bug#19117: 25.0.50; emacs on x11 chooses different fonts for the same face sometimes

[Dmitry Antipov <dmantipov@yandex.ru>]

On 12/17/2014 09:57 AM, Dima Kogan wrote:

> Apparently the "0 0 0 0" represents a "scalable" font. Not 100% sure
> what this means in the context of X11. In Emacs, we load this font with
> XLoadQueryFont() in xfont_open(). I wrote a small program to see what
> this means on my box:
>
>   #include <stdio.h>
>   #include <stdlib.h>
>   #include <X11/Xlib.h>
>   #include <X11/Xatom.h>
>   int main(void)
>   {
>       Display* dpy = XOpenDisplay(":0.0");
>
>       const char* font_input = "-adobe-courier-medium-i-normal-*-0-0-0-0-p-0-iso8859-1";
>       const char* font_output;
>       unsigned long value;
>
>       XFontStruct *font = XLoadQueryFont(dpy, font_input);
>       XGetFontProperty (font, XA_FONT, &value);
>       font_output = XGetAtomName (dpy, (Atom) value);
>
>       fprintf(stderr, "font '%s' loaded as '%s'\n", font_input, font_output);
>       return 0;
>   }
>
> Here I load the scalable font that Emacs is choosing (and that xlsfonts
> says exists on my machine). Then after it is loaded, I ask what the font
> is called. The output is this:
>
> font '-adobe-courier-medium-i-normal-*-0-0-0-0-p-0-iso8859-1' loaded as
> '-urw-nimbus mono l-regular-o-normal--17-120-100-100-p-100-iso8859-1'

Hm. On my system (Fedora 21), there are no -adobe-courier-medium-i-normal-*
fonts but:

$ xlsfonts | grep -- -adobe-utopia-bold-i-normal-
-adobe-utopia-bold-i-normal--0-0-0-0-p-0-iso10646-1
-adobe-utopia-bold-i-normal--0-0-0-0-p-0-iso10646-1
-adobe-utopia-bold-i-normal--0-0-0-0-p-0-iso8859-1
-adobe-utopia-bold-i-normal--0-0-0-0-p-0-iso8859-1
-adobe-utopia-bold-i-normal--10-100-75-75-p-58-iso10646-1
-adobe-utopia-bold-i-normal--12-120-75-75-p-70-iso10646-1
-adobe-utopia-bold-i-normal--14-100-100-100-p-78-iso10646-1
-adobe-utopia-bold-i-normal--14-100-100-100-p-78-iso8859-1
-adobe-utopia-bold-i-normal--15-140-75-75-p-82-iso10646-1
-adobe-utopia-bold-i-normal--17-120-100-100-p-93-iso10646-1
-adobe-utopia-bold-i-normal--17-120-100-100-p-93-iso8859-1
-adobe-utopia-bold-i-normal--19-140-100-100-p-109-iso10646-1
-adobe-utopia-bold-i-normal--19-140-100-100-p-109-iso8859-1
-adobe-utopia-bold-i-normal--19-180-75-75-p-105-iso10646-1
-adobe-utopia-bold-i-normal--25-180-100-100-p-139-iso10646-1
-adobe-utopia-bold-i-normal--25-180-100-100-p-139-iso8859-1
-adobe-utopia-bold-i-normal--25-240-75-75-p-140-iso10646-1
-adobe-utopia-bold-i-normal--33-240-100-100-p-186-iso10646-1
-adobe-utopia-bold-i-normal--33-240-100-100-p-186-iso8859-1

And running your program with -adobe-utopia-bold-i-normal--0-0-0-0-p-0-iso8859-1
produces:

font '-adobe-utopia-bold-i-normal--0-0-0-0-p-0-iso8859-1' loaded as '-adobe-utopia-bold-i-normal--17-120-100-100-p-94-iso8859-1'

Your X behaves pretty strange; I can't explain this just now.

Also, what happens if you specify default font via ~/.Xdefaults
and run with emacs -q (small 'q', not 'Q')?

Dmitry