bug#16736: Compiling a Lisp file causes display to flash off and on

[Glenn Morris <rgm@gnu.org>]

Eli Zaretskii wrote:

> sounds like the frame is cleared and completely redrawn, which I won't
> expect during byte-compile, which only redisplays the echo area.  If I
> put a breakpoint in clear_frame, it is never hit during your recipe.

I put a break on x_clear_frame, and with emacs -Q, byte-compile-file on
scheme.el triggers it.

>   (while t
>     (split-window-below)
>     (sit-for 0.05)
>     (delete-other-windows)
>     (sit-for 0.05))
>
> Typing "C-x C-e" at the right paren of this in *scratch*, I see no
> flickering in the tool bar.  Do you?

Oh yes. It looks awful!

In an attempt to follow your instructions, I put a break on dispnew.c:3045.

So far I don't think I am getting any useful information out of this,
because it seems to trigger a lot, and I'm not sure I'm catching it at
the right time. I'll try again later, but frankly I don't know what I'm
doing, even with your detailed instructions.

Here's current_row and desired_row in update_text_area one time.

TEXT: 13 glyphs
  0    0: IMAGE[10] str=0x13fb5c8[0] w=35 a+d=14+21 face=3 MB [ slice=0,0,24,24
  1   35: IMAGE[11] str=0x13fb5c8[1] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
  2   69: IMAGE[12] str=0x13fb5c8[2] w=29 a+d=14+21 face=3 MB slice=0,0,19,24
  3   98: IMAGE[13] str=0x13fb5c8[3] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
  4  132: IMAGE[14] str=0x13fb5c8[4] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
  5  166: IMAGE[15] str=0x13fb5c8[5] w=12 a+d=14+21 face=3 MB slice=0,0,2,24
  6  178: IMAGE[16] str=0x13fb5c8[6] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
  7  212: IMAGE[15] str=0x13fb5c8[7] w=12 a+d=14+21 face=3 MB slice=0,0,2,24
  8  224: IMAGE[17] str=0x13fb5c8[8] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
  9  258: IMAGE[18] str=0x13fb5c8[9] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
 10  292: IMAGE[19] str=0x13fb5c8[10] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
 11  326: IMAGE[15] str=0x13fb5c8[11] w=12 a+d=14+21 face=3 MB slice=0,0,2,24
 12  338: IMAGE[20] str=0x13fb5c8[12] w=34 a+d=14+21 face=3 MB ] slice=0,0,24,24
TEXT: 13 glyphs
  0    0: IMAGE[10] str=0x13fbe90[0] w=35 a+d=14+21 face=3 MB [ slice=0,0,24,24
  1   35: IMAGE[11] str=0x13fbe90[1] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
  2   69: IMAGE[12] str=0x13fbe90[2] w=29 a+d=14+21 face=3 MB slice=0,0,19,24
  3   98: IMAGE[13] str=0x13fbe90[3] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
  4  132: IMAGE[14] str=0x13fbe90[4] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
  5  166: IMAGE[15] str=0x13fbe90[5] w=12 a+d=14+21 face=3 MB slice=0,0,2,24
  6  178: IMAGE[16] str=0x13fbe90[6] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
  7  212: IMAGE[15] str=0x13fbe90[7] w=12 a+d=14+21 face=3 MB slice=0,0,2,24
  8  224: IMAGE[17] str=0x13fbe90[8] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
  9  258: IMAGE[18] str=0x13fbe90[9] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
 10  292: IMAGE[19] str=0x13fbe90[10] w=34 a+d=14+21 face=3 MB slice=0,0,24,24
 11  326: IMAGE[15] str=0x13fbe90[11] w=12 a+d=14+21 face=3 MB slice=0,0,2,24
 12  338: IMAGE[20] str=0x13fbe90[12] w=34 a+d=14+21 face=3 MB ] slice=0,0,24,24