Question

Please refer to the code for rotating the piechart when any sice is touched:

-(void)pieChart:(CPTPieChart *)plot sliceWasSelectedAtRecordIndex:(NSUInteger)index{

[self rotatePieChart:plot];

}

-(void)rotatePieChart:(CPTPieChart *)plot {    

[CATransaction begin];
{
    CABasicAnimation *rotation = [CABasicAnimation animationWithKeyPath:@"transform"];
    CATransform3D transform = CATransform3DMakeRotation(-45, 0, 0, 1);
    rotation.toValue = [NSValue valueWithCATransform3D:transform];
    rotation.fillMode = kCAFillModeForwards;
    rotation.duration = 1.0f;
    rotation.cumulative=YES;
    rotation.removedOnCompletion = NO; 

    [plot addAnimation:rotation forKey:@"rotation"];

}
[CATransaction commit];

}

ON first Tap the piechart rotates but on subsequent taps nothing happens.

Answer 1

Instead of rotating the whole plot layer, animate only the startAngle property. I suspect the hit-detection code is getting confused by the rotated coordinate system.