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copied!<p>Take the approach outlined by Cirrostratus, keep a cached copy of it, and then apply a transform to change the size and/or position of the image while dragging.</p> <p>(warning, this is not functional/tested code, but should get you started)</p> <pre><code>-(UIImage*)addGlowToImage:(UIImage*)imageInput; { CGRect newSize = imageInput.bounds; CGImageRef theImage = imageInput.CGImage; // expand the size to handle the "glow" newSize.size.width += 6.0; newSize.size.height += 6.0; UIGraphicsBeginImageContext(newSize); CGContextRef ctx = UIGraphicsGetCurrentContext(); CGContextBeginTransparencyLayerWithRect(ctx, newSize, NULL); CGContextClearRect(ctx, newSize); // you can repeat this process to build glow. CGContextDrawImage(ctx, newSize, theImage); CGContextSetAlpha(ctx, 0.2); CGContextEndTransparencyLayer(ctx); // draw the original image into the context, offset to be centered; CGRect centerRect = inputImage.bounds; centerRect.origin.x += 3.0; centerRect.origin.y += 3.0; CGContextDrawImage(ctx, centerRect, theImage); result = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return result; } </code></pre> <p>Then in your method while scaling you would do something like:</p> <pre><code>// assumes UIImage *cachedImage = [self addGlowToImage:origImage]; has been called already. // assumes ivars for scale exists CGRect newRect = cachedImage.bounds; newRect.size.width += scale; newRect.size.height += scale; [cachedImage drawInRect:newRect]; // image will be scaled to fill destination rectangle. </code></pre> <p>Definitely take a look at the apple docs. A good starting place is the <a href="http://developer.apple.com/iphone/library/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/Introduction/Introduction.html" rel="noreferrer">Quartz 2D Programming Guide</a>.</p>

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