How to use UIGraphicsBeginImageContextWithOptions?
I've written this code to perform exactly the same thing described in the other post. It works on any iOS device with at least iOS 3.1.
_launcherView is the view that need to be photographed
CGFloat scale = 1.0;
if([[UIScreen mainScreen]respondsToSelector:@selector(scale)]) {
CGFloat tmp = [[UIScreen mainScreen]scale];
if (tmp > 1.5) {
scale = 2.0;
}
}
if(scale > 1.5) {
UIGraphicsBeginImageContextWithOptions(_launcherView.frame.size, NO, scale);
} else {
UIGraphicsBeginImageContext(_launcherView.frame.size);
}
[_launcherView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *screenshot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGRect upRect = CGRectMake(0, 0, _launcherView.frame.size.width*scale, (diff - offset)*scale);
CGImageRef imageRefUp = CGImageCreateWithImageInRect([screenshot CGImage], upRect);
[self.screenshot1 setFrame:CGRectMake(0, 0, screenshot1.frame.size.width, diff - offset)];
[screenshot1 setContentMode:UIViewContentModeTop];
UIImage * img1 = [UIImage imageWithCGImage:imageRefUp];
[self.screenshot1 setBackgroundImage:img1 forState:UIControlStateNormal];
CGImageRelease(imageRefUp);
CGRect downRect = CGRectMake(0, (diff - offset)*scale, _launcherView.frame.size.width*scale, (screenshot.size.height - diff + offset)*scale);
CGImageRef imageRefDown = CGImageCreateWithImageInRect([screenshot CGImage], downRect);
[self.screenshot2 setFrame:CGRectMake(0, screenshot1.frame.size.height , screenshot2.frame.size.width, _launcherView.frame.size.height - screenshot1.frame.size.height)];
[screenshot2 setContentMode:UIViewContentModeTop];
UIImage * img2 = [UIImage imageWithCGImage:imageRefDown];
[self.screenshot2 setBackgroundImage:img2 forState:UIControlStateNormal];
CGImageRelease(imageRefDown);