OpenEuphoria

Re: PAINT in Basic...

• Posted by Pete Eberlein <xseal at HARBORSIDE.COM> Jun 26, 1997
• 926 views

Here's two versions of painting procedures that I use:
Paint is like the basic statement
Fill is like in picture editing programs

--- code begins

procedure paint(object tile, sequence p, integer targ)
-- replaces all pixels bounded by targ colored pixels starting at some
point p
-- tile may be an atom for a solid color
--  or a 2-d sequence of pixels to be tiled
-- warning: this procedure is not aware of screen boundaries - be sure
that
--  the object to be painted has a closed border
    sequence stack, testp, scan
    integer index, ok
    stack = {{p, 0}}
    index = 1
    while index <= length(stack) do
        p = stack[index][1]
-- scoot all the way to the left
        while get_pixel(p-{1,0}) != targ do
            p[1] = p[1] - 1
        end while
        stack[index][1] = p
-- set flags
        scan = {0,0}
-- scan across current line of target color
        while get_pixel(p) != targ do
-- look for target color above/below current pixel
            for z = 1 to 2 do
                testp = p - {0, 3 - 2 * z}
                if (get_pixel(testp) != targ) then
                    if scan[z] = 0 then
-- start of above/below strip
                    ok = 1
                    for i = 1 to length(stack) do
                        if stack[i][1][2] = testp[2] then
                            if testp[1] >= stack[i][1][1]
                            and testp[1] < stack[i][1][1] + stack[i][2]
then
-- this strip has already been scanned
                                ok = 0
                                exit
                            end if
                        end if
                    end for
                    if ok then
-- remember it for later
                        stack = append(stack, {testp, 1})
                        end if
                        scan[z] = 1
                    end if
                elsif scan[z] = 1 then
-- end of above/below strip
                    scan[z] = 0
                end if
            end for
            p[1] = p[1] + 1
        end while
        stack[index][2] = p[1] - stack[index][1][1]
        index = index + 1
    end while
    if atom(tile) then
-- pixels
        for i = 1 to length(stack) do
            pixel(repeat(tile, stack[i][2]), stack[i][1])
        end for
    else
-- tile image
        for i = 1 to length(stack) do
            for x = stack[i][1][1] to stack[i][1][1] + stack[i][2] - 1
do
                pixel(tile[1+remainder(stack[i][1][2],
length(tile))][1+remainder(x, length(tile[1]))], {x,stack[i][1][2]})
            end for
        end for
    end if
end procedure


procedure fill(object tile, sequence p, integer targ)
-- replaces all occurences of targ colored adjacent pixels starting at
some point p
-- tile may be an atom for a solid color
--  or a 2-d sequence of pixels to be tiled
    sequence stack, testp, scan
    integer index, ok
    stack = {{p, 0}}
    index = 1
    while index <= length(stack) do
        p = stack[index][1]
-- scoot all the way to the left
        while get_pixel(p-{1,0}) = targ do
            p[1] = p[1] - 1
        end while
        stack[index][1] = p
-- set flags
        scan = {0,0}
-- scan across current line of target color
        while get_pixel(p) = targ do
-- look for target color above/below current pixel
            for z = 1 to 2 do
                testp = p - {0, 3 - 2 * z}
                if (get_pixel(testp) = targ) then
                    if scan[z] = 0 then
-- start of above/below strip
                    ok = 1
                    for i = 1 to length(stack) do
                        if stack[i][1][2] = testp[2] then
                            if testp[1] >= stack[i][1][1]
                            and testp[1] < stack[i][1][1] + stack[i][2]
then
-- this strip has already been scanned
                                ok = 0
                                exit
                            end if
                        end if
                    end for
                    if ok then
-- remember it for later
                        stack = append(stack, {testp, 1})
                        end if
                        scan[z] = 1
                    end if
                elsif scan[z] = 1 then
-- end of above/below strip
                    scan[z] = 0
                end if
            end for
            p[1] = p[1] + 1
        end while
        stack[index][2] = p[1] - stack[index][1][1]
        index = index + 1
    end while
    if atom(tile) then
-- pixels
        for i = 1 to length(stack) do
            pixel(repeat(tile, stack[i][2]), stack[i][1])
        end for
    else
-- tile image
        for i = 1 to length(stack) do
            for x = stack[i][1][1] to stack[i][1][1] + stack[i][2] - 1
do
                pixel(tile[1+remainder(stack[i][1][2],
length(tile))][1+remainder(x, length(tile[1]))], {x,stack[i][1][2]})
            end for
        end for
    end if
end procedure

-- demonstration code
include graphics.e

if graphics_mode(19) then
end if

ellipse(5, 1, {10,10},{50,50})
ellipse(5, 1, {50,10},{190,50})
ellipse(5, 1, {10,50},{50,190})
ellipse(6, 1, {50,50},{190,190})

-- yellow '/' on green fill
fill({{2,2,14},{2,14,2},{14,2,2}}, {35,35}, 5)
-- white '\' on blue paint
paint({{15,1,1,1},{1,15,1,1},{1,1,15,1},{1,1,1,15}}, {35,35}, 0)

--- code ends ---

Enjoy!

Pete Eberlein <xseal at harborside.com>