[PUSHED] Recompute column widths in BackingWindow::Resize() to partially fix #34392

[Andras Timar]

Gábor Stefanik <netrolller.3d at gmail.com> írta (2012. április 9. 18:31):
> 2012/4/9 Andras Timar <timar74 at gmail.com>:
>> Gábor Stefanik <netrolller.3d at gmail.com> írta (2012. április 7. 2:13):
>>> With this patch, the start screen displays correctly on startup with
>>> scaling set to 130% (tested on OpenSUSE 11.4 x86-64).
>>>
>>> However, if you start LibreOffice with scaling @ 100%, then change
>>> scaling to 130% with the start screen still open, the bug remains.
>>> I've looked into it, and this appears to be a separate issue -
>>> Resize() is called too early on scaling change, before the new scaling
>>> factor is available. As a result, GetTextWidth() uses the old scaling
>>> factor to compute widths.
>>>
>>> If anyone can point me towards where Resize() is called on the scaling
>>> change codepath, that would be greatly appreciated.
>>>
>>
>> Even without your patch, resizing works in the following scenario:
>> 1. Set scaling to 130% (and observe the clipped text)
>> 2. Press e.g. Text Document button to start Writer.
>> 3. Close Writer with the X control at the top right of the window.
>> 4. Observe that the start center buttons are resized correctly.
>>
>> So basically you are right, the scaling information is missing in the
>> first call, and it is present in subsequent calls.
>> http://opengrok.libreoffice.org/xref/core/framework/source/services/backingwindow.cxx#627
>> calculates the text width. It is always 100% when called first,
>> regardless of the scaling factor. You need to find out why, e.g. by
>> setting a breakpoint to BackingWindow::initControls() and see the
>> backtrace at each call.
>>
>> Andras
>
> Yes, the case that this patch fixes is the following:
> 1. Set scaling to 130% (and observe the clipped text)
> 2. Press e.g. Text Document button to start Writer.
> 3. Close Writer with the X control at the top right of the window.
> 4. Observe that the start center buttons are resized correctly.
> 5. Close and re-open LibreOffice.
>
> After step 5, without the patch, the buttons are misrendered. With the
> patch, they are resized correctly.
>
> Another interesting effect I noticed:
> 1. Start up with scaling set to 100%. (Correct rendering.)
> 2. Set scaling to 130%. (Clipped text - the buttons do not grow.)
> 3. Set scaling back to 100%. (Now the buttons are too large - they are
> sized as if the scaling was still 130%.)
>
> I've done some debugging (Is there any way to set "make debugrun" to
> use something other than plain gdb? I usually use kdbg.), and found
> that GenericSalLayout::GetTextWidth() is using incorrect glyph width
> values. Apparently the font size is being set only after
> BackingWindow::Resize().
>
> (Debugging is further complicated by the fact that as I try to
> rearrange the code calling Resize() to test various possible fixes, I
> often get mysterious segfaults which gdb often maps to blank lines in
> the source code between function definitions. Go figure.)
>

Pushed (combined with your second patch, which gave a full solution to
the issue).
Thanks,
Andras