faster screen redraw in recent ver HD for OS X

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Michel PM
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Joined: Wed May 05, 2004 12:34 pm
Location: Western Massachusetts, USA

faster screen redraw in recent ver HD for OS X

Post by Michel PM »

I have noticed that recent HD realease for OS X is faster, but still slower on redrawing than on OS 9.
I usually have the grid active and showing with anti-aliasing on. I know hiding the grid when I do not need it speeds up redraw, somewhat. So, I toggle this on/off as needed.
Anti-aliasing really helps to render much more accurate geometry on screen. So, I really would not prefer to disable this,either.
Any other suggestions for speeding up the redraw on OS X would be welcome.

Mac is a beige G3/G4 1.0ghz upgraded CPU, 768 Mb RAM, 60 Gb HD
Video is running through an ATI Radeon 7000 on a LaCie DVI flat panel LCD (DVI out)

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Andrew
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Post by Andrew »

The differences of speed between Classic and OS X versions aren't specific to HighDesign. Many other applications had similar problems when ported to the "new" system.
The main reason is that the new threading model in Mac OS X does not allow applications to take full control of the processor. In OS 9, an application could use almost all CPU time for its calculations, resulting in faster processes within a fragile system.
OS X does not allow this: processes can't use 100% of CPU time because the system distributes the processor time ("cycles") among all of the other running processes, so that you can always switch between open applications and have them complete their tasks at the same time.
However, there are areas where OS X is much faster than Classic: for instance, accessing the disk to read and write files is a lot faster now.

As for HighDesign redraw speed, antialiasing is a key factor: Quartz (the graphic engine in OS X) is slower if compared to QuickDraw (which isn't a fair comparison, I know), but that's because it actually does a lot more work. If you don't want to turn off antialiasing, there are some other options, though they might not be as effective:
- don't use patterns or pictures for the background of the main window
- hide the grid or change its linetype from dotted to continuous
- delete unused layers
- use hairlines instead of bitmap penweights (Preferences > Drawing)

We are constantly optimizing HighDesign though, and there are even more optimizations planned for the future that will make it faster.

Hope this helps.

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