how to disable gathering Display dimensions in xorg 7.3

Nicolas Mailhot nicolas.mailhot at
Mon Mar 10 12:00:45 PDT 2008

Le lundi 10 mars 2008 à 11:09 -0400, Alek Uritsky a écrit :
> I can manually change the font size on a specific display and make it look 
> good.
> My problem is this:
> my application is running on many linux boxes with displays of different 
> sizes used.
> I cannot know in advance what display size is used and I cannot come to 
> every location and adjust it manually. I understand that new Xorg is doing a 
> better job in adjusting fonts to the actual display size. Here is my 
> question: how would the creators of the new Xorg approach the problem that I 
> face, which is making fonts looking proper without knowing the display size 
> in advance? 

The new xorg is not making fonts look less proper than the previous one.
The new xorg actually does what you ask it, that is to display a font at
foo pt if you ask it a foo pt size. Since pt is a physical unit it needs
the displaysize variable to convert sizes in pt to sizes in pixels (this
is what old xorg got wrong it assumed a fixed conversion ratio which is
obviously not the case given hardware variability)

If for whatever reason you want your fonts to have a fixed pixel size
the solution is not to try to wedge the pt>px conversion factor to
reproduce the old xorg misbehaviour the solution is to request font
sizes in pixels in your app.

This also makes plain the shortcomings of that approach: if your app
thinks in pixels any hardware with pixels of a size significantly
different from what you assumed will break your app.

In contrast the new xorg will let you use hardware with high pixel
density without the text degenerating in fly droppings.

If for whatever reason you want your fonts to be sized a fixed % of the
total screen size you need to ask X for the current resolution in
pixels, convert your % to a pixel value and use this pixel value in font

You complain that the new xorg produces small fonts on a big display,
but you should be aware than the old xorg would have produced small or
big fonts depending on how far the user hardware was from your
assumptions. That it didn't on the few displays you tested only proved
your hardware sample was overly homogeneous.

Barring bugs the new xorg will always produce text of the same physical
size regardless of the hardware the user is using.

Nicolas Mailhot
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