Am 13.01.2011 um 09:28 schrieb Abdelrazak Younes: > On 01/13/2011 09:23 AM, Stephan Witt wrote: >> Am 13.01.2011 um 09:07 schrieb Abdelrazak Younes: >> >>> On 01/13/2011 08:48 AM, Pavel Sanda wrote: >>>> Stephan Witt wrote: >>>>> The metrics cache computes the width of every single character - >>>>> inclusive cacheing of it (to get better performance). But the >>>>> drawing is done with complete text strings and if a font supports >>>>> kerning e.g. it's absolutely correct to respect it on drawing. >>>>> >>>>> LyX cursor positioning simply operates in a parallel universe... >>>>> ... and uses the metrics cache numbers. >>>>> >>>>> See ticket http://www.lyx.org/trac/ticket/6920 >>>> its clearly not just mac os thing. this starts to be currently >>>> most annoying bug we have and the proper solution probably means >>>> rewrite the painting routines. >>>> >>>> http://www.lyx.org/trac/ticket/7235 >>> There are three solutions: >>> >>> 1) compute the metrics 8 times for a word of 8 letters >>> 2) draw letter by letter all the times. >>> 3) or rely on more on Qt widgets (i.e. use QTextEdit) instead on doing our >>> thing. >>> >>> 1) would be costly in terms of performance >>> 2) would add be need a bit more cpu and would have the side effect that >>> kerning would not be as good Qt's word drawing. This is what we do already >>> for arabic and hebrew. >>> 3) is a very big task and an entirely unknown territory. Our pixmap backend >>> is very fast and has been optimized through the years... I am not sure we >>> can get achieve the same performance with QTextEdit for a 1000 pages of >>> rich text. >>> >>> So, all in all, I vote for (2) as an lyxrc option. That is the easiest to >>> implement and offers the best tradeoff between performance and beauty. >> Since it depends on the used fonts and the used qt-version I cannot see why >> to use a lyxrc option. > > The rc option is the easiest to implement and can be turned on/off for > testing for this or that font. We don't need a Gui for that option. In the > future when the user changes font we can automatically adjust the option.
Ok. > I don't think hardcoding for some Qt version and some fonts is a good idea. It's a new problem with qt4.7 (on mac at least). > >> To be on the save side - if nothing else is changed - you have to draw >> letter by letter all the times anyway. > > The option can set to true by default. IMHO, it should be true by default for qt4.7. Stephan
