Re: MS Windows double buffering

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> Emacs is being tested on X much more than on MS-Windows, and people
> who use it on X tend to be more knowledgeable about the technical
> issues than a typical user of Emacs on Windows.  Moreover, the level
> of expertise we have on our team about Windows-specific GUI aspects is
> significantly lower than in the X case.
>
> So having such a debugging device for significant changes in display
> code is beneficial.

Thanks for clarifying.

> So you are saying this code didn't work correctly before?  Or am I
> misunderstanding something?

No, it was a misunderstanding on my part.  Sorry for the noise.

> This still flickers considerably here, albeit with a significantly
> lower frequency.

What if you comment out these lines in w32term.c?

      if (f && !w32_disable_double_buffering
          && FRAME_OUTPUT_DATA (f)->paint_buffer_dirty
          && !f->garbaged && ignore_dirty_back_buffer)
        w32_show_back_buffer (f);

> What other test cases in the discussions would you recommend to try?

  (run-hooks 'xref-after-jump-hook)

for example, which causes considerable flickering without double
buffering, but none at all when double buffering is enabled.