Initial scaling factor

WTSupported in traditional Synergy on Windows




APP_SCALE controls the initial scaling factor for the application.


The application scaling factor as a percentage. The value can be specified as either a whole number or with fractional precision (e.g., 176 or 50.95). The default is 100 (no scaling).


APP_SCALE affects the height and width of the application display screen, the windows for the application, and the characters in those windows. For example, an APP_SCALE value of 200 increases the height and the width of these items by 200%. Note, however, that characters don’t always scale evenly. Characters are sized as large as possible without exceeding the specified percentage in either direction. The maximum value for APP_SCALE is the maximum value of double (1.7*10^308).

You can also alter an application’s scaling programmatically using the %U_WNDFONT(D_SETSCALE) function, or by user action if SYN_RESIZE_SCALE is set in the environment.

For best results when scaling, we recommend using only TrueType or OpenType fonts. Note that message boxes, menu bars and toolbars, buttons, ActiveX controls, and Windows common controls (e.g., Choose Color dialog, Choose Font dialog, Select Palette dialog, Open File dialog, Print Preview, etc.) will not scale.

Setting location

The [synergy], [dbr], or [myprog] section of synergy.ini or synuser.ini (where myprog is any .dbr file).

Used by

UI Toolkit, Synergy windowing API.


In the synergy.ini file,