Dov Feldstern schrieb:
Bernhard Roider wrote:
Hello Stefan,
today i finally found some time to investigate the problem we
discussed at the beginning of march concerning the completion list:
rtl text does not work and icons are not displayed for math symbols.
Here is a patch that solves that issue for me using qt 4.2.3. There
are two things that caused the problem:
1. QCompleter::setModel() changed the item delegates internally, so
the specialized ones vanished
2. item delegates for columns are not used --> qt bug?
The attached patch solves both issues so that it works with my qt
version. It should be tested for newer versions of qt.
...
bernhard
Hi!
What exactly is the problem with RTL completion that this patch is
trying to solve? Can you separate out the part dealing with RTL from the
rest of the patch?
Without your patch, I'm seeing (Linux, Qt 4.2.1) RTL completion behave
correctly, except for the fact that the inline completion (the grayed
out part) is reversed; the list of completions, though, behaves correctly.
With your patch applied, also the strings in the completions list are
reversed.
Applying the attached (very complicated ;) ) patch *instead* of yours
fixes the problem of the inlined strings, without adversely affecting
the completions list.
I believe that what's happening is this: the completions list is
presumably getting the strings in "logical" order (the way they're held
in memory). When the strings are painted (both in the list and inlined),
since they are being painted as an entire string at once (and not one
character at a time, as we normally do with RTL text) Qt is applying its
own bidi algorithm, and thus the strings are painted correctly,
*provided* that the strings are really composed of true RTL characters
(Qt does not know about our marking text as RTL, it only knows if text
is RTL or not based on the unicode values). You guys were probably
testing the RTL capabilities with Latin characters, so Qt was *not*
reversing the strings, and thus the strings appeared to you to be
painted backwards, which is why you were applying an extra reversal.
Your guess is correct. With my patch the completion list works for qt 4.2 as it does for higher
versions, that is
1. display the icons for math symbols
2. reverse the strings in the list if they are rtl.
I'm not sure whether locale settings affect this or not, but I think
that they don't, as long as there is a *legal* locale setting.
In summary, I think that the reversals should be removed, as in the
attached patch. If most of Bernhard's patch is still relevant for
non-RTL issues, then the RTL-specific issues should be removed from it,
as well.
Stefan, will you take a look at this?
Bernhard
To be sure, this solution isn't perfect, because we're being
inconsistent by letting Qt do some of the bidi work, and doing some of
it ourselves; and this becomes visible precisely in the pathological
cases where there's a difference between us and Qt, such as Latin text
which we mark as RTL; but for normal RTL usage, I believe the reversals
should *not* be done.
Dov
