Do not cut strings at separators in RowPainter when text is not
justified. This speeds-up painting by reducing the number of strings
to draw.
Do also a modest cleanup of paintChar (remove dubious optimization).
Instead of relying on character range (Hebrew or Arabic) or character
direction, use RLO unicode character (Right-to-Left override) to force
painting in the direction indicated by the current font. This should
be as close as we can to the old LyX behavior (and requires less
code).
If this code works as intended, it will be possible to remove a lot of
code from Encodings.cpp.
We rely on Qt built-in unicode support for handling Arabic and Hebrew
compose characters. This allows to avoid to use our homegrown
machinery.
This should provide a nice speedup at a low cost and
will eventually allow us to get rid of:
* most of our Arabic/Hebrew machinery in Encodings.cpp,
* Paragraph::transformChar,
* and probably more.
All these problems are related to what happens at the extreme points of rows
* since VIRTUAL elements have a width but no contents, they have to
be treated specially at some places. It would have been better to
avoid testing for them explicitly, but I did not find a way.
* Improve and cleanup the code in breakRow and fix in passing a crash
when clicking on the right of an incomplete MARGIN_MANUAL
paragraph.
* improve the computation of row width in TextMetrics::computeRowMetrics.
* handle properly the case where a position if not found on the row
in both cursorX and getPosNearX (actually, this happens when
selecting).
* Some code cleanup and comments.
* fix handling of boundary situations in Row::Elements::x2pos;
* fix handling of boundary situations in TextMetrics::getColumnNearX;
* make sure to always use Font::isVisibleRightToLeft instead of Font::isRightToLeft;
* Improve debug messages.
The horizontal position of the inset was not taken in account.
The rounding is not always the same as with the old code, but this
is not really important.
Additional changes:
* improve debug output of rows
* remove Bidi& argument of the RowPainter constructor, since it is always
an empty Bifi that is passed. This means that the Bidi class is not
used at all any more in TextMetrics.cpp. The only remaining user is
RowPainter.
Break words longer than the screen width. The code is more complicated
than I would like, but I have no better idea right now.
Implement properly the notion of a row broken by a display inset. This is useful in different places.
Also fix a bug with last line of a paragraph spotted by Kornel.
Use proper font everywhere for end-of-par marker
Fix getColumnNearX for RTL text and for centered/right-justified paragraphs.
Let computeRowMetrics update the row width.
* convert cursorX to new scheme; old computation is still there for the sake of comparison.
* use Row to compute separator width in computeRowMetrics; again, the old code is retained for now.
* Get rid of rowWidth()
* Row now contains a vector of Elements
* replace Row::dump by a proper << operator
* the width is updated as elements are added
* breakRow is reimplmented to use this infrastructure
