Yet another question, Scroll bars

[RobbeK]

Hi all,

Is it possible to put some scroll bars on a Canvas / TBGL window (or do I have to create a separate form for it ?).
I need to look into a very wide BMP at pixel level (math related)

Thanks in advance ,

Rob

[Petr Schreiber]

Hi Rob,

the easiest way to achieve this is to use concept of viewports. You can nest dialog into dialog this way.

So you will have one main dialog, and one secondary, while the secondary will contain just the CANVAS/TBGL surface.

There are some examples in SampleScripts, but I crafted a simpler one here for you:

Uses "UI"

' -- ID numbers of controls
Begin ControlID
  %Main_Viewport
End ControlID    

Begin Const
  %MAIN_WIDTH   = 320
  %MAIN_HEIGHT  = 240
End Const

' -- Create dialog here
Function TBMain()
  Local hDlg As DWord
  Local hViewport As DWord
  
  Dialog New Pixels, 0, "Minimalistic viewport demo",-1,-1, %MAIN_WIDTH, %MAIN_HEIGHT, _
                %WS_POPUP Or %WS_VISIBLE Or %WS_CAPTION Or %WS_SYSMENU Or %WS_MINIMIZEBOX To hDlg
  
  ' -- Place controls here
  hViewport = Control Add VIEWPORT, hDlg, %Main_Viewport, "", 10, 10, %MAIN_WIDTH-20, %MAIN_HEIGHT-20
  Dialog_WithCanvas(hViewport)
 
  Dialog Show Modal hDlg, Call cbDialog

End Function

' -- Callback for main dialog
CallBack Function cbDialog()

  ' -- Test for messages
  Select Case CBMSG

    Case %WM_INITDIALOG
    ' -- Put code to be executed after dialog creation here

    Case %WM_COMMAND
    ' -- You can handle controls here

    Case %WM_CLOSE
    ' -- Put code to be executed before dialog end here

  End Select

End Function
 
Begin ControlID
  %Viewport_Canvas
End ControlID    
 
'----------------------------------------------------------------------------

Function Dialog_WithCanvas(hViewPort As DWord)

  Local hDlg    As Long

  Dialog New Pixels, hViewPort, "", 0, 0, 500, 500, %WS_CHILD Or %WS_CLIPCHILDREN To hDlg

  Control Add Canvas , hDlg, %Viewport_Canvas, "", 0, 0, 500, 500
  Canvas_Attach(hDlg, %Viewport_Canvas, TRUE)
    Canvas_Clear(%BLACK)
    Canvas_Line((0,0), (500, 500), %GREEN)
    Canvas_Line((500,0), (0, 500), %GREEN)
  Canvas_Redraw
  
  Dialog Show Modeless hDlg, Call cbCanvasDialog

  ViewPort_SetChild(hViewPort, hDlg, FALSE )
  
  Function = hDlg
End Function

' -- Callback for canvas dialog
CallBack Function cbCanvasDialog()

  ' -- Test for messages
  Select Case CBMSG

    Case %WM_INITDIALOG
    ' -- Put code to be executed after dialog creation here

    Case %WM_COMMAND
    ' -- You can handle controls here

    Case %WM_CLOSE
    ' -- Put code to be executed before dialog end here

  End Select

End Function

Petr

[RobbeK]

Thanks alot , Petr .... perfect !