Error

# Area of a region choosen with the FREEHAND on the toolbar

#1 Posted : Thursday, January 25, 2007 1:13:12 AM(UTC)

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Posts: 7

Dear all,

Is it possible to misure the area of a region choosen by the user on the freehand (VB6)?

I am trying on the onAnnDrawn  event calling the getarea method, but his gives me the number of pixels that make nosense when I translate them to other misurements

Is it correct what i am trying to do, is there any other way to do it?

Private Sub RasterAnn_OnAnnDrawn(ByVal hAnnObject As Long)

If etiqueta = ANNTOOL_FREEHAND Then MsgBox "Area:" & RasterAnn.AnnGetArea(hAnnObject)
End Sub

#2 Posted : Friday, January 26, 2007 2:24:57 AM(UTC)

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Posts: 7

Hi, its me again, I think my question is not clear, once I get the area, the number of pixels, do I have to calculate the resolution and divide it by the resolution?, can you give me an example of how to calculate the area in Cm once I have the number of pixel

Thanks so much

#3 Posted : Sunday, January 28, 2007 5:12:48 AM(UTC)

Qasem Lubani

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Posts: 3,022

Was thanked: 2 time(s) in 2 post(s)

You can use the following approach to calculate the area in CM:

1-Total area in pixels (Dots) = (Dot *Dot) =Dot ².
2-Resolution is measured in Dot/Inch.
3-Dot²/(XResolution *YResolution) =Inch²
4-Inch² *(2.54 CM/Inch)² =CM²

So, Area in CM² = (Area in Pixel²)/(XResolution *YResolution) * (2.54)²

#4 Posted : Sunday, January 28, 2007 11:19:49 PM(UTC)

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Posts: 7

Thank you very much for your quick response!!!, I will use your formula

Thanks again

Teresa

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