The composite methods are not more efficient. It isn't possible to 'ignore' the current transform matrix - it's possible to do further calculation to undo (parts of) its effects. This is what the composite methods do. The primary reason to avoid the composite methods is that they have surprising semantics. Normally, all drawing is with respect to the coordinate system set up in -[NSGraphicsContext currentContext]. Unlike everything else, before drawing, the composite methods manipulate the current transformation matrix to be the identity matrix (or more accurately, the identity scaled up by the default user space scale factor – think default window scaling with resolution independence). That basically means that in a scaled or rotated view, composite methods draw as if the view is not scaled or rotated, though it can means something different if drawing to something other than the window itself. This isn't usually what one is really after. In fact, if anyone is using the composite methods intentionally to get this effect, I'd like to hear about it!
Often people use these methods because they seem to produce right-side-up drawing in flipped views (though you still branch your layout on the flippedness, since the point you pass to compositeToPoint: becomes the visual bottom of the image). I gave a less surprising method of doing that in <http://lists.apple.com/archives/cocoa-dev/2008/Oct/msg01266.html>. This reply is a little bit complicated. That's because the methods are, which is the point. :-) -Ken Cocoa Frameworks On Fri, Oct 17, 2008 at 9:04 PM, Matt <[EMAIL PROTECTED]> wrote: > Recently found this in the Apple NSImage docs re: CompositeToPoint method: > > "Important: If you are writing new code, or updating old code, you > should avoid using this method. Instead, you should use the > drawAtPoint:fromRect:operation:fraction: or > drawInRect:fromRect:operation:fraction: method to draw the image. > Although the method itself is not deprecated, the behavior it provides > is not recommended for general use." > > I am currently using compositeToPoint extensively in one of my > projects because I read in the apple drawing guide that it is more > efficient since it ignores some extra checks like bounds and view > rotation, etc. > > I have had trouble finding any other details on the above warning in > the docs. Does anyone have any information they might be able to share > on why 'compositeToPoint' is 'not recommended for general use'? > > Thanks in advance, > -Matt > _______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > 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/kenferry%40gmail.com > > This email sent to [EMAIL PROTECTED] > _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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]
