mozilla misreads dpi when using Xinerama




17 years ago
14 years ago


(Reporter: Morten Nilsen, Assigned: Marc Attinasi)



Firefox Tracking Flags

(Not tracked)



(2 attachments)



17 years ago
I'm using xinerama on my XFree86 4.1.0 server...
one screen is at 1600x1200 and the other 1152x768
I have set the dpi in XF86Config...

xdpyinfo tells me:

screen #0:
  dimensions:    2752x1200 pixels (363x277 millimeters)
  resolution:    193x110 dots per inch

the monitors in XFree86Config:
Section "Monitor"
        Identifier   "Display 1"
        DisplaySize  360 275
        HorizSync    31.5 - 90.0
        VertRefresh  50.0 - 90.0

Section "Monitor"
        Identifier   "Display 2"
        DisplaySize  325 240
        HorizSync    31.5 - 90.0
        VertRefresh  50.0 - 90.0

removing the second monitor from my setup and disabling xinerama fixes this
issue... so it's a xinerama specific issue it seems.

Comment 1

17 years ago
Can you please attach the output of "xdpyinfo" ?

Comment 2

17 years ago
Created attachment 65015 [details]
xdpyinfo output

Comment 3

17 years ago
Per xdpyinfo output your screen resolution is
-- snip --
resolution:  193x110 dots per inch
-- snip --

I assume this is a Xserver misconfiguration. Wanna try the "-dpi" option (e.g. X
:1 -dpi 90) ?

Comment 4

17 years ago
I allready said xdpyinfo reported 193x110dpi...
but this is infact the _correct_ dpi for screen 0

attaching my XF86Config too

Comment 5

17 years ago
Created attachment 65020 [details]

Comment 6

17 years ago
OK, that means you _WANT_ a resolution of 193x110dpi in your Xserver - but
Mozilla does not honor these values ?

Comment 7

17 years ago
yes. that's right. I want that dpi...
but mozilla misreads it, and no other apps do.

but not all the text is misrepresented...
only my <table> with css 10pt monospace; font.
that font gets about twice the size of the other normal text.
which hasn't got any css specified fonts at all
Morten, what build are you using?  This looks a lot like bug 104576

Comment 9

17 years ago
CVS tip

Comment 10

17 years ago
bug 104576 does look related...
except I compile with --enable-xinerama

Comment 11

17 years ago
In fact, backing out the patch for bug 104576 locally fixes this bug.
well.... I have to say that it sounds like your X server is just confused about
its dpi.  193x110 is a pretty bogus value...

ccing people who know about bug 104576

Comment 13

17 years ago
193x110 dpi isn't a bodus value, as the actual size of my screen (spanning two
separate monitors) does have that size...

and if it was bogus, why isn't _any_ other app affected?
'tis is a bug ... but it seems to me 'tis will be a bug for on of two people...
the ones who were fixed by bug 104576, and the ones who were broken from it.

I think the setup I have is correct, and it seems all my programs (except
mozilla) thinks so too :)

I can live with having reversed the patch locally, but if mozilla can be made to
behave nicely in either case... that certainly would be nice :)
> 193x110 dpi isn't a bodus value, as the actual size of my screen (spanning two
> separate monitors) does have that size...

This is not a size.  This is a pixels-per-inch number.  X thinks that the
combined width of your two monitors is 363mm.  The total number of horizontal
pixels is 2752.  Hence the 193dpi number.  I very much doubt that you have two
monitors the sum of whose widths is 36.3cm.  If you do, I withdraw my
classification of your DPI as bogus.  :)

Comment 15

17 years ago
reporter, do you need to specify the DisplaySize in your XF86Config file or are
your monitors not reporting the DDC values? I have run dissimiliar screens just
fine without specifying the size.

Your DPI x and y values should be very close to each other.  If they aren't,
then your screen is drawing rectangles, not equilateral shapes.

Comment 16

17 years ago
hmm... okay then...
but why doesn't this effect my other programs then?
and what should I do to my XF86Config file to make it correct?


17 years ago
Severity: major → normal
Target Milestone: --- → Future

Comment 17

16 years ago
I'm wrong it seems :P
Last Resolved: 16 years ago
Resolution: --- → INVALID

Comment 18

14 years ago
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