gecko-dev/dom/svg/SVGAnimatedLength.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef DOM_SVG_SVGANIMATEDLENGTH_H_
#define DOM_SVG_SVGANIMATEDLENGTH_H_

#include "mozilla/Attributes.h"
#include "mozilla/SMILAttr.h"
#include "mozilla/SVGContentUtils.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/dom/SVGLengthBinding.h"
#include "mozilla/dom/SVGElement.h"
#include "nsError.h"

struct GeckoFontMetrics;
class nsPresContext;
class nsFontMetrics;
class mozAutoDocUpdate;
class nsIFrame;

namespace mozilla {

class AutoChangeLengthNotifier;
class SMILValue;

namespace dom {
class DOMSVGAnimatedLength;
class DOMSVGLength;
class SVGAnimationElement;
class SVGViewportElement;

class UserSpaceMetrics {
 public:
  enum class Type : uint32_t { This, Root };
  static GeckoFontMetrics DefaultFontMetrics();
  static GeckoFontMetrics GetFontMetrics(const Element* aElement);
  static WritingMode GetWritingMode(const Element* aElement);
  static float GetZoom(const Element* aElement);
  static CSSSize GetCSSViewportSizeFromContext(const nsPresContext* aContext);

  virtual ~UserSpaceMetrics() = default;

  virtual float GetEmLength(Type aType) const = 0;
  virtual float GetZoom() const = 0;
  virtual float GetRootZoom() const = 0;
  float GetExLength(Type aType) const;
  float GetChSize(Type aType) const;
  float GetIcWidth(Type aType) const;
  float GetCapHeight(Type aType) const;
  virtual float GetAxisLength(uint8_t aCtxType) const = 0;
  virtual CSSSize GetCSSViewportSize() const = 0;
  virtual float GetLineHeight(Type aType) const = 0;

 protected:
  virtual GeckoFontMetrics GetFontMetricsForType(Type aType) const = 0;
  virtual WritingMode GetWritingModeForType(Type aType) const = 0;
};

class UserSpaceMetricsWithSize : public UserSpaceMetrics {
 public:
  virtual gfx::Size GetSize() const = 0;
  float GetAxisLength(uint8_t aCtxType) const override;
};

class SVGElementMetrics final : public UserSpaceMetrics {
 public:
  explicit SVGElementMetrics(const SVGElement* aSVGElement,
                             const SVGViewportElement* aCtx = nullptr);

  float GetEmLength(Type aType) const override {
    return SVGContentUtils::GetFontSize(GetElementForType(aType));
  }
  float GetAxisLength(uint8_t aCtxType) const override;
  CSSSize GetCSSViewportSize() const override;
  float GetLineHeight(Type aType) const override;
  float GetZoom() const override;
  float GetRootZoom() const override;

 private:
  bool EnsureCtx() const;
  const Element* GetElementForType(Type aType) const;
  GeckoFontMetrics GetFontMetricsForType(Type aType) const override;
  WritingMode GetWritingModeForType(Type aType) const override;

  const SVGElement* mSVGElement;
  mutable const SVGViewportElement* mCtx;
};

class NonSVGFrameUserSpaceMetrics final : public UserSpaceMetricsWithSize {
 public:
  explicit NonSVGFrameUserSpaceMetrics(nsIFrame* aFrame);

  float GetEmLength(Type aType) const override;
  gfx::Size GetSize() const override;
  CSSSize GetCSSViewportSize() const override;
  float GetLineHeight(Type aType) const override;
  float GetZoom() const override;
  float GetRootZoom() const override;

 private:
  GeckoFontMetrics GetFontMetricsForType(Type aType) const override;
  WritingMode GetWritingModeForType(Type aType) const override;
  nsIFrame* mFrame;
};

}  // namespace dom

class SVGAnimatedLength {
  friend class AutoChangeLengthNotifier;
  friend class dom::DOMSVGAnimatedLength;
  friend class dom::DOMSVGLength;
  using DOMSVGLength = dom::DOMSVGLength;
  using SVGElement = dom::SVGElement;
  using SVGViewportElement = dom::SVGViewportElement;
  using UserSpaceMetrics = dom::UserSpaceMetrics;

 public:
  void Init(uint8_t aCtxType = SVGContentUtils::XY, uint8_t aAttrEnum = 0xff,
            float aValue = 0,
            uint8_t aUnitType = dom::SVGLength_Binding::SVG_LENGTHTYPE_NUMBER) {
    mAnimVal = mBaseVal = aValue;
    mBaseUnitType = mAnimUnitType = aUnitType;
    mAttrEnum = aAttrEnum;
    mCtxType = aCtxType;
    mIsAnimated = false;
    mIsBaseSet = false;
  }

  SVGAnimatedLength& operator=(const SVGAnimatedLength& aLength) {
    mBaseVal = aLength.mBaseVal;
    mAnimVal = aLength.mAnimVal;
    mBaseUnitType = aLength.mBaseUnitType;
    mAnimUnitType = aLength.mAnimUnitType;
    mIsAnimated = aLength.mIsAnimated;
    mIsBaseSet = aLength.mIsBaseSet;
    return *this;
  }

  nsresult SetBaseValueString(const nsAString& aValue, SVGElement* aSVGElement,
                              bool aDoSetAttr);
  void GetBaseValueString(nsAString& aValue) const;
  void GetAnimValueString(nsAString& aValue) const;

  float GetBaseValue(const SVGElement* aSVGElement) const {
    return mBaseVal * GetPixelsPerUnit(aSVGElement, mBaseUnitType);
  }

  float GetAnimValue(const SVGElement* aSVGElement) const {
    return mAnimVal * GetPixelsPerUnit(aSVGElement, mAnimUnitType);
  }
  float GetAnimValueWithZoom(const SVGElement* aSVGElement) const {
    return mAnimVal * GetPixelsPerUnitWithZoom(aSVGElement, mAnimUnitType);
  }
  float GetAnimValueWithZoom(nsIFrame* aFrame) const {
    return mAnimVal * GetPixelsPerUnitWithZoom(aFrame, mAnimUnitType);
  }
  float GetAnimValueWithZoom(const SVGViewportElement* aCtx) const {
    return mAnimVal * GetPixelsPerUnitWithZoom(aCtx, mAnimUnitType);
  }
  float GetAnimValueWithZoom(const UserSpaceMetrics& aMetrics) const {
    return mAnimVal * GetPixelsPerUnitWithZoom(aMetrics, mAnimUnitType);
  }

  uint8_t GetCtxType() const { return mCtxType; }
  uint8_t GetBaseUnitType() const { return mBaseUnitType; }
  uint8_t GetAnimUnitType() const { return mAnimUnitType; }
  bool IsPercentage() const {
    return mAnimUnitType == dom::SVGLength_Binding::SVG_LENGTHTYPE_PERCENTAGE;
  }
  float GetAnimValInSpecifiedUnits() const { return mAnimVal; }
  float GetBaseValInSpecifiedUnits() const { return mBaseVal; }

  bool HasBaseVal() const { return mIsBaseSet; }
  // Returns true if the animated value of this length has been explicitly
  // set (either by animation, or by taking on the base value which has been
  // explicitly set by markup or a DOM call), false otherwise.
  // If this returns false, the animated value is still valid, that is,
  // usable, and represents the default base value of the attribute.
  bool IsExplicitlySet() const { return mIsAnimated || mIsBaseSet; }

  bool IsAnimated() const { return mIsAnimated; }

  already_AddRefed<dom::DOMSVGAnimatedLength> ToDOMAnimatedLength(
      SVGElement* aSVGElement);

  UniquePtr<SMILAttr> ToSMILAttr(SVGElement* aSVGElement);

 private:
  float mAnimVal;
  float mBaseVal;
  uint8_t mBaseUnitType;
  uint8_t mAnimUnitType;
  uint8_t mAttrEnum : 6;  // element specified tracking for attribute
  uint8_t mCtxType : 2;   // X, Y or Unspecified
  bool mIsAnimated : 1;
  bool mIsBaseSet : 1;

  // These APIs returns the number of user-unit pixels per unit of the
  // given type, in a given context (frame/element/etc).
  float GetPixelsPerUnit(const SVGElement* aSVGElement,
                         uint8_t aUnitType) const;
  float GetPixelsPerUnitWithZoom(nsIFrame* aFrame, uint8_t aUnitType) const;
  float GetPixelsPerUnitWithZoom(const UserSpaceMetrics& aMetrics,
                                 uint8_t aUnitType) const;
  float GetPixelsPerUnitWithZoom(const SVGElement* aSVGElement,
                                 uint8_t aUnitType) const;
  float GetPixelsPerUnitWithZoom(const SVGViewportElement* aCtx,
                                 uint8_t aUnitType) const;

  // SetBaseValue and SetAnimValue set the value in user units. This may fail
  // if unit conversion fails e.g. conversion to ex or em units where the
  // font-size is 0.
  // SetBaseValueInSpecifiedUnits and SetAnimValueInSpecifiedUnits do not
  // perform unit conversion and are therefore infallible.
  nsresult SetBaseValue(float aValue, SVGElement* aSVGElement, bool aDoSetAttr);
  void SetBaseValueInSpecifiedUnits(float aValue, SVGElement* aSVGElement,
                                    bool aDoSetAttr);
  void SetAnimValue(float aValue, uint16_t aUnitType, SVGElement* aSVGElement);
  void SetAnimValueInSpecifiedUnits(float aValue, SVGElement* aSVGElement);
  nsresult NewValueSpecifiedUnits(uint16_t aUnitType,
                                  float aValueInSpecifiedUnits,
                                  SVGElement* aSVGElement);
  nsresult ConvertToSpecifiedUnits(uint16_t aUnitType, SVGElement* aSVGElement);
  already_AddRefed<DOMSVGLength> ToDOMBaseVal(SVGElement* aSVGElement);
  already_AddRefed<DOMSVGLength> ToDOMAnimVal(SVGElement* aSVGElement);

 public:
  struct SMILLength : public SMILAttr {
   public:
    SMILLength(SVGAnimatedLength* aVal, SVGElement* aSVGElement)
        : mVal(aVal), mSVGElement(aSVGElement) {}

    // These will stay alive because a SMILAttr only lives as long
    // as the Compositing step, and DOM elements don't get a chance to
    // die during that.
    SVGAnimatedLength* mVal;
    SVGElement* mSVGElement;

    // SMILAttr methods
    nsresult ValueFromString(const nsAString& aStr,
                             const dom::SVGAnimationElement* aSrcElement,
                             SMILValue& aValue,
                             bool& aPreventCachingOfSandwich) const override;
    SMILValue GetBaseValue() const override;
    void ClearAnimValue() override;
    nsresult SetAnimValue(const SMILValue& aValue) override;
  };
};

/**
 * This class is used by the SMIL code when a length is to be stored in a
 * SMILValue instance. Since SMILValue objects may be cached, it is necessary
 * for us to hold a strong reference to our element so that it doesn't
 * disappear out from under us if, say, the element is removed from the DOM
 * tree.
 */
class SVGLengthAndInfo {
 public:
  SVGLengthAndInfo() = default;

  explicit SVGLengthAndInfo(dom::SVGElement* aElement)
      : mElement(do_GetWeakReference(aElement->AsNode())) {}

  void SetInfo(dom::SVGElement* aElement) {
    mElement = do_GetWeakReference(aElement->AsNode());
  }

  dom::SVGElement* Element() const {
    nsCOMPtr<nsIContent> e = do_QueryReferent(mElement);
    return static_cast<dom::SVGElement*>(e.get());
  }

  bool operator==(const SVGLengthAndInfo& rhs) const {
    return mValue == rhs.mValue && mUnitType == rhs.mUnitType &&
           mCtxType == rhs.mCtxType;
  }

  float Value() const { return mValue; }

  uint8_t UnitType() const { return mUnitType; }

  void CopyFrom(const SVGLengthAndInfo& rhs) {
    mElement = rhs.mElement;
    mValue = rhs.mValue;
    mUnitType = rhs.mUnitType;
    mCtxType = rhs.mCtxType;
  }

  float ConvertUnits(const SVGLengthAndInfo& aTo) const;

  float ValueInPixels(const dom::UserSpaceMetrics& aMetrics) const;

  void Add(const SVGLengthAndInfo& aValueToAdd, uint32_t aCount);

  static void Interpolate(const SVGLengthAndInfo& aStart,
                          const SVGLengthAndInfo& aEnd, double aUnitDistance,
                          SVGLengthAndInfo& aResult);

  /**
   * Enables SVGAnimatedLength values to be copied into SVGLengthAndInfo
   * objects. Note that callers should also call SetInfo() when using this
   * method!
   */
  void CopyBaseFrom(const SVGAnimatedLength& rhs) {
    mValue = rhs.GetBaseValInSpecifiedUnits();
    mUnitType = rhs.GetBaseUnitType();
    mCtxType = rhs.GetCtxType();
  }

  void Set(float aValue, uint8_t aUnitType, uint8_t aCtxType) {
    mValue = aValue;
    mUnitType = aUnitType;
    mCtxType = aCtxType;
  }

 private:
  // We must keep a weak reference to our element because we may belong to a
  // cached baseVal SMILValue. See the comments starting at:
  // https://bugzilla.mozilla.org/show_bug.cgi?id=515116#c15
  // See also https://bugzilla.mozilla.org/show_bug.cgi?id=653497
  nsWeakPtr mElement;
  float mValue = 0.0f;
  uint8_t mUnitType = dom::SVGLength_Binding::SVG_LENGTHTYPE_NUMBER;
  uint8_t mCtxType = SVGContentUtils::XY;
};

}  // namespace mozilla

#endif  // DOM_SVG_SVGANIMATEDLENGTH_H_