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02.12.2012 23:20:00 • Categories: Objective-C • Tags: UIImage, Objective-C

Objective-C: resize UIImage proportional

//the following is appropriate call to do this if img is the UIImage instance.
//img=[img scaleProportionalToSize:CGSizeMake(320, 480)];
@interface UIImage (UIImageFunctions)


(UIImage *) scaleToSize: (CGSize)size;


(UIImage *) scaleProportionalToSize: (CGSize)size;
@end
@implementation UIImage (UIImageFunctions)


(UIImage *) scaleToSize: (CGSize)size
{
// Scalling selected image to targeted size
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(NULL, size.width, size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);
CGContextClearRect(context, CGRectMake(0, 0, size.width, size.height));
if(self.imageOrientation == UIImageOrientationRight)
{
CGContextRotateCTM(context, -M_PI_2);
CGContextTranslateCTM(context, -size.height, 0.0f);
CGContextDrawImage(context, CGRectMake(0, 0, size.height, size.width), self.CGImage);
}
else
CGContextDrawImage(context, CGRectMake(0, 0, size.width, size.height), self.CGImage);
CGImageRef scaledImage=CGBitmapContextCreateImage(context);
CGColorSpaceRelease(colorSpace);
CGContextRelease(context);
UIImage *image = [UIImage imageWithCGImage: scaledImage];
CGImageRelease(scaledImage);
return image;
}


(UIImage ) scaleProportionalToSize: (CGSize)size1
{
if(self.size.width>self.size.height)
{
NSLog(@"LandScape");
size1=CGSizeMake((self.size.width/self.size.height)size1.height,size1.height);
}
else
{
NSLog(@"Potrait");
size1=CGSizeMake(size1.width,(self.size.height/self.size.width)*size1.width);
}
return [self scaleToSize:size1];
}


@end

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