GetDialogBaseUnits

Overview

Group

Quick Info

Windows NT
Yes
Win95
Yes
Win32s
Yes
Import Library
user32.lib
Header File
winuser.h
Unicode
No
Platform Notes
None

The GetDialogBaseUnits function returns the dialog box base units used by Windows to create dialog boxes. Both Windows and applications use these units to convert the width and height of dialog boxes and controls from dialog units, as given in dialog box templates, to pixels, and vice versa.

LONG GetDialogBaseUnits(VOID)

Parameters
This function has no parameters.

Return Values
The return value is a 32-bit value that contains the dialog base units. The low-order word of the return value contains the horizontal dialog box base unit, and the high-order word contains the vertical dialog box base unit.

Remarks
The horizontal base unit is equal to the average width, in pixels, of the characters in the system font; the vertical base unit is equal to the height, in pixels, of the font. Furthermore, each horizontal base unit is equal to 4 horizontal dialog units; each vertical base unit is equal to 8 vertical dialog units. Therefore, to convert dialog units to pixels, an application applies the following formulas:

pixelX = (dialogunitX * baseunitX) / 4

pixelY = (dialogunitY * baseunitY) / 8

Similarly, to convert from pixels to dialog units, an application applies the following formulas:

dialogunitX = (pixelX * 4) / baseunitX

dialogunitY = (pixelY * 8) / baseunitY

The multiplication is performed before the division to avoid rounding problems if base units are not divisible by 4 or 8.