Artifact 0987d01d444a747c02aca0c13ae5fd4ee1186ab8:

• File demos/over-translated.tcl — part of check-in [806909ad23] at 2011-11-23 07:49:54 on branch infinite-plane — Modified the alpha over operator to behave like the other binary operators in general. Updated and added demos. (user: andreask size: 569) [more...]

def op_alpha_over_translated {
    label Over/Translated
    active { expr { [bases] == 2 } }
    setup_image {
	# We use the foreground image's luma as opacity (bright =
	# opaque, dark = transparent) to merge it with the background
	# image. At last we force fully opaque to avoid mix effects
	# against the canvas background color.

	show_image [crimp convert 2rgb \
			[crimp alpha over \
			     [crimp place \
				  [crimp alpha set \
				       [base] \
				       [crimp convert 2grey8 [base]]] \
				  -50 -50] \
			     [crimp place [base 1] 60 70]]]
    }
}