capp_lint CPAnimation.j.

Reviewed by me.
This commit is contained in:
Francisco Tolmasky authored and Francisco Ryan Tolmasky I committed 2010-12-02 10:38:51 -08:00
1 parent e71cbfbde2
commit dd560fb78c
1 file changed
+90 -14
+90 -14
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@@ -312,7 +312,7 @@ ACTUAL_FRAME_RATE = 0;
[_timingFunction getControlPointAtIndex:1 values:c1];
[_timingFunction getControlPointAtIndex:2 values:c2];
return CubicBezierAtTime(t,c1[0],c1[1],c2[0],c2[1],_duration);
return CubicBezierAtTime(t, c1[0], c1[1], c2[0], c2[1], _duration);
}
@end
@@ -320,28 +320,104 @@ ACTUAL_FRAME_RATE = 0;
// 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 CubicBezierAtTime = function CubicBezierAtTime(t, p1x, p1y, p2x, p2y, duration)
{
var ax=0,bx=0,cx=0,ay=0,by=0,cy=0;
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;};
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));};
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;}};
function solveCurveX(x, epsilon)
{
var t0,
t1,
t2 = x,
x2,
d2,
i = 0;
// 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;}
for (; i < 8; i++)
{
x2 = sampleCurveX(t2) - x;
if (ABS(x2) < epsilon)
return t2;
d2 = sampleCurveDerivativeX(t2);
if (ABS(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;}
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 (ABS(x2 - x) < epsilon)
return t2;
if (x > x2)
t0 = t2;
else
t1 = t2;
t2 = (t1 - t0) * 0.5 + 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;
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));
};