o mean “don’t move this pixel in the original layer”, whereas a white pixel might mean “move this 10 pixels to the right”. The idea of constructing a pixel value to displacement mapping makes conceptual sense to me, but I find it a little hard to visualise what that actually means. A worked example would probably help!</p>
<p>Let’s start by creating some ggplot layers that each contain semi-transparent triangles:</p>
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