Ugh. Is my math (and logic) right?

[CharlieJV]

Hey, thanks for the help!

I wound up going back to the approach in the OP.  For the moment.  I'm on the fence.

All of this to put together an "RgbaLine" statement.

https://www.reddit.com/r/BASICAnywhereMa...the_works/

[bplus]

"Problem solved with a little security (last two lines added to bLine):"

I think if you subst in the first and last i to the pset values you will see the first and last point on line are already covered. Also if you want lines with transparencies doubling on first and last will show the color more like doing a circle fill with circles using alpha colors.

Try the 2 versions using alpha and see.

Code: (Select All)

Screen _NewImage(800, 600, 32)

Color &H30FFFFFF

For x = 1 To 20

    cLine x + 100, 10, x + 100, 500

    bLine x + 200, 10, x + 200, 500

Next



Sub cLine (x1, y1, x2, y2)

    dx = x2 - x1

    dy = y2 - y1

    dist = Sqr(dx * dx + dy * dy)

    dx = dx / dist

    dy = dy / dist

    For i = 0 To dist

        PSet (x1 + dx * i, y1 + dy * i)

    Next

    PSet (x1, y1)

    PSet (x2, y2)

End Sub



Sub bLine (x1, y1, x2, y2)

    dx = x2 - x1

    dy = y2 - y1

    dist = Sqr(dx * dx + dy * dy)

    dx = dx / dist

    dy = dy / dist

    For i = 0 To dist

        PSet (x1 + dx * i, y1 + dy * i)

    Next

End Sub