UIImage一些操作小技巧

二张图片合并（添加水印等等）

-(UIImage *)addImage:(UIImage *)image1 toImage:(UIImage *)image2
{
UIGraphicsBeginImageContext(image2.size);
//Draw image2
[image2 drawInRect:CGRectMake(0, 0, image2.size.width, image2.size.height)];
//Draw image1
[image1 drawInRect:CGRectMake(20, 20, image1.size.width, image1.size.height)];
UIImage *resultImage=UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return resultImage;
}

UIImage的等比率缩放

- (UIImage *)scaleImage:(UIImage *)image toScale:(float)scaleSize

{

UIGraphicsBeginImageContext(CGSizeMake(image.size.width * scaleSize, image.size.height * scaleSize);
[image drawInRect:CGRectMake(0, 0, image.size.width * scaleSize, image.size.height * scaleSize)];
UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return scaledImage;

}

自定长宽
- (UIImage *)reSizeImage:(UIImage *)image toSize:(CGSize)reSize

{
UIGraphicsBeginImageContext(CGSizeMake(reSize.width, reSize.height));
[image drawInRect:CGRectMake(0, 0, reSize.width, reSize.height)];
UIImage *reSizeImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return reSizeImage;

}

对特定View进行截图（必须先import QuzrtzCore.framework）

-(UIImage*)captureView:(UIView *)theView

{
CGRect rect = theView.frame;
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[theView.layer renderInContext:context];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return img;

}

UIImage一些操作小技巧

原文：http://www.cnblogs.com/CafeWing/p/3545702.html