Line(BitmapHandle, x1, y1, x2, y2, Colour)

Line allows you to draw a line from (including) (x1, y1) to (including)(x2, y2).
The colour is specified through its index.

Return Value:
0 if everything was OK or -1 if you indicated a non-valid bitmap.

Example:

b = createBitmap(200, 200)
if b = -1
print("Ooops, could not create the bitmap....\n")
else

// White background
clearBitmap(b, RGB(255, 255, 255))

for i=0 to 200 step 10

// We take random colours...
line(b, 0, i, i, 199, random(256))
line(b, i, 0, 199, i, random(256))

end for

saveGIFFile("lines.gif", b)

end if

For more details see the Bitmap topic.