Functional Fills with Vecto

I’ve been wanting to do exclusive-or functional fill in vecto for a while, so tonight I delved in. I added a pixel function to the graphics state and kept the default as the normal alpha-blending it was already doing. The pixel function signature is a bit clumsy, but it was easy to knock up a couple of functional fill demos. Programmer art alert!

XOR pixel function

This is a cyan background, and a circle drawn with an XOR function, white fill, and green stroke. From this you can see that the fill happened before the stroke, since the stroke is half-and-half.

OR pixel function

And this demonstrates an inclusive-OR fill: the standard additive colour chart.

2 Responses to “Functional Fills with Vecto”

  1. Skye says:

    LOOK how pretty that is! How long were you working on it, to get it right? PS That cyan color will ALWAYS say ‘computer!’ to me!

  2. elbeno says:

    Well, Gary kept me distracted, so I started on it about 9. But it was easy really – I was done in about an hour. All I had to do was redirect the inner pixel drawing bit to a function, transplant the default, and hook up the accessor/mutator functions in the graphics state. The XOR and OR pixel functions were a simple test.

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