Saving UIView contents in iOS 4 with real size of the images inside (i.e. scale contentes up for save)

Question

I have an UIView with many UIImageViews as subviews. The app runs on iOS4 and I use images with retina display resolution (i.e. the images load with scale = 2)

I wa

Answer 1

Couldn't you just create a new graphics context at the desired size, use a CGAffineTransform to scale it down, render the root UIView's root layer, restore the context to the original size and render the image? Haven't tried this for retina content, but this seems to work well for large images that have been scaled down in UIImageViews...

something like:

CGSize originalSize = myOriginalImage.size; //or whatever

//create context
UIGraphicsBeginImageContext(originalSize);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context); //1 original context

// translate/flip the graphics context (for transforming from CG* coords to UI* coords
CGContextTranslateCTM(context, 0, originalSize.height);
CGContextScaleCTM(context, 1.0, -1.0);

//original image
CGContextDrawImage(context, CGRectMake(0,0,originalSize.width,originalSize.height), myOriginalImage.CGImage);

CGContextRestoreGState(context);//1 restore to original for UIView render;

//scaling
CGFloat wratio = originalSize.width/self.view.frame.size.width;
CGFloat hratio = originalSize.height/self.view.frame.size.height;

//scale context to match view size
CGContextSaveGState(context); //1 pre-scaled size
CGContextScaleCTM(context, wratio, hratio);

//render 
[self.view.layer renderInContext:context];

CGContextRestoreGState(context);//1  restore to pre-scaled size;

UIImage *exportImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();