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List:       kde-commits
Subject:    branches/KDE/4.1/kdelibs/kdeui/plotting
From:       Jason Harris <kstars () 30doradus ! org>
Date:       2008-08-25 15:04:01
Message-ID: 1219676641.360550.4600.nullmailer () svn ! kde ! org
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SVN commit 852217 by harris:

backporting fix from trunk (r851444): 

Improved "smart" placement of text labels for plotted points that have 
been named.  The previous method used a low-resolution "gridding" of the plot 
region into a 100x100 array (regardless of the plot widget's size) to serve as 
a mask to identify regions which already contain a plot element.  Now we use an 
actual image for the mask, matched to the size of the widget.  

In addition, we use a "downhill simplex" algorithm to search for an 
optimal  label position near the target point such that the label doesn't overlap with 
other plot elements.  Before we used a brute-force search.  

With the new method, the Solar System tool in KStars takes 85-95 msec to 
draw itself (compared to 250 ms with the old code, and 75-85 msec with no 
point labels).



 M  +234 -123  kplotwidget.cpp  


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