On Feb 16, 2008, at 11:14, Paul Davis wrote:
Well, since I'm one of the most active developers of the gtk/osx port right now, I think you can assume I have my hands pretty deep in the mess :) And when I say "deep", I mean right inside the window redraw cycle at the intersection of Quartz/Cocoa and GDK. My codebase actual contains a bunch of patches that we hope will get into gtk/osx eventually, since they dramatically improve performance already :)
Awesome. I'm glad someone has their hands that deep in the pile =).
From what I can tell, the speed issues really are in Cocoa. And it struck me that when I survey the landscape of other apps that have the kind of GUI requirements that Ardour does, I don't know of a single one that was written with Cocoa. Most modern apps in my domain are tending to use openGL for x-platform purposes. The legacy apps are using Carbon because ... well, they're legacy apps ;) Shark gives me some pretty clear indications that the use of Cocoa inside the window update process is a killer.
I haven't really spent much time with Cocoa, myself. I've mentioned a few times on this list that I'm a C unix developer, and Cocoa/Quartz/ ObjectiveC are all new to me. Most of the hacking I've been doing has been on the "UNIX / C" side of X11 and not really ingrained in the Cocoa side of things. That being said, the major regression with 1.4 right now is deep inside our input control mechanism passing input events to Xinput from Cocoa, so I'll be walking further up this learning curve soon. I highly suggest that you file a radar ( http://bugreport.apple.com ) on this issue so someone in a position to fix performance in Cocoa knows about this issue and can work with you to fix it.
OK, thanks for the info. Just as a point of reference, the old "3rd party" X server for OS X (Ouroborous) had both these items (DnD, menubar).
Hmm... interesting. Thanks for the tip. I'll have to take a look at it (assuming it is MIT licensed).
It had a number of other nice features too - at least on paper; I never actually tried running it. I understand that the menubar thing is tricky - all the solutions I've actually seen at work are all X11-toolkit specific, and map a native menu onto the Carbon "main menu". Since X11 has no concept of a menu, its clear that its hard to integrate this at that level.
Yeah. I think there have been some "standard" ways of doing it that session managers have hooked into (mainly due to KDE's initiative to have "Apple style menu" support). We may be able to tap into that to actually bring X11 Apple Style Menus back to the XQuartz menu... but again... this is quite a ways off.
As a point of interest, given my quick grep through the xquartz code the other day: how *is* xquartz drawing the screen? Does it go via CoreGraphics/Quartz, or does it undercut that in some way? Does it blit an rgba buffer to the display, or actually use CG calls for more stuff? grep suggested to me that almost no CG calls are to be found inside the server source tree ....
Eh... hrm... this is a bunch of spaghetti to be honest. You certainly have a right to be confused. Right now (as of the very latest release), it is using pixman for the 2D rendering and GL calls are being passed directly to the native OpenGL framework. Part of the hope for 3.0 is to rebuild major sections of the DDX (possibly leveraging kdrive) using CoreGraphics/Quartz as much as possible. This was because of limitations that were in place during the initial design of X11 on OS-X (back in early Panther days). XQuartz is essentially that initial design fast-forwarded in time along X development. We've gotten it to somewhere around a year ago, and hopefully we'll be at "today" soon.