[RESOLVED] Font Size in MM

[DanDanDan1]

Hello,

I have a strange problem which I am really struggling with, im making a type of CAD program which the user needs to specify a font size in mm.

Everything seems to work ok but when I get the bounding box of the font it reports it as being less than the font height specified. I have pasted the code below. I hope someone here could help me.

Using G As Graphics = PictureBox1.CreateGraphics
 
            G.PageUnit = GraphicsUnit.Millimeter
            G.InterpolationMode = InterpolationMode.HighQualityBicubic
 
            DPI = G.DpiY
            Dim emSize As Single = txtHeight.Text.Replace("mm", "")
 
 
            Using myPath2 As New GraphicsPath
                Dim DrawPoint As PointF = New PointF(4, 5)
                Dim myStringFormat As StringFormat = New StringFormat()
 
                myPath2.AddString(txtText.Text, fntFont.Font.FontFamily, fntFont.Font.Style, emSize, DrawPoint, myStringFormat)
 
                'Get all points
                PointsArr.AddRange(myPath2.PathData.Points)
                'Draw the text using coords
 
                If loadXY5 = True Then
                    myPath2.AddLines(XY5Points.ToArray)
                Else
                    myPath2.AddLines(PointsArr.ToArray)
                End If
 
                boundRect = myPath2.GetBounds()
 
                PictureBox1.Invalidate()
 
            End Using
 
        End Using
 
lblBlankSize.Text = "Blank Size:- " & Math.Round(boundRect.Width) & " X " & Math.Round(boundRect.Height)

[dbasnett]

0.3514 mm per point I think.

[DanDanDan1]

but if pageunit is set to mm surely i can just enter the size as mm??

[DanDanDan1]

Anyone got any ideas?

[boops boops]

Anyone got any ideas?

Yes. It's due to the miter setting. GraphicsPath.GetBounds returns a "loose fit" because the corners of the path could conceivably stick out a long way at sharp bends. I think you can fix it either by specifying the Pen parameter to a value of 1 (or less?); or by setting Path.Flatten to a low value, something like 0.01.

BB

[boops boops]

Here's the correct way to do it:

Using pn As New Pen(Color.Black, 1) With {.MiterLimit = 1}
            boundRectF = myPath2.GetBounds(New Drawing2D.Matrix, pn)
        End Using

The default value for MiterLimit is 10, which results in the actual bounds being inflated by 10 x the (default) Pen width all round.

BB

[DanDanDan1]

Thanks alot but have now sorted this using a different method.