将图片缩放（质量和比例变化）

- (UIImage *)resizeImage:(UIImage *)image

             withQuality:(CGInterpolationQuality)quality

                    rate:(CGFloat)rate

{

UIImage *resized = nil;

CGFloat width = image.size.width * rate;

CGFloat height = image.size.height * rate;

UIGraphicsBeginImageContext(CGSizeMake(width, height));

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextSetInterpolationQuality(context, quality);

[image drawInRect:CGRectMake(0, 0, width, height)];

resized = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return resized;

}

将图片缩放（质量和比例变化）

原文：http://blog.csdn.net/zh_2608/article/details/44195015