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cappuccino/AppKit/CPAnimation.j
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2009-10-08 13:20:10 -07:00

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/*
* CPAnimation.j
* AppKit
*
* Created by Francisco Tolmasky.
* Copyright 2008, 280 North, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
@import <Foundation/CPObject.j>
@import "CAMediaTimingFunction.j"
/*
@global
@group CPAnimationCurve
*/
CPAnimationEaseInOut = 0;
/*
@global
@group CPAnimationCurve
*/
CPAnimationEaseIn = 1;
/*
@global
@group CPAnimationCurve
*/
CPAnimationEaseOut = 2;
/*
@global
@group CPAnimationCurve
*/
CPAnimationLinear = 3;
ACTUAL_FRAME_RATE = 0;
/*!
@ingroup appkit
@class CPAnimation
Manages an animation. Contains timing and progress information.
@par Delegate Methods
@delegate -(BOOL)animationShouldStart:(CPAnimation)animation;
Called at the beginning of \c -startAnimation.
@param animation the animation that will start
@return \c YES allows the animation to start.
\c NO stops the animation.
@delegate -(void)animationDidEnd:(CPAnimation)animation;
Called when an animation has completed.
@param animation the animation that completed
@delegate -(void)animationDidStop:(CPAnimation)animation;
Called when the animation was stopped (before completing).
@param animation the animation that was stopped
@delegate - (float)animation:(CPAnimation)animation valueForProgress:(float)progress;
The value from this method will be returned when CPAnimation's
\c currentValue method is called.
@param animation the animation to obtain the curve value for
@param progress the current animation progress
@return the curve value
*/
@implementation CPAnimation : CPObject
{
CPTimeInterval _lastTime;
CPTimeInterval _duration;
CPAnimationCurve _animationCurve;
CAMediaTimingFunction _timingFunction;
float _frameRate;
float _progress;
id _delegate;
CPTimer _timer;
}
/*!
Initializes the animation with a duration and animation curve.
@param aDuration the length of the animation
@param anAnimationCurve defines the animation's pace
@throws CPInvalidArgumentException if an invalid animation curve is specified
*/
- (id)initWithDuration:(float)aDuration animationCurve:(CPAnimationCurve)anAnimationCurve
{
self = [super init];
if (self)
{
_progress = 0.0;
_duration = MAX(0.0, aDuration);
_animationCurve = anAnimationCurve;
_frameRate = 60.0;
}
return self;
}
/*!
Sets the animation's pace.
@param anAnimationCurve the animation's pace
@throws CPInvalidArgumentException if an invalid animation curve is specified
*/
- (void)setAnimationCurve:(CPAnimationCurve)anAnimationCurve
{
switch (_animationCurve)
{
case CPAnimationEaseInOut: timingFunctionName = kCAMediaTimingFunctionEaseInEaseOut;
break;
case CPAnimationEaseIn: timingFunctionName = kCAMediaTimingFunctionEaseIn;
break;
case CPAnimationEaseOut: timingFunctionName = kCAMediaTimingFunctionEaseOut;
break;
case CPAnimationLinear: timingFunctionName = kCAMediaTimingFunctionLinear;
break;
default: [CPException raise:CPInvalidArgumentException
reason:"Invalid value provided for animation curve"];
break;
}
_animationCurve = anAnimationCurve;
_timingFunction = [CAMediaTimingFunction functionWithName:timingFunctionName];
}
/*!
Returns the animation's pace
*/
- (CPAnimationCurve)animationCurve
{
return _animationCurve;
}
/*!
Sets the animation's length.
@param aDuration the new animation length
@throws CPInvalidArgumentException if \c aDuration is negative
*/
- (void)setDuration:(CPTimeInterval)aDuration
{
if (aDuration < 0)
[CPException raise:CPInvalidArgumentException reason:"aDuration can't be negative"];
_duration = aDuration;
}
/*!
Returns the length of the animation.
*/
- (CPTimeInterval)duration
{
return _duration;
}
/*!
Sets the animation frame rate. This is not a guaranteed frame rate. 0 means to go as fast as possible.
@param frameRate the new desired frame rate
@throws CPInvalidArgumentException if \c frameRate is negative
*/
- (void)setFrameRate:(float)frameRate
{
if (frameRate < 0)
[CPException raise:CPInvalidArgumentException reason:"frameRate can't be negative"];
_frameRate = frameRate;
}
/*!
Returns the desired frame rate.
*/
- (float)frameRate
{
return _frameRate;
}
/*!
Returns the animation's delegate
*/
- (id)delegate
{
return _delegate;
}
/*!
Sets the animation's delegate.
@param aDelegate the new delegate
*/
- (void)setDelegate:(id)aDelegate
{
_delegate = aDelegate;
}
/*!
Starts the animation. The method calls \c -animationShouldStart:
on the delegate (if it implements it) to see if the animation
should begin.
*/
- (void)startAnimation
{
// If we're already animating, or our delegate stops us, animate.
if (_timer || _delegate && [_delegate respondsToSelector:@selector(animationShouldStart:)] && ![_delegate animationShouldStart:self])
return;
if (_progress === 1.0)
_progress = 0.0;
ACTUAL_FRAME_RATE = 0;
_lastTime = new Date();
_timer = [CPTimer scheduledTimerWithTimeInterval:0.0 target:self selector:@selector(animationTimerDidFire:) userInfo:nil repeats:YES];
}
/*
@ignore
*/
- (void)animationTimerDidFire:(CPTimer)aTimer
{
var currentTime = new Date(),
progress = MIN(1.0, [self currentProgress] + (currentTime - _lastTime) / (_duration * 1000.0));
_lastTime = currentTime;
++ACTUAL_FRAME_RATE;
[self setCurrentProgress:progress];
if (progress === 1.0)
{
[_timer invalidate];
_timer = nil;
if ([_delegate respondsToSelector:@selector(animationDidEnd:)])
[_delegate animationDidEnd:self];
}
}
/*!
Stops the animation before it has completed.
*/
- (void)stopAnimation
{
if (!_timer)
return;
[_timer invalidate];
_timer = nil;
if ([_delegate respondsToSelector:@selector(animationDidStop:)])
[_delegate animationDidStop:self];
}
/*!
Returns \c YES if the animation
is running.
*/
- (BOOL)isAnimating
{
return _timer;
}
/*!
Sets the animation's progress.
@param aProgress the animation's progress
*/
- (void)setCurrentProgress:(float)aProgress
{
_progress = aProgress;
}
/*!
Returns the animation's progress
*/
- (float)currentProgress
{
return _progress;
}
/*!
Returns the animation's timing progress.
*/
- (float)currentValue
{
var t = [self currentProgress];
if ([_delegate respondsToSelector:@selector(animation:valueForProgress:)])
return [_delegate animation:self valueForProgress:t];
var c1 = [],
c2 = [];
[_timingFunction getControlPointAtIndex:1 values:c1];
[_timingFunction getControlPointAtIndex:2 values:c2];
return CubicBezierAtTime(t,c1[0],c1[1],c2[0],c2[1],_duration);
}
@end
// currently used function to determine time
// 1:1 conversion to js from webkit source files
// UnitBezier.h, WebCore_animation_AnimationBase.cpp
var CubicBezierAtTime = function CubicBezierAtTime(t,p1x,p1y,p2x,p2y,duration)
{
var ax=0,bx=0,cx=0,ay=0,by=0,cy=0;
// `ax t^3 + bx t^2 + cx t' expanded using Horner's rule.
function sampleCurveX(t) {return ((ax*t+bx)*t+cx)*t;};
function sampleCurveY(t) {return ((ay*t+by)*t+cy)*t;};
function sampleCurveDerivativeX(t) {return (3.0*ax*t+2.0*bx)*t+cx;};
// The epsilon value to pass given that the animation is going to run over |duration| seconds. The longer the animation, the more precision is needed in the timing function result to avoid ugly discontinuities.
function solveEpsilon(duration) {return 1.0/(200.0*duration);};
function solve(x,epsilon) {return sampleCurveY(solveCurveX(x,epsilon));};
// Given an x value, find a parametric value it came from.
function solveCurveX(x,epsilon) {var t0,t1,t2,x2,d2,i;
function fabs(n) {if(n>=0) {return n;}else {return 0-n;}};
// First try a few iterations of Newton's method -- normally very fast.
for(t2=x, i=0; i<8; i++) {x2=sampleCurveX(t2)-x; if(fabs(x2)<epsilon) {return t2;} d2=sampleCurveDerivativeX(t2); if(fabs(d2)<1e-6) {break;} t2=t2-x2/d2;}
// Fall back to the bisection method for reliability.
t0=0.0; t1=1.0; t2=x; if(t2<t0) {return t0;} if(t2>t1) {return t1;}
while(t0<t1) {x2=sampleCurveX(t2); if(fabs(x2-x)<epsilon) {return t2;} if(x>x2) {t0=t2;}else {t1=t2;} t2=(t1-t0)*.5+t0;}
return t2; // Failure.
};
// Calculate the polynomial coefficients, implicit first and last control points are (0,0) and (1,1).
cx=3.0*p1x; bx=3.0*(p2x-p1x)-cx; ax=1.0-cx-bx; cy=3.0*p1y; by=3.0*(p2y-p1y)-cy; ay=1.0-cy-by;
// Convert from input time to parametric value in curve, then from that to output time.
return solve(t, solveEpsilon(duration));
};