When a string is broken at the margin by the Qt algorithm, the space
at which breaking occurred is automatically skipped in width
computation. However, the ending space of the string is taken into
account and is visible for example at paragraph end.
When the trailing space is followed by a displayed inset, then the
space should be skipped too, which means that the width of the last
row element has to be recomputed. For the sake of performance, the
width of the element without trailing spaces is computed in advance in
FontMetrics::breakString.
This "no space" width will be used when trimming a row element of its trailing
spaces instead of the original one.
Additionally, do not trim trailing spaces when the row is flushed.
Fixes bug #12449.
The search widget triggers a showEvent() in updateTitle() leading to setting the focus to the default push button.
The check in updateTitle() for the need to restore the title avoids superfluous show events and avoids the unwanted focus change.
The checkbox is hidden when backing store is enforced (wayland,
macOS). In practice, only X11 and Windows users will see it ; I only
have evidence of X11 people needing it, I can hide it for Windows
users too if necessary.
Fixes bug #12119.
LyX relies on a a backing store to draw when running under macOS or
Wayland, because Qt arbitrarily overwrites parts of the workarea
before we paint (and we paint only the parts that need to be painted).
However it seems that this is also necessary on X11 when the WM theme
is translucid. Since there is no way that I know of to detect this
situation, this patch adds a LyXRC setting to manually select this
drawing strategy.
Note that using a backing store is not always a good solution, since
this disables subpixel aliasing.
At this point there is no UI for the variable.
Fixes bug #12119
The default in the .ui is not considered in
GuiSearchWidget::restoreSession(), which sets a hard-coded default
if the stored setting is not found in the session file.
I'll start an ML discussion for whether the code in restoreSession()
should use the ui's default if the setting is not found in the
session.
Increase the maximal size of the breakString cache (to compute where
to break lines) from 512kB to 10MB. This has a big impact of cache
hits on large file like the example in #12297, which is now 99%. On
this example the time taken by breakString decreases from 33.5us to
2.4us.
The string width cache has been increased fro 512kB to 1MB, but this
does not make such a big difference.
Additionally, comments and variable names have been improved.
Related to bug #12297.
Replace FontMetrics::breakAt, which returned the next break point,
with FontMetrics::breakString, which returns a vector of break points.
To this end, an additional parameter gives the available width for
next rows.
Rename various variables and methods accordingly. Factor the code in
breakString_helper to be more manageable.
Adapt Row::Element::splitAt to return a bool on sucess and provide
remaining row elements in a vector. The width noted above has been
added as parameters.
Rename the helper function splitFrom to moveElements and rewrite the
code to be more efficient.
Remove type of row element INVALID, which is not needed anymore.
The code in TextMetrics::breakParagraph is now much simpler.
In Row::finalize, remove the code that computed inconditionnally the
current element size, and make sure that this width will be computed
in all code paths of Row::Element::splitAt.
In this case, the extra element returned should empty but valid. The
row flag BreakAfter is set to indicate that we have a break there
(this principle will be used more generally in a forthcoming commit).
To detect that we cut at the trailing space, it is necessary to rely
on the difference between QTextLine::horizontalAdvance() and
QTextLine::naturalTextWidth() when the flag
QTextOption::IncludeTrailingSpaces is used: the trailing space is
taken into account in the later, but not in the former.
Somme comments have been added to make code intent clearer.
At least with Qt 4.8.7 on Ubuntu 16.04, QTextLine::lineWidth() can
return a bogus value, at least with Courier font. One hypothesis is
that the invisible characters that we use in breakAt_helper are given
a non-null width.
Work around it, although the exact bug has not been pinpointed.
Since we intend to break the row element in two, it is not good to
truncate the string too early.
Moreover, the row element width is now set at this point, even if no
breaking occurs.
