How To Determine Font Size Setting

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This article was previously published under Q137556

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SUMMARY

The code in this article demonstrates how to use the Foxtools.fll library commands to call Microsoft Windows application programming interface (API) functions to determine if the current session of Windows is using Small or Large Fonts. The following API functions are used:

GetDC()
GetDeviceCaps()
ReleaseDC()

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MORE INFORMATION

The program first loads the Foxtools.fll library that is supplied with FoxPro for Windows. Then it initializes some variables and retrieves the handle for the display device. Next, it calls the GetDeviceCaps function, requesting the number of pixels per logical inch along the display width and height. If the number of pixels is equal to 96, Windows is running with Small Fonts. If the number of pixels is equal to 120, Windows is running with Large Fonts. The program then releases the handle to the display device and the library.

SET LIBRARY TO SYS(2004) + "FOXTOOLS.FLL" ADDITIVE

* create variables to pass index to GetDeviceCaps()
* this value cane be found in the WINGDI.H file

LOGPIXELSX = 88
LOGPIXELSY = 90

* get the handle to the device context

lnGetDC = RegFN("GetDC","I","I")
lnHDC = CallFN(lnGetDC,0)

* get the number of pixels per logical inch

lnGetLogPix = RegFN("GetDeviceCaps","II","I")
lnLogPixX = CallFN(lnGetLogPix,lnHDC,LOGPIXELSX)
lnLogPixY = CallFN(lnGetLogPix,lnHDC,LOGPIXELSY)

* determine if small or large fonts, either lnLogPixX or
* lnLogPixY may be used to test for the values 96 or 120

IF lnLogPixX < 96
  WAIT WINDOW "Windows is using smaller than Small Fonts"   
ELSE IF InLogPixX = 96
  WAIT WINDOW "Windows is using Small Fonts"   
ELSE IF InLogPixX < 120
  WAIT WINDOW "Windows is using between Small Fonts and Large Fonts"
ELSE IF IF lnLogPixX = 120
  WAIT WINDOW "Windows is using Large Fonts"
ELSE
  WAIT WINDOW "Windows is using larger than Large Fonts"
ENDIF

* release the handle to the device context

lnRelease = RegFN("ReleaseDC","II","I")
= CallFN(lnRelease,0,lnHDC)

* release the FOXTOOLS.FLL library

RELEASE LIBRARY SYS(2004) + "FOXTOOLS.FLL"

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REFERENCES

Microsoft Windows Software Development Kit, "Programmer's Reference, Volume 2: Functions," pages 350-354, 785.

Foxtools.wri located in the C:\Fpw26\Goodies\Foxtools directory.

Wingdi.h located in the C:\C700\Include directory

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