Buttons - underlays
The base images
The base file consists of a single column of three button appearances.
The rows specify, from top to bottom, (i) the normal appearance of the button, (ii)
the pressed appearance, (iii) the highlighted appearance. For example, to make
a button "press down", one would normally draw a button with inverted edge highlights
and moved down and to the left by one pixel. But with this open draw-it-yourself
system, you can draw in any press-effect you like (squashed spheres, colour
changes, "ouch"-bubbles). All the images are separated by a one
pixel space, which can be used to draw a grid to help make the bounds of each image
clearer when drawing it. The pixel space also serves to prevent JPG compression
corrupting the edges of the buttons. If saving with JPG, fill the 1-pixel buffer
lines with a colour as near as possible to the adjoining button edges.