Steema Central

Posted: **Tue Jul 24, 2007 8:27 pm**

Using TChart ActiveX 7.0.1.4

I've found that using the following VB code doesn't show the gradient for the left wall, instead it is transparent.

If you set Canvas.UseBuffer to True, or you set the viewport and window extent to the same thing, then it works, otherwise it doesn't. TChart seems to be not respecting the mapping mode for the device context when drawing the gradients for the walls.

Is there a workaround to make this work under these conditions? Or is this just a bug that will have to be fixed?

Code: Select all

Option Explicit

Private Type POINTAPI
        x As Long
        y As Long
End Type
Private Type size
        CX As Long
        CY As Long
End Type

Private Declare Function SetMapMode Lib "gdi32" (ByVal hdc As Long, _
      ByVal nMapMode As Integer) As Integer

Private Declare Function SetViewportExtEx Lib "gdi32" _
  (ByVal hdc As Long, ByVal nX As Long, ByVal nY As Long, _
  lpSize As size) As Long
Private Declare Function SetViewportOrgEx Lib "gdi32" _
  (ByVal hdc As Long, ByVal nX As Long, ByVal nY As Long, _
  lpPoint As POINTAPI) As Long
Private Declare Function SetWindowExtEx Lib "gdi32" _
  (ByVal hdc As Long, ByVal nX As Long, ByVal nY As Long, _
  lpSize As size) As Long
Private Declare Function SetWindowOrgEx Lib "gdi32" _
  (ByVal hdc As Long, ByVal nX As Long, ByVal nY As Long, _
  lpPoint As POINTAPI) As Long
  
Dim tchart1 As TChart

Dim nX As Integer
Dim nY As Integer


Private Sub Form_Load()

    Set tchart1 = CreateObject("TeeChart.TChart")
    
    tchart1.AutoRepaint = False
    tchart1.Canvas.UseBuffer = False
    
    With tchart1.Walls.Left.Gradient
        .Visible = True
        .StartColor = RGB(255, 0, 0)
        .EndColor = RGB(0, 255, 0)
    End With
    
    With tchart1.Panel.Gradient
        .Visible = True
        .StartColor = RGB(0, 0, 255)
        .EndColor = RGB(255, 0, 255)
        .Direction = gdDiagonalUp
    End With
          
    Dim lpPoint As POINTAPI
    Dim lpSize As size
    
    nX = 400
    nY = 400
    
    SetMapMode Me.hdc, 7
    SetViewportOrgEx Me.hdc, 0, 0, lpPoint
    SetWindowOrgEx Me.hdc, 0, 0, lpPoint
    SetViewportExtEx Me.hdc, nX, nY, lpSize
    SetWindowExtEx Me.hdc, nX * 2, nY * 2, lpSize

End Sub

Private Sub Form_Paint()

    tchart1.Draw Me.hdc, 0, 0, nX * 2, nY * 2

End Sub

Posted: **Thu Aug 09, 2007 2:01 pm**

Hi,

yes, we get the same result as you. But we think that if the MapMode is only set to redimension it, as a workaround you could change its size manually, into the Draw method, I've test it here and works fine.

For example :

Code: Select all

....
....
'  commented lines..

 '    SetMapMode Me.hdc, 7
 '    SetViewportOrgEx Me.hdc, 0, 0, lpPoint
 '    SetWindowOrgEx Me.hdc, 0, 0, lpPoint
 '    SetViewportExtEx Me.hdc, nX, nY, lpSize
 '    SetWindowExtEx Me.hdc, nX * 2, nY * 2, lpSize   
End Sub

Private Sub Form_Paint()
    TChart1.Draw Me.hdc, 0, 0, nX / 2, nY * 2
End Sub

Posted: **Thu Aug 09, 2007 5:07 pm**

Okay, cool. In our case the map mode is needed, as changing the viewport and window sizes is how we accomplish zooming in our app.

Thanks anyways.

Steema Central

Gradients on Walls, not using the canvas buffer, and Draw()

Gradients on Walls, not using the canvas buffer, and Draw()