For information, pure Computer graphics bug

[devEric69]

Hello,

I've found this bug (afaik, unrelated with X11 or GDI). I don't have the skills to understand where to fix it logically.

With the dark colored theme of my PC (Linux),
in the wuline_test program,
when drawing the spiral,
in the AlphaBlendPixel procedure (ACanvas: TfpgCanvas; X, Y: integer; R, G, B: word; ARatio: Double),
the line var LNew.Blue := round...
...raises a range check error with a B*ARatio that is negative. Indeed, LNew.Blue is typed as Byte, i.e. (0..255).

Regards.