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How to calculate twips to pixels

Usefull Functions & Procedures

How to calculate twips to pixels

by  Mike Gagnon  Posted    (Edited  )
Twips is a unit of measure sometimes used in calculating picture resolution.

Code: 
#DEFINE TWIPS_IN_CM 567
#DEFINE HWND_DESKTOP 0
#DEFINE LOGPIXELSX 88
#DEFINE LOGPIXELSY 90

?TwipsToMM(5300)
?TwipsPerPixelX()
?TwipsPerPixelY()

FUNCTION TwipsToMM
 LPARAMETER tnTwips
 RETURN INT(((tnTwips + 0.0005) / TWIPS_IN_CM) * 10)
ENDFUNC

FUNCTION TwipsPerPixelX
 LOCAL lnDC, lnTwipsPerpixelX
 DECLARE LONG GetDC IN "user32" LONG hwnd
 DECLARE LONG ReleaseDC IN "user32" LONG hwnd, LONG hdc
 DECLARE LONG GetDeviceCaps IN "gdi32" LONG hdc, LONG nIndex
 lnDC = GetDC(HWND_DESKTOP)
 lnTwipsPerpixelX = 1440 / GetDeviceCaps(lnDC, LOGPIXELSX)
 ReleaseDC(HWND_DESKTOP, lnDC)
 RETURN lnTwipsPerpixelX
ENDFUNC

FUNCTION TwipsPerPixelY
 LOCAL lnDC
 DECLARE LONG GetDC IN "user32" LONG hwnd
 DECLARE LONG ReleaseDC IN "user32" LONG hwnd, LONG hdc
 DECLARE LONG GetDeviceCaps IN "gdi32" LONG hdc, LONG nIndex
 lnDC = GetDC(HWND_DESKTOP)
 lnTwipsInPixelY = 1440 / GetDeviceCaps(lnDC, LOGPIXELSY)
 ReleaseDC(HWND_DESKTOP, lnDC)
 RETURN lnTwipsInPixelY
ENDFUNC
Mike Gagnon
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