GNU bug report logs - #37752
Scaling factor inconsistencies between X with and without GTK

Previous Next

Full log

View this message in rfc822 format

From: Carlos Pita <carlosjosepita <at> gmail.com>
To: 37752 <at> debbugs.gnu.org
Subject: bug#37752: Scaling factor inconsistencies between X with and without GTK
Date: Mon, 14 Oct 2019 21:21:54 -0300

In many places in xterm.c you have code like:

#ifdef USE_GTK
  scale = xg_get_scale (f);
#endif

Sometimes scale is only used in GTK specific code and that's ok.

But sometimes it's used in code that's not particular to GTK, for example:

int scale = 1;
#ifdef USE_GTK
  scale = xg_get_scale (f);
#endif
FRAME_CR_SURFACE (f) =
    cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
      scale * FRAME_PIXEL_WIDTH (f),
      scale * FRAME_PIXEL_HEIGHT (f));

Besides, there is x_get_scale_factor, also defined in xterm.c, which
computes the scaling factor in a GTK-independent way, and also
discriminates between x and y scaling factors. It's only used by
x_draw_underwave.

I would like to abstract both cases inside x_get_scale_factor, that
would then use xg_get_scale if in GTK or compute just one scaling
factor (for x or for y) otherwise. Notice that given that the scaling
factor is the ratio of the effective resolution to a base resolution
of 96 dpi *truncated down* to the nearest integer, AFAICS it's almost
impossible to get different scaling factors for x and for y.

What do you think?

Best regards
--
Carlos

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.