Plasma::Svg: Do not require exact match for size hinted elements.
Review Request #5689 - Created Oct. 24, 2010 and submitted
Previously, if an SVG contained size hinted elements, they were only used when the display size matched the size hint exactly. This patch tries to relax this condition by searching for the smallest size hinted element that is still bigger than the display size (in order for the element to be chosen, it also has to have the same aspect ratio). If no such element can be found, it falls back to the normal element id as passed. In order to speed up the lookup (and because it appears to be impossible to access the DOM of an already loaded SvgRenderer), all size hinted element ids are stored in SharedSvgRenderer at load time. I think it would be good to change the QRegExp based id fetching into a proper DOM traversal. Are there any convenience functions in KDELibs that allow easy iterating over all elements (couldn't find any) or do I have to implement that myself based on Qt's DOM classes? Please tell me what you think... Have I missed something?
If you want to use the DOM to find the size hints, you can take a look at KGameSvgDocument. It implements a way to find elements by id. This could should be usable for you. And can you please measure how long it takes to load the SVG and to look for an element with and without your patch?
Ok, the performance should be acceptable and the patch looks good to me. I am fine with commiting but please wait for a go from a bigger plasma dev. ;)
Review request changed
As suggested by Manuel, this adds a macro for natural size hint cache keys, uses a non-greedy regexp to find size hinted elements and makes the theme return just a list of rect cache keys instead of a full map between keys and values. Additionally, the implicit QByteArray->QString conversion in QRegExp::indexIn(...) has been pulled out of the loop by explicitly converting the QByteArray beforehand.
Revision 7 (+169 -13)