Re:ZX Spectrum Graphics Magic: The Basics Every Spectrum Fan...
by praptak on Tuesday June 17, 2025 @04:10AM
(#44296775)
There was also the screen border which generally had to have one color but you could use a similar trick to draw static stripes on it (ZX wasn't fast enough to change the color more than a few times per scan line, so you could not really draw more than stripes of varying width).
I remember a game that had a welcome screen which had matching stripes on the real screen and then drew some pixel patterns on it to create an illusion of drawing individual pixels on the border.
Graphics often looked a little weird, because of the hard limit of one color 'palette' (1 ink color and 1 paper color) per 8x8 pixel grid.
However, if you had cycles to spare, there was a cool hack that allowed one palette for each 8x1 pixel slice. By synchronizing with the ULA, you could overwrite the attribute row at each horizontal blanking interval.
The only time you'd have cycles to spare, of course, is when you weren't doing anything else whatsoever. But it made for pretty "press any key" welcome screens.