These are the valid screen distances, according to the man page for Tk_GetPixelsFromObj, Tk_GetPixels, Tk_GetMMFromObj, Tk_GetScreenMM:
- <none>
- The number specifies a distance in pixels.
- c
- The number specifies a distance in centimeters on the screen.
- i
- The number specifies a distance in inches on the screen.
- m
- The number specifies a distance in millimeters on the screen.
- p
- The number specifies a distance in printer's points (1/72 inch) on the screen.
The above are all suffixes to floating-point numbers. Thus, 5 is five pixels, 5c is five centimetres, and so on.