Qt on macOS does not respect the Qt::WA_OpaquePaintEvent attribute and
clears the widget backing store at each update. Therefore, we use our
own backing store in this case.
This restores a simplified version of the code that was removed at 24c29908.
Now the helper class contains logic that checks whether buffer are
known before closing them. This avoids potential crashes.
Use it in different places to siplify code. It is not clear at this
point whether it should be used everywhere.
Followup to bug #10847.
When a buffer is in an embedded work area (adv. find&replace), it is
not found by BufferList:::exists(), and therefore the undo group
created in GuiApplication::dispatch and in the handling of
LFUN_COMMAND_SEQUENCE will not be closed.. Crashes can ensue, as
described in Ubuntu bug:
https://bugs.launchpad.net/bugs/1737429
The solution is to introduce BufferList::isInternal and act on it.
Fixes bug #10847.
This is a follow-up to 758de957.
- unify the metrics and drawing of \sqrt and \root using helper
functions mathed_root_metrics and mathed_draw_root.
- compute the vertical spacing above the nucleus of the root following
rule 11 of the TeXbook. In particular, it is different in inline and
display style.
- draw the root glyph without hard-coded pixel values. Make the line
width depend on the zoom.
more work is needed to implement properly rule 11:
- Ideally, we should use sqrt glyphs from the math fonts. Note that
then we would get rule thickness from there.
- The positioning of the root MathData is arbitrary. It should
follow the definition of \root...\of... in The Texbook in
Apprendix B page 360.
Fixes bug #10814.
It may happen that the buffers are visited in order buffer1,
buffer2, buffer1. In this case, we want to have only one undo group
in buffer1. The solution is to replace buffer_ with a set<Buffer*>.
A use case among others is InsetLabel::updateReferences.
The bug is the following: when selecting several paragraphs quickly
enough, some rows do not get selected.This is a consequence of the
removal of row crc, which lead to not taking into account the
selection status of the row in the decision to repaint.
The solution chosen here is to add a Row::change() helper function to
modify row members. This will set the Row changed status whenever the
value of the member changes.
