Re: Invisibility bug: `invisible' vs `display'

[Daniel Brockman <daniel@brockman.se>]

Daniel Brockman <daniel@brockman.se> writes:

> David Kastrup <dak@gnu.org> writes:
>
>> Daniel Brockman <daniel@brockman.se> writes:
>>
>>> Let me state again what I see:  The `display' property
>>> overrides `invisible' if and only if the previous character
>>> is visible.  How is this reasonable or useful in any way?
>>
>> When folding stretches of code, it does not make sense to
>> have images in between cluster all together and stick out
>> in spite of the invisibility of the region.
>
> I completely agree.

To clarify, this is exactly what I am trying to fix.

>> I am not saying that the current behavior is perfect, but it would
>> seem you would want to replace it with something that can cause quite
>> a bit of trouble, and I don't think we have the time to shake out all
>> repercussions before the release.
>
> On the contrary, I want to replace the current behavior with
> something that makes `invisible' _always_ override `display'.
>
> The current behavior is for `invisible' to override `display'
> in _almost_ every case.  In fact, all except one edge case.
> I simply want to eliminate this anomaly, which is causing me
> quite a bit of trouble.

This patch fixes the problem for me.

*** old/emacs/src/xdisp.c	2006-12-30 00:29:45.000000000 +0100
--- new/emacs/src/xdisp.c	2007-02-22 03:29:37.000000000 +0100
***************
*** 762,769 ****
    /* Handle `face' before `display' because some sub-properties of
       `display' need to know the face.  */
    {&Qface,		FACE_PROP_IDX,		handle_face_prop},
-   {&Qdisplay,		DISPLAY_PROP_IDX,	handle_display_prop},
    {&Qinvisible,		INVISIBLE_PROP_IDX,	handle_invisible_prop},
    {&Qcomposition,	COMPOSITION_PROP_IDX,	handle_composition_prop},
    {NULL,		0,			NULL}
  };
--- 762,769 ----
    /* Handle `face' before `display' because some sub-properties of
       `display' need to know the face.  */
    {&Qface,		FACE_PROP_IDX,		handle_face_prop},
    {&Qinvisible,		INVISIBLE_PROP_IDX,	handle_invisible_prop},
+   {&Qdisplay,		DISPLAY_PROP_IDX,	handle_display_prop},
    {&Qcomposition,	COMPOSITION_PROP_IDX,	handle_composition_prop},
    {NULL,		0,			NULL}
  };

I don't know enough about the display code to be able to say
whether this is a safe change, but it seems very logical to
me to handle the `invisible' property first, since invisible
text should just be skipped.

In fact, why not move it all the way to the top of that list?

-- 
Daniel Brockman <daniel@brockman.se>