bug#63187: 30.0.50; Tail of longer lines painted after end of nearby lines on macOS

[Alan Third]

On Mon, Jun 26, 2023 at 03:27:41PM +0800, Kai Ma wrote:
> 
> 
> > On Jun 25, 2023, at 20:46, Alan Third <alan@idiocy.org> wrote:
> > 
> >>> 
> >>> modified src/nsterm.m @@ -10622,7 +10622,7 @@ - (void) display
> >>> {
> >>>   NSTRACE_WHEN (NSTRACE_GROUP_FOCUS, "[EmacsLayer display]");
> >>> 
> >>> -  if (context)
> >>> +  if (context && context != [NSGraphicsContext currentContext])
> >>>     {
> >>>       [self releaseContext];
> >>> 
> >>> 
> >>> ...
> >>> 
> >>> Actually...
> >>> 
> >>> That change should probably be made anyway. If the NS run loop kicks
> >>> in between an ns_focus call and an ns_unfocus call, it could call
> >>> display and our display function will happily destroy the existing
> >>> context without creating a new one, so any *subsequent* drawing
> >>> operations, up until ns_unfocus, will be lost.
> >> 
> >> OK, I'm adding this to my current build.
> >> 
> >> Is this in line with the type of issue I'm seeing where scrolling
> >> works but the ghosting either replicates (or scrolls with it?) In
> >> other words, what would you expect to see in this scenario? Would it
> >> just stop painting entirely?
> > 
> > 
> > Kai, it might be worth trying just that change above, while keeping
> > the call to performSelectorInMainThread and see if it fixes anything
> > for you.
> 
> Unfortunately, the problem persists (as in the YouTube video) if 
> performSelectorInMainThread is present.

OK. Thanks for trying it.
-- 
Alan Third