From: Milton Aupperle <milton@outcastsoft.com>

Date: September 3, 2009 9:31:18 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: Multiple display support

Hi Malte;

On 3-Sep-09, at 6:21 AM, maltetewes wrote:

What I did is to turn off display-mirroring, put AstroIIDC's preview window on the beamer while keeping the control window on the laptop screen, hiding the dock, and setting the beamer to a very low resolution (... 640 x 480, thus keeping the AstroIIDC zoom at 100%). Well I still had that menubar on the beamer, but otherwise it was perfect. (actually I even used multiple desktops to switch between a moon chart and live view etc... plus you can get a black menubar by using the negative-image setting in the system prefs.

Extemely important here is the framerate : I experienced that I couldn't get a fast live view using AstroIIDC's own zoom and keeping the beamer's resolution at native value. And for such presentations, all the pleasure really comes from the faster-then-turbulence framerate...

Just so you know, the Zoom is done using Apple's "Core Graphics". It's anywhere from 30% to 100% slower than using the 25 year old "QuickDraw" copybits calls for blitting images, and the performance hit varies depending on size. I've bench marked this for both Intel and PowerPC for Panther Tiger and Leopard. Going to OpenGL (or possibly OpenCL in Snow Leopard) would improve things, but that has issue or works erratically with multiple displays depending on what Graphics Card you have (model, Ram, GPU and manufacturer all make a huge difference).

Secondly, if your using a version earlier than 4.0x of Astro IIDC with Leopard or earlier and also have Astro IIDC drawing text on the screen (i.e. sharpness numbers etc.), that triggers another major CPU hog in Core Graphics. Drawing a single letter on screen (like the letter  "A")  on screen at 30 fps was using up 40% of the CPU under Tiger or Panther. That has dropped to 8% in Leopard, however I stopped using Core Graphics for text drawing and went back to 10+ year old ATSUI text drawing method which uses about 3% cpu usage to draw any text, not just a letter. Going back to 25+ year old QuickDraw for text drawing and the CPU usage difference isn't even measurable no matter what I draw.

<RANT_TIME>

It still irks the crap out of me that multiple displays are done so poorly in OS X, where as in OS 7 to 9 back in the late 80's /  early 90's  with hardware that had 1/10 the CPU power and 1/100th of the GPU power, I could easily run 3 monitors on a single core 20 mhz 680xx Quadra when doing GIS demos at large oil conventions. Using QucikDraw3D's  (now Steve'd) retained mode, I was creating 3D models with textures and lighting, then saving them to disk and then letting people play with them in the simple QD3D viewer, which made the Silicon Graphics Guys cringe cause they were selling boxes that cost $250,000 plus and could not do this as easily.

</RANT_TIME>

Milton J. Aupperle