Picture Box Problem

Hi All,

I want to create a small app that displays GPS position according NMEA GPS input.  The input side I'm ok with.  However mapping is a problem.  I have so far...

one picturebox which i load with a bitmap map.  I set scalemode to 0 and scale properties according to known lat long.  whne i move my cursor over the map and show xy correct lon,lat is shown fine.

Next i want to be able to zoom and pan the image.  So i select an area proportional to the picturebox size (1/8) according to where the user clicks on the image. Then i use the paintpicture method to copy this to another picturebox where it is displayed as expected.

Now the problem area.  When the area is displayed in the second pic box(the pic box the user will see) i need to keep the scaleheight width etc according to where the selection area fits on pic box 1.  When I do this I just get a copy of the original image in pic 2??

I have tried copying the cropped image to an imagebox and scaling this accordingly but with no joy?

I need to keep a master image in picturebox 1 as this will be constantly be updated with new points showing current position.  The user must work in another window that will zoom and pan around this master image.

Any help suggestions greatly appreciated.

Thanks in advance,

J

Code as follows:


Dim mouse_xup As Double
Dim mouse_yup As Double
Dim mouse_xdown  As Double
Dim mouse_ydown  As Double
Dim zoomwidth As Double
Dim zoomheight As Double


Private Sub Form_Load()

    Dim zoompic As SuperPicCtl

    Picture2.ScaleMode = 0
    Picture1.ScaleMode = 0
    Picture1.Picture = LoadPicture("C:\TEMP\drive1.bmp")
    Picture1.Picture = Picture1.Image
 
    Picture2.Width = Picture1.Width
    Picture2.Height = Picture1.Height
   
    Picture1.ScaleHeight = -Picture1.Height 'latdegreedelta
    Picture1.ScaleWidth = Picture1.Width 'londegreedelta

    Picture1.ScaleLeft = 0 'minlon
    Picture1.ScaleTop = Picture1.Height 'max lat
   
    Picture2.ScaleHeight = -Picture1.Height 'latdegreedelta
    Picture2.ScaleWidth = Picture1.Width 'londegreedelta

    Picture2.ScaleLeft = 0 'minlon
    Picture2.ScaleTop = Picture1.Height 'max lat

    zoomwidth = Abs(Picture1.ScaleWidth / 4)
    zoomheight = Abs(Picture1.ScaleHeight / 4)

End Sub


Private Sub Picture1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)

    If Toolbar1.Buttons(4).Value = 1 Then

    ElseIf Toolbar1.Buttons(2).Value = 1 Then
    'IF I UNCOMMENT THIS BLOCK I GET A COPY OF ORIG PIC, IF COMMENTED JUST THE CROP AREA IN BOT LEFT PIC2
'        Picture2.ScaleHeight = -zoomheight 'latdegreedelta
'        Picture2.ScaleWidth = zoomwidth 'londegreedelta
'        Picture2.ScaleLeft = X 'minlon
'        Picture2.ScaleTop = Y + zoomheight 'max lat
   
        mouse_xdown = X
        mouse_ydown = Y
               
        Call Picture2.PaintPicture(Picture1, X, Y, zoomwidth, zoomheight, X, Y, zoomwidth, zoomheight)

    End If
End Sub