Why does .GetPathExtents not work? (cCairoContext)

[tmighty2]

In the following code, GetPathExtents never fills the values.

I don't see why.

Thank you for any help!

Public Sub DrawTo(ByRef uDestCC As cCairoContext, ByVal uLeft As Long, ByVal uTop As Long)

    uDestCC.Save

    Dim Matrix_Plan As cCairoMatrix
    Set Matrix_Plan = Cairo.CreateIdentityMatrix

    Dim dblOffx As Double
    Dim dblOffy As Double

    dblOffx = Me.OffsetFactorX * ((m_Img.Width * (Me.ScaleFactorW)) / 2)
    dblOffy = Me.OffsetFactorY * ((m_Img.Height * (Me.ScaleFactorH)) / 2)
    Matrix_Plan.TranslateCoords uLeft + dblOffx, uTop + dblOffy

    ' Apply rotation
    Matrix_Plan.RotateCoordsDeg m_sngAngleDeg

    ' Scale and center the image
    Matrix_Plan.ScaleCoords Me.ScaleFactorW, Me.ScaleFactorH
    Matrix_Plan.TranslateCoords -(m_Img.Width / 2) - (Me.CenterOffsetX / 2), -(m_Img.Height / 2) - (Me.CenterOffsetY / 2)

    Set uDestCC.matrix = Matrix_Plan
    
    Dim x1 As Double
    Dim x2 As Double
    Dim y1 As Double
    Dim y2 As Double
    Dim dw As Double
    Dim dh As Double

    'these values are always 0:
    uDestCC.GetPathExtents x1, y1, x2, y2  '<- retrieve TopLeft- and BottomRight-points of the Bounding-Rect
    dw = Abs(x2 - x1)
    dh = Abs(y2 - y1)
    Debug.Assert dh = 0
    Debug.Assert dw = 0
    
    uDestCC.RenderSurfaceContent m_Img, 0, 0, , , CAIRO_FILTER_BEST, m_dblAlpha
    uDestCC.Restore

    'to check the extents
    DrawRectangle uDestCC, x1, y1, dw, dh, 0, vbRed, 0.2, vbBlack, 1, 1

End Sub

[jpbro]

It doesn't look like you've drawn anything that would generate a path yet. For example, if you put a path "drawing" call right before your GetPathExtents, then values will be filled into the appropriate variables:

uDestCC.Rectangle 100, 200, 600, 500

[tmighty2]

Thank you. The problem with this approach is

1) rotating makes the .GetPathExtents have weird values
2) I seem to be unable to "remove" this rectangle by using .Save / .Restore.

[tmighty2]

I have attached a sample project.
I believe that this problem has not been discussed before.

Can you please have a look?
I can not get rid of the rectangle, and my calculation seems to be just wrong.

When you think "Oh, it does work!", then please check the checkboxes "Animate ScaleFactorW" to see the behaviour.

[tmighty2]

Somebody gave me the answer, and I was able to fix the problem using CopyPath(Flat=true).

[tmighty2]

No, I was wrong. It's not solved yet.

[tmighty2]

But now :-)