You can use GetDeviceCaps() to get Pixels per Cm as shown below.

CLEAR 

#DEFINE LOGPIXELSX 88    && Logical pixels/inch in X         
#DEFINE LOGPIXELSY 90    && Logical pixels/inch in Y         

DECLARE INTEGER GetActiveWindow IN WIN32API
DECLARE INTEGER GetDC IN WIN32API INTEGER hDC
DECLARE INTEGER GetDeviceCaps IN WIN32API INTEGER hDC, INTEGER nIndex

* Active window handle
lnHwnd = GetActiveWindow()
* Device context
lnHDC = GetDC(lnHwnd)

* Pixels per Inch
lnPixelsPerInchX = GetDeviceCaps(lnHDC, LOGPIXELSX)
lnPixelsPerInchY = GetDeviceCaps(lnHDC, LOGPIXELSY)
* Pixels per cm
lnCmPerInc = 2.54
lnPixelsPerCmX = lnPixelsPerInchX / lnCmPerInc
lnPixelsPerCmY = lnPixelsPerInchY / lnCmPerInc

? lnPixelsPerCmX, lnPixelsPerCmY

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>
>How transform "Top" or "left" Value into other value ( cm ) ?
>
>here for Top = 6 , i want 1,1 cm ...
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>http://cjoint.com/data/lbxxfYMzm4.htm
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>Thank in advance for help.
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>
>bernhart