Re: patch -- fix resolution in pango (win32 backend)

[Joaquín Cuenca Abela <cuenca pacaterie u-psud fr>]

On Tue, 2002-05-21 at 20:35, Tor Lillqvist wrote:
> Joaquin Cuenca Abela writes:
>  > If you're ready to give a fake dpi for big monitors, why are you
>  > reluctant to give a fake dpi for desktop monitors?
> 
> Because desktop monitors are all viewed at more or less the same
> distance, regardless of size. Huge screens are usually viewed at a
> (much) larger distance. What would be really correct would be to
> specify the viewing angle of the screen. But specifying the width and
> height is equivalent, as long as the viewing distance is
> constant.

ok, I hope then that the argument about users looking at its screen at
about the double of distance than when they look at a sheet of paper
will buy you :-)  I'm not inventing that, btw.  From what I've read, the
typical distance between the user's eyes and a sheet of paper it's
something as a foot, and something as two foots to the screen (I guess
that due to luminosity)

Anyway the real argument to not use real dpi in screen it's not this
one, but a more pragmatic argument: fonts at typical font sizes renders
as shit with currently used resolutions/screens sizes.  If you ask
everybody to use "zoom" to fix this problem, everybody will ask you "why
don't put this zoom in pango in the first place?"

>  > Certainly not.  If you're using a 1900x1200 resolution you will
>  > have buttons, icons, scroll bars, everything with the same number
>  > of pixels, but not with the same size.  Fonts are not an exception.
> 
> Maybe, maybe not. Some might prefer to see the increased pixel amount
> used just for the benefit of smoother font outlines, for instance.

Yes, and it's a noble goal.  Usually these people (I'm included there
when I got my hands on a big screen with a high resolution) changes its
font resolution to 120 dpi to have smoother font outlines, and also
these people is ready to find little problems, as text cuts in dialogs
designed to 96dpi fonts, and a general taste of something unaesthetic
(probably due to not being able to resize all the widgets).

Putting that in pango, removes the possibility from the user to choose
bigger or smaller fonts, other than changing the application, or some
obscure configuration file, read .gtkrc, if possible at all (changing
.gtkrc will only change the font size for menus and dialogs, but not the
font size used internally by the app).  It also makes almost impossible
for the programmer to pick a suitable size for their users.

I agree that it will be nice if you can just change your screen
resolution and have everything with a smooth resolution, but with
current technology you only get a bunch of text that don't knows how to
fit in their boxes...  Scaling font size in pixels without scaling
everything else just don't work.

>  > But nobody expects to have their fonts growing with the resolution,
>  > while everything else remains with the same size.
> 
> (You mean fonts growing in pixels, I assume.)

yes

> So, why is then that a
> Pango font specification has the size *in points*, not in pixels?
> 
> Oh well, I think I am understanding some of your points better
> now. But I still don't see how your arguments are related to using
> those "logical inches" in the Windows API. Or is there a nonlinear
> relationship between the true monitor size and its size in logical
> inches? (Like, if the monitor is 24", Windows might indeed say its
> size is 24 logical inches, but if it is 15", Windows says its size is
> maybe 17 logical inches? Ouch.)

the point to use "logical inches" instead of real ones is that the user
can change what a logical inch is, but not what a real inch is.

Users with bad vision can choose a high logical inch to see better the
fonts, users that want more screen space can choose a low logical inch. 
Default logical inch size is just one size that renders fonts at a
readable size for almost everybody.  With real logical inch fonts render
at a unreadable size for almost everybody.

And no, users with bad vision can not fake their screen size, because
even if possible at all, if they do that they will screw any possible
app that needs to know the real size of the screen.

Even for people with very very high resolutions, with say, a real screen
resolution of 150dpi, fonts at 96dpi are still readable (tiny, but
readable).  The number of pixels that you use to draw the font accounts
much more for the readability of a font than its real size.  Take the
'f' letter, render it with a height of 4 pixels, but with a size of 1
meter per pixel, and you will finish with a nice graphity, but an
absolutely unreadable character.  Draw it with 40 pixels, each one of
them of 1/20 a millimeter, and you will still see a nice tiny 'f'.

The number of pixels that you have to draw a letter it's much more
important than the number of inches of this letter.

Cheers,

-- 
Joaquín Cuenca Abela
cuenca pacaterie u-psud fr