Hi Keith,
I have certain custom text attributes that are used in my NSTextStorage to which I would like to add temporary attributes via the NSLayoutManager.
What version of OSX are you testing under? Under Leopard there's a bug in -[NSLayoutManager temporaryAttribute:atCharacterIndex:longestEffectiveRange:inRange:] that calculates effective ranges that are too short. For specific test cases this caused big inefficiencies in the text system. I believe this bug is fixed in Snow Leopard.
more recently I have taken to overriding NSLayoutManager's - temporaryAttributesAtCharacterIndex:effectiveRange:
If this is too slow, then I'd look to using some kind of cache for your calculations. But really, NSLayoutManager's temporary attributes are already a cache; one likely to be specifically designed for high performance index/run access. I think your original idea of setting temporary attributes whenever text changes would be the most efficient.
Perhaps you're recalculating too much, too often? I don't know the access patterns for temporary attributes, but I would guess they are only queried when associated text is displayed on screen. If that's the case, you could fix them up lazily, eg: whenever text changes just note down that the attributes are dirty in that range. Your temporary attribute methods in your NSLayoutManager subclass can then ensure that temporary attributes are not dirty before they are returned.
If none of that is efficient enough, you could rig up a NSTextStorage subclass that has two sets of attributes: one set for private use and another derived set which only the layout system sees.
Hopefully some of that helps, ~Martin _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
