faster way to draw an image
- by iHorse
im trying to combine two images into a single image. unfortunately this has to be done very quickly in response to a user sliding a UISlider. i can combine the two images into a single image no problem. but the way I'm doing it is horribly slow. the sliders stick and jump rather frustratingly. i don't think i can throw the code into a background thread because i would run out of threads to quickly. i haven't actually tired that yet. below is my code. any ideas on how to speed it up would be helpful.
UIGraphicsBeginImageContext(CGSizeMake(bodyImage.theImage.image.size.width * 1.2, bodyImage.theImage.image.size.height * 1.2));
[bodyImage.theImage.image drawInRect:
CGRectMake(-2 + ((bodyImage.theImage.image.size.width * 1.2) - bodyImage.theImage.image.size.width)/2,
kHeadAdjust,
bodyImage.theImage.image.size.width * bodyImage.currentScale,
bodyImage.theImage.image.size.height * bodyImage.currentScale)];
if(isCustHead)
{
[Head.theImage.image drawInRect: CGRectMake((bodyImage.theImage.image.size.width * 1.2 - headWidth)/2 - 11,
0,
headWidth * 0.92,
headWidth * (Head.theImage.image.size.height/Head.theImage.image.size.width) * 0.92)];
}
else
{
[Head.theImage.image drawInRect: CGRectMake((bodyImage.theImage.image.size.width * 1.2 - (headWidth * defaultHeadAdjust))/2 - 10,
0,
(headWidth * defaultHeadAdjust * 0.92),
(headWidth * defaultHeadAdjust) * (Head.theImage.image.size.height/Head.theImage.image.size.width) * 0.92)];
}
drawSurface.theImage.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
