Re: [Devel] TrueType font-scaling

[Owen Taylor]

Vadim Plessky <address@hidden> writes:

> |  OK, I think I need to alias address@hidden to
> |  foot-in-mouth-list ;-), seem to always make mistakes when posting
> |  here... I (for some reason) thought I was replying to a post
> |  about the current Red Hat beta, which does behave as above.
> |
> |  Most Linux setups will either use the physical screen resolution
> |  (for Xft) or a fixed value of 75 or 100dpi (for rendering via the
> |  core  X protocol)
> 
> Hi Owen!
> 
> AFAIK several graphics adapters supported under XFree86 (ATI and Matrox, in 
> particular) can auto-detect dpi during initialization / X startup.
> So, there is no need to pre-define 96dpi if user has modern graphics adapter.

A) It's very hard to tell _if_ the resolution was probed successfully,
   and the default of XFree86 (75dpi, I think) is too low. Also,
   sometimes the DPI will be "probed" but be wrong... we've seen cases 
   where cards will probe at 12  x 9dpi and things like that.

B) My conclusion was eventually that matching the physical screen 
   resolution is just wrong. Very few people care about how
   many inches tall letters are on their screen. They care about:

    - Angular size of the letters (think handheld or projector)
    - If pixels are visible, how many pixels are in each letter

   (Seee http://www.xfree86.org/pipermail/fonts/2002-June/001771.htmlm
   for some detailed discussion of the issue by Keith Packard.)

C) Unless padding and graphics scale along with the text, large
   changes in the DPI used will destroy layouts.

Regards,
                                        Owen