カテゴリUIImageのトリミング方法の追加
まずUIImageのカテゴリを作成します
メソッドの呼び出し
//.h
@interface UIImage(UIImageScale)
-(UIImage*)getSubImage:(CGRect)rect;
-(UIImage*)scaleToSize:(CGSize)size;
@end
//.m
@implementation UIImage(UIImageScale)
//
-(UIImage*)getSubImage:(CGRect)rect
{
CGImageRef subImageRef = CGImageCreateWithImageInRect(self.CGImage, rect);
CGRect smallBounds = CGRectMake(0, 0, CGImageGetWidth(subImageRef), CGImageGetHeight(subImageRef));
UIGraphicsBeginImageContext(smallBounds.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextDrawImage(context, smallBounds, subImageRef);
UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];
UIGraphicsEndImageContext();
return smallImage;
}
//
-(UIImage*)scaleToSize:(CGSize)size
{
CGFloat width = CGImageGetWidth(self.CGImage);
CGFloat height = CGImageGetHeight(self.CGImage);
float verticalRadio = size.height*1.0/height;
float horizontalRadio = size.width*1.0/width;
float radio = 1;
if(verticalRadio>1 && horizontalRadio>1)
{
radio = verticalRadio > horizontalRadio ? horizontalRadio : verticalRadio;
}
else
{
radio = verticalRadio < horizontalRadio ? verticalRadio : horizontalRadio;
}
width = width*radio;
height = height*radio;
int xPos = (size.width - width)/2;
int yPos = (size.height-height)/2;
// bitmap context
// context
UIGraphicsBeginImageContext(size);
//
[self drawInRect:CGRectMake(xPos, yPos, width, height)];
// context
UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
// context
UIGraphicsEndImageContext();
//
return scaledImage;
}
@end
メソッドの呼び出し
UIImage *image = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://img21.mtime.cn/mg/2011/09/24/112524.53149978.jpg"]] ];
//
image = [image getSubImage:CGRectMake(10, 10, 70, 80)];
//
image = [image scaleToSize:CGSizeMake(200, 300)];
NSLog(@"image.size:%@",NSStringFromCGSize(CGSizeMake(imageView.image.size.width, imageView.image.size.height))); //