dom/svg/SVGMotionSMILPathUtils.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 /* Helper class to help with generating anonymous path elements for
   8    <animateMotion> elements to use. */
   9
  10 #ifndef DOM_SVG_SVGMOTIONSMILPATHUTILS_H_
  11 #define DOM_SVG_SVGMOTIONSMILPATHUTILS_H_
  12
  13 #include "mozilla/Attributes.h"
  14 #include "mozilla/RefPtr.h"
  15 #include "mozilla/SMILParserUtils.h"
  16 #include "mozilla/gfx/2D.h"
  17 #include "gfxPlatform.h"
  18 #include "nsDebug.h"
  19 #include "nsStringFwd.h"
  20 #include "nsTArray.h"
  21
  22 namespace mozilla {
  23
  24 namespace dom {
  25 class SVGElement;
  26 }
  27
  28 class SVGMotionSMILPathUtils {
  29   using DrawTarget = mozilla::gfx::DrawTarget;
  30   using Path = mozilla::gfx::Path;
  31   using PathBuilder = mozilla::gfx::PathBuilder;
  32
  33  public:
  34   // Class to assist in generating a Path, based on
  35   // coordinates in the <animateMotion> from/by/to/values attributes.
  36   class PathGenerator {
  37    public:
  38     explicit PathGenerator(const dom::SVGElement* aSVGElement)
  39         : mSVGElement(aSVGElement), mHaveReceivedCommands(false) {
  40       RefPtr<DrawTarget> drawTarget =
  41           gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget();
  42       NS_ASSERTION(
  43           gfxPlatform::GetPlatform()->SupportsAzureContentForDrawTarget(
  44               drawTarget),
  45           "Should support Moz2D content drawing");
  46
  47       mPathBuilder = drawTarget->CreatePathBuilder();
  48     }
  49
  50     // Methods for adding various path commands to output path.
  51     // Note: aCoordPairStr is expected to be a whitespace and/or
  52     // comma-separated x,y coordinate-pair -- see description of
  53     // "the specified values for from, by, to, and values" at
  54     //    http://www.w3.org/TR/SVG11/animate.html#AnimateMotionElement
  55     void MoveToOrigin();
  56     bool MoveToAbsolute(const nsAString& aCoordPairStr);
  57     bool LineToAbsolute(const nsAString& aCoordPairStr,
  58                         double& aSegmentDistance);
  59     bool LineToRelative(const nsAString& aCoordPairStr,
  60                         double& aSegmentDistance);
  61
  62     // Accessor to let clients check if we've received any commands yet.
  63     inline bool HaveReceivedCommands() { return mHaveReceivedCommands; }
  64     // Accessor to get the finalized path
  65     already_AddRefed<Path> GetResultingPath();
  66
  67    protected:
  68     // Helper methods
  69     bool ParseCoordinatePair(const nsAString& aCoordPairStr, float& aXVal,
  70                              float& aYVal);
  71
  72     // Member data
  73     const dom::SVGElement* mSVGElement;  // context for converting to user units
  74     RefPtr<PathBuilder> mPathBuilder;
  75     bool mHaveReceivedCommands;
  76   };
  77
  78   // Class to assist in passing each subcomponent of a |values| attribute to
  79   // a PathGenerator, for generating a corresponding Path.
  80   class MOZ_STACK_CLASS MotionValueParser
  81       : public SMILParserUtils::GenericValueParser {
  82    public:
  83     MotionValueParser(PathGenerator* aPathGenerator,
  84                       FallibleTArray<double>* aPointDistances)
  85         : mPathGenerator(aPathGenerator),
  86           mPointDistances(aPointDistances),
  87           mDistanceSoFar(0.0) {
  88       MOZ_ASSERT(mPointDistances->IsEmpty(),
  89                  "expecting point distances array to start empty");
  90     }
  91
  92     // SMILParserUtils::GenericValueParser interface
  93     bool Parse(const nsAString& aValueStr) override;
  94
  95    protected:
  96     PathGenerator* mPathGenerator;
  97     FallibleTArray<double>* mPointDistances;
  98     double mDistanceSoFar;
  99   };
 100 };
 101
 102 }  // namespace mozilla
 103
 104 #endif  // DOM_SVG_SVGMOTIONSMILPATHUTILS_H_