iPhone Dev SDK Forum - View Single Post - Saving a Quartz Context to the Camera Roll. How do I do it? :)

SkylarEC · 11-23-2008, 04:42 AM

I don't know about the black thumbnail. The image is flipped because the CoreGraphics drawing surface' y axis is correct, and UIKit's y axis is inverted (for some weird reason). You will need to translate the grid and scale the image accordingly. Use these two lines:

Code:

	CGContextTranslateCTM(UIGraphicsGetCurrentContext, 0.0, CGImageGetHeight(theImage));  //Whereas theImage is a CGImageRef.  Using that is much more accurate than feeding in a height variable, but if you must, use a CGFloat variable.
	CGContextScaleCTM(UIGraphicsGetCurrentContext, 1.0, -1.0);