我想调整UIImage的大小,同时保持其纵横比.我已经写了下面的代码,但是没有按预期的方式工作.
码
-(UIImage * ) scaleImage: (UIImage * ) image toSize: (CGSize) targetSize {
CGFloat scaleFactor = 1.0;
if (image.size.width > targetSize.width || image.size.height > targetSize.height)
if (!((scaleFactor = (targetSize.width / image.size.width)) > (targetSize.height / image.size.height))) //scale to fit width,or
scaleFactor = targetSize.height / image.size.height; // scale to fit heigth.
UIGraphicsBeginImageContext(targetSize);
CGRect rect = CGRectMake((targetSize.width - image.size.width * scaleFactor) / 2,(targetSize.height - image.size.height * scaleFactor) / 2,image.size.width * scaleFactor,image.size.height * scaleFactor);
[image drawInRect: rect];
UIImage * scaledImage = UIGraphicsGetimageFromCurrentimageContext();
UIGraphicsEndImageContext();
return scaledImage;
}
这里究竟是错的？
解决方法
我在几个项目中使用类似的东西：
- (UIImage*) scaleImage:(UIImage*)image toSize:(CGSize)newSize {
CGSize scaledSize = newSize;
float scaleFactor = 1.0;
if( image.size.width > image.size.height ) {
scaleFactor = image.size.width / image.size.height;
scaledSize.width = newSize.width;
scaledSize.height = newSize.height / scaleFactor;
}
else {
scaleFactor = image.size.height / image.size.width;
scaledSize.height = newSize.height;
scaledSize.width = newSize.width / scaleFactor;
}
UIGraphicsBeginImageContextWithOptions( scaledSize,NO,0.0 );
CGRect scaledImageRect = CGRectMake( 0.0,0.0,scaledSize.width,scaledSize.height );
[image drawInRect:scaledImageRect];
UIImage* scaledImage = UIGraphicsGetimageFromCurrentimageContext();
UIGraphicsEndImageContext();
return scaledImage;
}