It is a bad idea to have a QObject variable that oulives the main QApplication object. See for example:
https://www.ics.com/designpatterns/book/globals.html
Here the QTextLayout object was static to the anonymous namespace getTextLayout function, and got destroyed after the freetype renderer had been disposed of by QApplication.
This causes segmentation faults when quitting LyX on some systems.
This patch moves the cache together with other GuiFontMetrics caches. It means that one will have one such QTextLayout per font type, but this will not change much.
This is better because it implements a LRU cache. Indeed, while editing in particular, width of many different strings has to be computed. This is different from the previous situation where only width of single characters was computed and cached.
* GuiFontMetrics::pos2x, x2pos: add support for inter-word spacing.
* GuiPainter::text: idem
* Row::Element::countSeparators:
Row::countSeparators: new methods that count spaces in strings.
Row::setSeparatorExtraWidth: new method (code lifted from TextMetrics.cpp).
* TextMetrics::computeRowMetrics: rely on the above methods.
* RowPainter::paintMispelledMarked: pass only a Row::Element object reference
RowPainter::paintStringAndSel: idem; do not rely on values returned by
Painter::text (trailing spaces do not honor wordspacing value).
The goal of this commit is to make painting faster by reducing the
number of strings to paint. To this end, it is necessary to include
spaces in row elements.
Also importantly, this commit should fix existing problems with line
breaking in chinese text.
* TextMetrics::breakRow: do not do anything special for word separators.
* Row::add: when adding a character to a row element, keep the string
width updated. If need be, it is possible to tweak this by updating
every 10 characters, for example.
* GuiFontMetrics::breakAt (new): use QTextLayout to break text either
at word boundary or at an arbitrary width.
* Row::Element::breakAt: use the above method.
* Row::shortenIfNeeded: simplify now that because there is no need for
handling separator elements. This will be taken care of by the
improved breakAt.
Two things remain to be done:
* remove all traces of separator row element
* re-implement text justification.
The computation of length on screen depend in particular of the computation of the size of an em. Many places of the code used to rely on the width of the M character, which is not really correct:
http://en.wikipedia.org/wiki/Em_%28typography%29
In digital typography, the best value to use is the point size of the font.
* Implement FontMetrics::em(), which returns the value in pixels of the EM unit.
Convert code to use it.
* Introduce Length::inPixel(MetricsBase const &), which takes the textwidth and em information from the MetricsBase object. Convert code to use it.
* Fix several places where Length::inPixel is used without a proper em value.
* add mathed_font_em() helper function. It should eventually be removed like some other functions in MathSupport.
* Add dummy implementation of FontMetrics to tex2lyx for linking purposes.
The old implementation of Row::Element::pos2x and x2pos did not work
correctly with Arabic text, because characters can have shapes that
depend on context.
This new implementation leverages QTextLayout in a simplified way,
since only one word is added to the layout.
This allows to make Row::Element::x2pos more readable.
Fixes: #9115.
This has the advantage of simplifying our code and to produce the
correct output: the small capitals should have the exact same width as
the lower case letters.
The slanted fonts are also translated to oblique on Qt side, but this
does not seems to have an effect in my testing. It may be that proper
oblique fonts need to be installed.
Gcc 4.7 warns that this kind of narrowing is illegal in C++11, so
we can just as well fix that right now.
In GuiFontMetrics this is fixed by chaning the types in the AscendDescend struct
from short int to int.
In ParagraphMetrics it is fixed by addint explicit casts.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@40586 a592a061-630c-0410-9148-cb99ea01b6c8
http://bugzilla.lyx.org/show_bug.cgi?id=3759
It also simplifies and fix the smallcaps case which was not correct WRT unicode. Even though I don't know if toUpper() means something in the non ucs2 range.
FYI, I used toqstr() to do the ucs4 -> ucs2 conversion when needed. This helper method works only with Qt >= 4.2.
* GuiFontMetrics::smallcapsWidth(): changed to work with single ucs4 characters.
* GuiFontMetrics::xxx(): make sure that font metrics works with characters not in the ucs2 range.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@18593 a592a061-630c-0410-9148-cb99ea01b6c8
* FontMetrics.h: only one string width() method.
* Painter.h: only one text() method.
* all other files: adapt to above API change.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@17362 a592a061-630c-0410-9148-cb99ea01b6c8
* introduce defaultDimension() and dimension() in preparation of Dimension class cleanup.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@16165 a592a061-630c-0410-9148-cb99ea01b6c8
- ucs4_to_qchar(): add a FIXME and an assertion
* GuiFontMetrics: replace the table based cache with two QHash based cache. With this change, the speed overhead is not negligible (exact same score with the UserGuide test) and the required additional memory is minimal (maybe one or two megabytes).
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@16132 a592a061-630c-0410-9148-cb99ea01b6c8
- add constants instead of hard-coded values.
- add assertions and comments for out of range values.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@16126 a592a061-630c-0410-9148-cb99ea01b6c8
http://bugzilla.lyx.org/show_bug.cgi?id=2900
The only drawback is that it requires about 20Mo extra-memory when loading the UserGuide. If it turns out to be too much, we can switch to a QHash based solution instead of a table.
* dimension.[Ch]:
- Dimension(LyXFont const, char_typec): new ctor
- set(LyXFont const & font, char_type c): new method.
* frontends/FontMetrics.h:
- width(char_type): is now a pure virtual method.
* GuiFontMetrics:
- CharMetrics: new structure;
- the metrics cache now also cache ascent and descent. This is especially useful for mathed.
* MathSupport.[Ch]:
- mathed_char_dim(): deleted. We now use Dimension::set() directly instead.
* rowpainter.C: fixe empty space.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@16124 a592a061-630c-0410-9148-cb99ea01b6c8
* QLPainter::paintText(): use GuiFontMetrics::metrics(QString) to avoid an ucs4 to QString conversion.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@15584 a592a061-630c-0410-9148-cb99ea01b6c8
Basically, I replaced all methods in the font_metrics namespace by a proper virtual interface FontMetrics. The FontLoader is _the_ container for FontMetrics.
This patch should also bring some optimizations in a number of place in the code. This is because we do not need any more to search for the LyXFont at each font_metrics call. In effect, the speed advantage is not as sensible and this is a bit deceiving considering that this was my primary motivation behind the patch. But I like the patch anyway as it cleans up the relation and interfacing between fonts, metrics and frontends.
* frontends/FontMetrics.h: new virtual interface. Renamed from font_metrics.h
* qt4/GuiFontMetrics: corresponding qt4 implememtation. Renamed from qfont_metrics.C. The smallCaps particular case treatment has been transfered here as well as the width cache for MacOSX and Windows.
* qt4/QLPainter.C: the smallCapsText has been reworked to return the width of the drawn text.C
all other files: replace font_metric helper function call with corresponding FontMetrics method calls.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@15265 a592a061-630c-0410-9148-cb99ea01b6c8
