The Unroll ) method modifies the work pixels array for the next cell. It draws the roll onto the work pixels. This method first calculates the offset that it needs to use for drawing each-line of the roll. It then loops through each line of the roll, copying scan lines, from the new image onto the work_pixels array. The pixels that are exposed due to the left offset of each line are filled in with pixels from the static fill pixels array. Another loop then increments though each pixel on the top and the bottom lines of the roll, brightening pixels on the top line and darkening pixels on the bottom line.
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