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This is an automatically generated e-mail. To reply, visit:
http://git.reviewboard.kde.org/r/101867/
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(Updated July 6, 2011, 3:04 p.m.)


Review request for Calligra and Casper Boemann.


Changes
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added suggestion for an alternate solution


Summary (updated)
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Attached patch fixes QTextLine-positioning on right-to-left.

During layouting it can happen that line.naturalTextWidth() > line.width. This 
can be reproduced with the small testapp I wrote and uploaded to 
http://www.2shared.com/file/AwZJc-uG/testapp.html . There just go to e.g. the 
3th line, press the PosEnd-Key (to go to the beginning of the line) and add 
tons of spaces. Spaces seems to be handled different here cause even with 
left-to-right they never result in a line-break but are always added to the end 
(or in the case of right-to-left to the beginning) of the line what can the 
result in line.naturalTextWidth() > line.width. For reference also have a look 
at Qt's qtextdocumentlayout.cpp:2616 to the "if 
(QFixed::fromReal(line.naturalTextWidth()) > right-left)" block.

Now on left-to-right the previous solution (aka before the patch) was and still 
is fine. In that case the produced QTextLine just cuts such additional spaces 
off on the right side. No visible harm is done. But on right-to-left the 
problem is that such spaces are added at the beginning of the line and 
therefore we cut off visible text at the right side.

The patch fixes the right-to-left case by adjusting the line's position 
according so we make sure that the spaces at the beginning are cut off rather 
then text at the end. This is very similar to what Qt does with 
QTextEdit+QTextDocument (see the aboved linked test app).

NOTE:
An alternate solution would be to just cut off the spaces at the left without 
changing the line's position but seems that's way more complicated since the 
spaces added to the beginning somehow are always preserved. Probably cause they 
are detected as left-to-right rather the right-to-left. To proper handle that 
we would need to walk backwards once right-to-left text is detected and then 
change QTextFormat to have the proper layoutDirection.
Maybe that would be an even better solution? But then we would maybe need to do 
the same on editing...


Diffs
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  libs/textlayout/KoTextLayoutArea.cpp 1308574 
  libs/textlayout/KoTextLayoutArea_paint.cpp cdb42bf 
  libs/textlayout/RunAroundHelper.h e358ff6 
  libs/textlayout/RunAroundHelper.cpp 942aaa4 

Diff: http://git.reviewboard.kde.org/r/101867/diff


Testing
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This solves a problem with an arabic right-to-left document I got. Since that 
document is confidential I am not allowed to create a BKO bug-report for it :-( 
But at least the author allowed me to use it to investigate the issue to 
produce this fix :-)


Thanks,

Sebastian

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