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December 15, 2015 13:18
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This is a category on UIImage.
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- (UIImage *)rxScalePropertionallyToMaximumSize:(CGSize)maxSize blendMode:(CGBlendMode)blendMode alpha:(CGFloat)alpha scale:(CGFloat)scale { | |
if ((maxSize.width < 1.0e-15) || (maxSize.height < 1.0e-15)) return nil; | |
CGSize imageSize = self.size; | |
CGSize scaleFactors = { | |
.width = maxSize.width / imageSize.width, | |
.height = maxSize.height / imageSize.height, | |
}; | |
CGFloat scaleFactor = MIN(scaleFactors.width, scaleFactors.height); | |
CGSize newSize = { | |
.width = imageSize.width * scaleFactor, | |
.height = imageSize.height * scaleFactor | |
}; | |
CGRect imageFrame = (CGRect){ | |
.origin = CGPointZero, | |
.size = newSize | |
}; | |
UIGraphicsBeginImageContextWithOptions(newSize, YES, scale); | |
[self drawInRect:imageFrame blendMode:blendMode alpha:alpha]; | |
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext(); | |
UIGraphicsEndImageContext(); | |
return newImage; | |
} |
I think this version will work.
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This is a category on UIImage. It's intended to take a photo from the camera, image library or camera roll and shrink it. (The input size is smaller than the original size.)
But I've been having a lot of problems getting it to work with all orientations and sources.