gecko/layout/style/nsStyleAnimation.h

338 lines
13 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is nsStyleAnimation.
*
* The Initial Developer of the Original Code is
* The Mozilla Corporation.
* Portions created by the Initial Developer are Copyright (C) 2009
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Daniel Holbert <dholbert@mozilla.com>, Mozilla Corporation
* L. David Baron <dbaron@dbaron.org>, Mozilla Corporation
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/* Utilities for animation of computed style values */
#ifndef nsStyleAnimation_h_
#define nsStyleAnimation_h_
#include "prtypes.h"
#include "nsAString.h"
#include "nsCSSProperty.h"
#include "nsCoord.h"
#include "nsColor.h"
class nsCSSDeclaration;
class nsIContent;
class nsPresContext;
class nsStyleContext;
struct nsCSSValueList;
struct nsCSSValuePair;
/**
* Utility class to handle animated style values
*/
class nsStyleAnimation {
public:
class Value;
// Mathematical methods
// --------------------
/**
* Adds |aCount| copies of |aValueToAdd| to |aDest|. The result of this
* addition is stored in aDest.
*
* Note that if |aCount| is 0, then |aDest| will be unchanged. Also, if
* this method fails, then |aDest| will be unchanged.
*
* @param aDest The value to add to.
* @param aValueToAdd The value to add.
* @param aCount The number of times to add aValueToAdd.
* @return PR_TRUE on success, PR_FALSE on failure.
*/
static PRBool Add(Value& aDest, const Value& aValueToAdd,
PRUint32 aCount) {
return AddWeighted(1.0, aDest, aCount, aValueToAdd, aDest);
}
/**
* Calculates a measure of 'distance' between two values.
*
* This measure of Distance is guaranteed to be proportional to
* portions passed to Interpolate, Add, or AddWeighted. However, for
* some types of Value it may not produce sensible results for paced
* animation.
*
* If this method succeeds, the returned distance value is guaranteed to be
* non-negative.
*
* @param aStartValue The start of the interval for which the distance
* should be calculated.
* @param aEndValue The end of the interval for which the distance
* should be calculated.
* @param aDistance The result of the calculation.
* @return PR_TRUE on success, PR_FALSE on failure.
*/
static PRBool ComputeDistance(const Value& aStartValue,
const Value& aEndValue,
double& aDistance);
/**
* Calculates an interpolated value that is the specified |aPortion| between
* the two given values.
*
* This really just does the following calculation:
* aResultValue = (1.0 - aPortion) * aStartValue + aPortion * aEndValue
*
* @param aStartValue The value defining the start of the interval of
* interpolation.
* @param aEndValue The value defining the end of the interval of
* interpolation.
* @param aPortion A number in the range [0.0, 1.0] defining the
* distance of the interpolated value in the interval.
* @param [out] aResultValue The resulting interpolated value.
* @return PR_TRUE on success, PR_FALSE on failure.
*/
static PRBool Interpolate(const Value& aStartValue,
const Value& aEndValue,
double aPortion,
Value& aResultValue) {
NS_ABORT_IF_FALSE(0.0 <= aPortion && aPortion <= 1.0, "out of range");
return AddWeighted(1.0 - aPortion, aStartValue, aPortion, aEndValue,
aResultValue);
}
/**
* Does the calculation:
* aResultValue = aCoeff1 * aValue1 + aCoeff2 * aValue2
*
* @param [out] aResultValue The resulting interpolated value. May be
* the same as aValue1 or aValue2.
* @return PR_TRUE on success, PR_FALSE on failure.
*
* NOTE: Current callers always pass aCoeff1 and aCoeff2 >= 0. They
* are currently permitted to be negative; however, if, as we add
* support more value types types, we find that this causes
* difficulty, we might change this to restrict them to being
* positive.
*/
static PRBool AddWeighted(double aCoeff1, const Value& aValue1,
double aCoeff2, const Value& aValue2,
Value& aResultValue);
// Type-conversion methods
// -----------------------
/**
* Creates a computed value for the given specified value
* (property ID + string). A style context is needed in case the
* specified value depends on inherited style or on the values of other
* properties.
*
* NOTE: This method uses GetPrimaryShell() to access the style system,
* so it should only be used for style that applies to all presentations,
* rather than for style that only applies to a particular presentation.
* XXX Once we get rid of multiple presentations, we can remove the above
* note.
*
* @param aProperty The property whose value we're computing.
* @param aTargetElement The content node to which our computed value is
* applicable.
* @param aSpecifiedValue The specified value, from which we'll build our
* computed value.
* @param [out] aComputedValue The resulting computed value.
* @return PR_TRUE on success, PR_FALSE on failure.
*/
static PRBool ComputeValue(nsCSSProperty aProperty,
nsIContent* aElement,
const nsAString& aSpecifiedValue,
Value& aComputedValue);
/**
* Creates a specified value for the given computed value.
*
* The first form fills in one of the nsCSSType types into the void*;
* for some types this means that the void* is pointing to memory
* owned by the nsStyleAnimation::Value. (For all complex types, the
* nsStyleAnimation::Value owns the necessary objects so that the
* caller does not need to do anything to free them. However, this
* means that callers using the void* variant must keep
* |aComputedValue| alive longer than the structure into which they've
* filled the value.)
*
* @param aProperty The property whose value we're uncomputing.
* @param aPresContext The presentation context for the document in
* which we're working.
* @param aComputedValue The computed value to be converted.
* @param [out] aSpecifiedValue The resulting specified value.
* @return PR_TRUE on success, PR_FALSE on failure.
*/
static PRBool UncomputeValue(nsCSSProperty aProperty,
nsPresContext* aPresContext,
const Value& aComputedValue,
void* aSpecifiedValue);
static PRBool UncomputeValue(nsCSSProperty aProperty,
nsPresContext* aPresContext,
const Value& aComputedValue,
nsAString& aSpecifiedValue);
/**
* Gets the computed value for the given property from the given style
* context.
*
* @param aProperty The property whose value we're looking up.
* @param aStyleContext The style context to check for the computed value.
* @param [out] aComputedValue The resulting computed value.
* @return PR_TRUE on success, PR_FALSE on failure.
*/
static PRBool ExtractComputedValue(nsCSSProperty aProperty,
nsStyleContext* aStyleContext,
Value& aComputedValue);
/**
* The types and values for the values that we extract and animate.
*/
enum Unit {
eUnit_Null, // not initialized
eUnit_Normal,
eUnit_Auto,
eUnit_None,
eUnit_Enumerated,
eUnit_Coord,
eUnit_Percent,
eUnit_Float,
eUnit_Color,
eUnit_CSSValuePair, // nsCSSValuePair* (never null)
eUnit_Dasharray, // nsCSSValueList* (never null)
eUnit_Shadow // nsCSSValueList* (may be null)
};
class Value {
private:
Unit mUnit;
union {
PRInt32 mInt;
nscoord mCoord;
float mFloat;
nscolor mColor;
nsCSSValuePair* mCSSValuePair;
nsCSSValueList* mCSSValueList;
} mValue;
public:
Unit GetUnit() const {
NS_ASSERTION(mUnit != eUnit_Null, "uninitialized");
return mUnit;
}
// Accessor to let us verify assumptions about presence of null unit,
// without tripping the assertion in GetUnit().
PRBool IsNull() const {
return mUnit == eUnit_Null;
}
PRInt32 GetIntValue() const {
NS_ASSERTION(mUnit == eUnit_Enumerated, "unit mismatch");
return mValue.mInt;
}
nscoord GetCoordValue() const {
NS_ASSERTION(mUnit == eUnit_Coord, "unit mismatch");
return mValue.mCoord;
}
float GetPercentValue() const {
NS_ASSERTION(mUnit == eUnit_Percent, "unit mismatch");
return mValue.mFloat;
}
float GetFloatValue() const {
NS_ASSERTION(mUnit == eUnit_Float, "unit mismatch");
return mValue.mFloat;
}
nscolor GetColorValue() const {
NS_ASSERTION(mUnit == eUnit_Color, "unit mismatch");
return mValue.mColor;
}
nsCSSValuePair* GetCSSValuePairValue() const {
NS_ASSERTION(IsCSSValuePairUnit(mUnit), "unit mismatch");
return mValue.mCSSValuePair;
}
nsCSSValueList* GetCSSValueListValue() const {
NS_ASSERTION(IsCSSValueListUnit(mUnit), "unit mismatch");
return mValue.mCSSValueList;
}
explicit Value(Unit aUnit = eUnit_Null) : mUnit(aUnit) {
NS_ASSERTION(aUnit == eUnit_Null || aUnit == eUnit_Normal ||
aUnit == eUnit_Auto || aUnit == eUnit_None,
"must be valueless unit");
}
Value(const Value& aOther) : mUnit(eUnit_Null) { *this = aOther; }
enum EnumeratedConstructorType { EnumeratedConstructor };
Value(PRInt32 aInt, EnumeratedConstructorType);
enum CoordConstructorType { CoordConstructor };
Value(nscoord aLength, CoordConstructorType);
enum PercentConstructorType { PercentConstructor };
Value(float aPercent, PercentConstructorType);
enum FloatConstructorType { FloatConstructor };
Value(float aFloat, FloatConstructorType);
enum ColorConstructorType { ColorConstructor };
Value(nscolor aColor, ColorConstructorType);
~Value() { FreeValue(); }
void SetNormalValue();
void SetAutoValue();
void SetNoneValue();
void SetIntValue(PRInt32 aInt, Unit aUnit);
void SetCoordValue(nscoord aCoord);
void SetPercentValue(float aPercent);
void SetFloatValue(float aFloat);
void SetColorValue(nscolor aColor);
// These setters take ownership of |aValue|, and are therefore named
// "SetAndAdopt*".
void SetAndAdoptCSSValueListValue(nsCSSValueList *aValue, Unit aUnit);
void SetAndAdoptCSSValuePairValue(nsCSSValuePair *aValue, Unit aUnit);
Value& operator=(const Value& aOther);
PRBool operator==(const Value& aOther) const;
PRBool operator!=(const Value& aOther) const
{ return !(*this == aOther); }
private:
void FreeValue();
static PRBool IsCSSValuePairUnit(Unit aUnit) {
return aUnit == eUnit_CSSValuePair;
}
static PRBool IsCSSValueListUnit(Unit aUnit) {
return aUnit == eUnit_Dasharray || aUnit == eUnit_Shadow;
}
};
};
#endif