bug in pgtk rendering

bug in pgtk rendering

[Andrew Cohen]

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I have noticed a persistent rendering bug with pgtk which seems to be
related to multiple monitor use. I am using 2 monitors (primary
3840x2160 at 200% scaling with gnome; secondary 1920x1080 at 100%
scaling). I don't see problems on the primary monitor. But
intermittently on the secondary monitor I see large portions of the
screen with blocky blurred text:


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It comes and goes---re-exposing the window sometimes fixes it, as does
moving the frame to the primary monitor and back; but the distortion
always returns.

I'm happy to do some debugging but don't know exactly where to start. 


-- 
Andrew Cohen

Re: bug in pgtk rendering

[Andrew Cohen]

Sorry for following up on my own post---I was filing a bug report and
realized I haven't tried to reproduce the problem with emacs -Q. I'll do
some more digging before reporting the bug. I apologize for the noise. 

>>>>> "AC" == Andrew Cohen <acohen@ust.hk> writes:

    AC> I have noticed a persistent rendering bug with pgtk which seems
    AC> to be related to multiple monitor use. I am using 2 monitors
    AC> (primary 3840x2160 at 200% scaling with gnome; secondary
    AC> 1920x1080 at 100% scaling). I don't see problems on the primary
    AC> monitor. But intermittently on the secondary monitor I see large
    AC> portions of the screen with blocky blurred text:



    AC> It comes and goes---re-exposing the window sometimes fixes it,
    AC> as does moving the frame to the primary monitor and back; but
    AC> the distortion always returns.

    AC> I'm happy to do some debugging but don't know exactly where to
    AC> start.

    AC> -- Andrew Cohen


-- 
Andrew Cohen

Re: bug in pgtk rendering

[Po Lu]

Andrew Cohen <acohen@ust.hk> writes:

> Sorry for following up on my own post---I was filing a bug report and
> realized I haven't tried to reproduce the problem with emacs -Q. I'll do
> some more digging before reporting the bug. I apologize for the noise. 

It's probably bug#54040.  Could you try the fix I posted at the end of
that thread?  The original reporter went quiet.

Thanks in advance.

Re: bug in pgtk rendering

[Andrew Cohen]

>>>>> "PL" == Po Lu <luangruo@yahoo.com> writes:

    PL> Andrew Cohen <acohen@ust.hk> writes:
    >> Sorry for following up on my own post---I was filing a bug report
    >> and realized I haven't tried to reproduce the problem with emacs
    >> -Q. I'll do some more digging before reporting the bug. I
    >> apologize for the noise.

    PL> It's probably bug#54040.  Could you try the fix I posted at the
    PL> end of that thread?  The original reporter went quiet.

I guess you mean this?

>What happens if you replace:
>
>  scale = gtk_widget_get_scale_factor (FRAME_GTK_WIDGET (f));
>  cairo_surface_set_device_scale (surface, scale, scale);
>
>With:
>
>  cairo_surface_set_device_scale (surface, 1, 1);


That now makes everything blurry on the primary monitor as well as the
secondary, and much more frequently  :(




-- 
Andrew Cohen

Re: bug in pgtk rendering

[Po Lu]

Andrew Cohen <acohen@ust.hk> writes:

> That now makes everything blurry on the primary monitor as well as the
> secondary, and much more frequently  :(

Odd, thanks for testing.  I don't know what else to try, and to make
matters worse I have no high-definition monitor (much less two) to test
on.

But I will keep looking into this.