Problem with DRAW or my "scanning" routine?

[TempodiBasic]

SOLVED again , now saving the feature of  drawing only foregorund colors of the image

please play the code and comments let understand where and why the issue arises

Code: (Select All)

Rem 27 06 2023 / 28 06 2023  SOLVED saving the feature of drawing only foreground of image
Rem but James D Jarvis  wants to draw only foreground of image, NO background like for a vector image
'***************************************************************
'scanning a section of the screen converting and writing it with DRAW
'why doesn't it work?
'***************************************************************
Screen _NewImage(480, 400, 256)
$Console
_Console Off
Randomize Timer
Cls
_PrintMode _KeepBackground
_PrintString (0, 0), "AB"
'Line (1, 1)-(1, 14), 15
_Delay 0.5
msg$ = "<-- scanning this as a sample image"
_PrintString (40, 0), msg$
x = 0: y = 0
dd$ = ""
wid = 16
ht = 16
Draw "s4"
dd$ = Scan_draw$(x, y, ht, wid)
_Delay 1
Locate 4, 4
Line (40, 0)-(40 + Len(msg$) * 8, 15), 0, BF
msg$ = "ready (press any key)"
_PrintString (0, 100), msg$

Sleep
Line (0, 100)-(Len(msg$) * 8, 115), 0, BF
Locate 4, 4
Print "Draw Scanned image, Why isn't it drawing correctly?"
Print "Is the problem in the scanning routine or in how draw functions?"
Print "it is a problem arising from the translation of scanned data into Draw commands!"
putdraw 50, 0, dd$
putdraw 1, 20, dd$
drawto_console dd$
Input alldone$
End
'***************************************************************
' subroutines for making use of draw strings in 256 color mode.
' color 0 is treated as transpaernt
Sub putdraw (xx, yy, dd$)
    Draw "bm" + Str$(xx) + "," + Str$(yy) + dd$
End Sub
Sub drawto_console (dd$)
    'program must have console output activated earlier
    'prints the string in a clean console window so it may be copied and pasted on any system with console support
    sd& = _Dest
    _Console On
    _Dest _Console
    Cls
    Print dd$
    Print
    Print "Copy and Paste the above text for future use in DRAW commands"
    _Dest sd&
End Sub
Function Scan_draw$ (sx, sy, ht, wid)
    'scan a screen area starting at point sx,sy and saving it to the string DD$ for use in later draw commands
    'simply scans each row and tracks color changes
    For y = 0 To ht - 1
        x = 0
        Do
            klr = Point(sx + x, sy + y) 'here cohordinates are relative to topleft starter point  sx,sy
            n = -1 ' why do you need to start from -1? So you are including also n = 0 that is the same point valutated here above
            Do
                n = n + 1
                nklr = Point(x + n, y) 'here cohordinates are absolute starting from topleft starter point 0,0
            Loop Until nklr <> klr Or x + n >= wid
            'n, going out of loop, is bringing the value of the next color    or got right edge
            If klr = 0 Then
                dd$ = dd$ + "br" + _Trim$(Str$(n)) ' it moves blind the graphic cursor towards the right edge  with step of 2 pixels ata a time
            Else
                ' R draws the starting point + the n pixels, so to solve we go back 1 pixel, then we draw n-1 pixels and then we go forwards 2 pixels
                dd$ = dd$ + "bm-1,+0" + "C" + _Trim$(Str$(klr)) + " " + "R" + _Trim$(Str$(n - 1)) + "bm+2,+0" ' it draws a line to right from the starter point
            End If
            x = x + n
        Loop Until x >= wid
        dd$ = dd$ + "bd1bl" + Str$(wid) ' here it moves the graphic cursor to the first point of the next row
    Next y
    Scan_draw$ = dd$
End Function

Short version for who has no time to read code and code comments:
Commands of DRAW draw from the starting point of the screen towards the direction selected of N times (if S4 each n = 1 pixel)
So if you type DRAW "s4c15 r1" it draws 5 pixels to right 1 of starting position + 4 of movement towards right edge of image/screen.
As you understand you are not able to draw a single pixel until you do not use M command that uses absolute/relative cohordinates and let move also 1 pixel towards the choosen direction.