& aValue) const;
  63
  64   Span<const StylePathCommand> AsSpan() const { return mData._0.AsSpan(); }
  65   bool IsEmpty() const { return AsSpan().IsEmpty(); }
  66
  67   const StyleSVGPathData& RawData() const { return mData; }
  68
  69   void GetMarkerPositioningData(float aZoom, nsTArray<SVGMark>* aMarks) const;
  70
  71   static void GetMarkerPositioningData(Span<const StylePathCommand> aPath,
  72                                        float aZoom, nsTArray<SVGMark>* aMarks);
  73   /**
  74    * Returns true, except on OOM, in which case returns false.
  75    */
  76   bool GetDistancesFromOriginToEndsOfVisibleSegments(
  77       FallibleTArray<double>* aOutput) const;
  78
  79   /**
  80    * This is identical to the above one but accepts StylePathCommand.
  81    */
  82   static bool GetDistancesFromOriginToEndsOfVisibleSegments(
  83       Span<const StylePathCommand> aPath, FallibleTArray<double>* aOutput);
  84
  85   /**
  86    * This returns a path without the extra little line segments that
  87    * ApproximateZeroLengthSubpathSquareCaps can insert if we have square-caps.
  88    * See the comment for that function for more info on that.
  89    */
  90   already_AddRefed<Path> BuildPathForMeasuring(float aZoom) const;
  91
  92   already_AddRefed<Path> BuildPath(PathBuilder* aBuilder,
  93                                    StyleStrokeLinecap aStrokeLineCap,
  94                                    Float aStrokeWidth, float aZoom) const;
  95
  96   static already_AddRefed<Path> BuildPathForMeasuring(
  97       Span<const StylePathCommand> aPath, float aZoom);
  98
  99   /**
 100    * This function tries to build the path from an array of GenericShapeCommand,
 101    * which is generated by cbindgen from Rust (see ServoStyleConsts.h).
 102    * Basically, this is a variant of the above BuildPath() functions.
 103    * Note: |StylePathCommand| doesn't accept percentage values, so its |aBasis|
 104    * is empty by default.
 105    */
 106   static already_AddRefed<Path> BuildPath(Span<const StylePathCommand> aPath,
 107                                           PathBuilder* aBuilder,
 108                                           StyleStrokeLinecap aStrokeLineCap,
 109                                           Float aStrokeWidth,
 110                                           const CSSSize& aBasis = {},
 111                                           const gfx::Point& aOffset = {},
 112                                           float aZoomFactor = 1.0);
 113   static already_AddRefed<Path> BuildPath(
 114       Span<const StyleShapeCommand> aShape, PathBuilder* aBuilder,
 115       StyleStrokeLinecap aStrokeLineCap, Float aStrokeWidth,
 116       const CSSSize& aBasis, const gfx::Point& aOffset = gfx::Point(),
 117       float aZoomFactor = 1.0);
 118
 119   // memory reporting methods
 120   size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 121   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 122
 123  protected:
 124   nsresult SetValueFromString(const nsACString& aValue);
 125
 126   void Clear() { mData = {}; }
 127
 128   StyleSVGPathData& RawData() { return mData; }
 129
 130   mozilla::StyleSVGPathData mData;
 131 };
 132
 133 /**
 134  * This SVGPathData subclass is for SVGPathSegListSMILType which needs to
 135  * have write access to the lists it works with.
 136  *
 137  * Instances of this class do not have DOM wrappers that need to be kept in
 138  * sync, so we can safely expose any protected base class methods required by
 139  * the SMIL code.
 140  */
 141 class SVGPathDataAndInfo final : public SVGPathData {
 142  public:
 143   explicit SVGPathDataAndInfo(dom::SVGElement* aElement = nullptr)
 144       : mElement(do_GetWeakReference(static_cast<nsINode*>(aElement))) {}
 145
 146   void SetElement(dom::SVGElement* aElement) {
 147     mElement = do_GetWeakReference(static_cast<nsINode*>(aElement));
 148   }
 149
 150   dom::SVGElement* Element() const {
 151     nsCOMPtr<nsIContent> e = do_QueryReferent(mElement);
 152     return static_cast<dom::SVGElement*>(e.get());
 153   }
 154
 155   // If you use this, you need to call SetElement manually.
 156   void CopyFrom(const SVGPathData& aOther) { mData = aOther.mData; }
 157   void CopyFrom(const SVGPathDataAndInfo& aOther) {
 158     CopyFrom(static_cast<const SVGPathData&>(aOther));
 159     mElement = aOther.mElement;
 160   }
 161
 162   /**
 163    * Returns true if this object is an "identity" value, from the perspective
 164    * of SMIL. In other words, returns true until the initial value set up in
 165    * SVGPathSegListSMILType::Init() has been changed with a SetElement() call.
 166    */
 167   bool IsIdentity() const {
 168     if (!mElement) {
 169       MOZ_ASSERT(IsEmpty(), "target element propagation failure");
 170       return true;
 171     }
 172     return false;
 173   }
 174
 175  private:
 176   // We must keep a weak reference to our element because we may belong to a
 177   // cached baseVal SMILValue. See the comments starting at:
 178   // https://bugzilla.mozilla.org/show_bug.cgi?id=515116#c15
 179   // See also https://bugzilla.mozilla.org/show_bug.cgi?id=653497
 180   nsWeakPtr mElement;
 181 };
 182
 183 }  // namespace mozilla
 184
 185 #endif  // DOM_SVG_SVGPATHDATA_H_