-This branch is where I (jmarc) try to implement string_wise metrics
-computation. This is done through a series of cleanups. The goal is to
-have both good metrics computation (and font with proper kerning and
-ligatures) and better performance than what we have with
-force_paint_single_char.
+
+!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+PLEASE DO NOT DO WORK ON TOP OF THIS BRANCH.
+I INTEND TO REWRITE HISTORY LATER!!!
+!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+This branch is where I (jmarc) try to implement string-wise metrics
+computation. The goal is to have both good metrics computation (and
+font with proper kerning and ligatures) and better performance than
+what we have with force_paint_single_char. Moreover there has been
+some code factorization in TextMetrics, where the same row-breaking
+algorithm was basically implemented 3 times.
Currently everything is supposed to work for LTR text, and RTL text
should work too except possibly metrics with Arabic and Hebrew fonts.
-We'll see what to do after some feedback.
+
+When KEEP_OLD_METRICS_CODE is defined in TextMetrics.cpp, the new code
+is tested against the old one in getPosNearX and cursorX. This can be
+helpful when looking for discrepancies between the algorithms. Note
+that this only makes sense when force_paint_single_char=true, since
+this enforces char-by-char metrics computation.
What is done:
* Make TextMetrics methods operate on Row objects: breakRow and
setRowHeight instead of rowBreakPoint and rowHeight.
-* Change breakRow operation to operate on text strings on which
- metrics are computed. The list of elements is stored in the row
- object in visual ordering, not logical.
+* Change breakRow operation to operate at strings level to compute
+ metrics The list of elements is stored in the row object in visual
+ ordering, not logical. This will eventually allow to get rid of the
+ Bidi class.
* rename getColumnNearX to getPosNearX (and change code accordingly).
It does not make sense to return a position relative to the start of
Next steps:
-* check what happens with arabic and/or hebrew text. There may be some
+* check what happens with Arabic and/or Hebrew text. There may be some
problems related to compose characters. I suspect that some code is
needed in FontMetrics::width.
+* investigate whether RtL strings could be drawn on a string-wise basis.
+
+* investigate whether Row::SEPARATOR elements could be used only in
+ justified text. This would speed-up painting in other cases by
+ lowering the number of strings to draw.
+
+* get lots of testing.
+
* Get rid of old code in cursorX and getColumnNearX; it has been
kept for comparison purpose, guarded with KEEP_OLD_METRICS_CODE in
order to check computations.
+* Profile and see how performance can be improved.
+
+
+Steps for later (aka out of the scope of this branch):
+
* Re-implement row painting using row elements. This is not difficult
in principle, but the code is intricate and needs some careful
- analysis. First thing that needs to be done is to break row elements
- with the same criterions. Currently TextMetrics::breakRow does not
- consider on-the-fly spellchecking and selection changes, but it is
- not clear to me that it is required.
+ analysis. The first thing that needs to be done is to break row
+ elements with the same criteria. Currently TextMetrics::breakRow
+ does not consider on-the-fly spell-checking and selection changes,
+ but it is not clear to me that it is required. Moreover, this thing
+ would only work if we are sure that the Row object is up-to-date
+ when drawing happens. This depends on the update machinery.
-* Profile and see how performance can be improved.
+ This would allow to get rid of the Bidi code.
-Difference in behavior (aka bug fixes)
+Known bugs:
+
+* in RtL paragraphs, the end-of-paragraph marker moves the row to the
+ right (ticket #9040, already present in master).
+
+* there are still difference in what breaks words. In particular,
+ RowPainter breaks strings at: selection end, spell-checking
+ extremities. This seems to be harmless.
+
+* when clicking in the right margin, GetColumnNearX does not return
+ the same value as before. I am not sure whether this is important.
+
+
+Other differences in behavior (aka bug fixes):
* end of paragraph markers metrics are computed with the font of the
actual text, not default font.
-* When cursor is after a LTR separator just before a RTL chunk, the
+* When cursor is after a LtR separator just before a RtL chunk, the
cursor position is computed better with the new code.
-Other differences (aka real bugs)
-
-* there are still difference in what breaks words. In particular,
- RowPainter breaks strings at: selection end, spellchecking
- extremities.
-
-* when clicking in the right margin, GetColumnNearX does not return
- the same value as before.
* Full author contact details are available in file CREDITS.
*/
-#define KEEP_OLD_METRICS_CODE 1
+//#define KEEP_OLD_METRICS_CODE 1
#include <config.h>
bool boundary) const
{
LASSERT(sl.text() == text_, return 0);
- pit_type const pit = sl.pit();
- pos_type pos = sl.pos();
- ParagraphMetrics const & pm = par_metrics_[pit];
+ ParagraphMetrics const & pm = par_metrics_[sl.pit()];
if (pm.rows().empty())
return 0;
Row const & row = pm.getRow(sl.pos(), boundary);
-
- double x = row.x;
+ pos_type const pos = sl.pos();
/**
* When boundary is true, position i is in the row element (pos, endpos)
if (row.empty()
|| (row.begin()->font.isVisibleRightToLeft()
&& pos == row.begin()->endpos))
- return int(x);
+ return int(row.x);
Row::const_iterator cit = row.begin();
+ double x = row.x;
for ( ; cit != row.end() ; ++cit) {
if (pos + boundary_corr >= cit->pos
&& pos + boundary_corr < cit->endpos) {
<< ", " << boundary_corr << "): NOT FOUND! " << row);
#ifdef KEEP_OLD_METRICS_CODE
+ pit_type const pit = sl.pit();
Paragraph const & par = text_->paragraphs()[pit];
// Correct position in front of big insets
projects / features.git / commitdiff