Why is window resizing so slow?

[TheSisko]

After one month with Mac/OS X, this is my biggest gripe with the system.
Even after upgrading to Tiger, resizing windows is still slower than any old crappy PC running Windows. I understand that this was even worse before (read some reviews saying it was "unusable" in 10.0.0), but still, even resizing an empty window is not "realtime", like it is Windows XP.
And sometimes it can be painfully laggy (like webpages with a lot of pictures). So my question is, how has this after 4 years still not been fixed? Is there some fundemantal architectural thing with OS X?

I mean moving windows around is über-fast (in fact, faster than Windows), scrolling is fast, Exposé is fast. Why is it so hard to resize windows fast???

 

[Applespider]

It's to do with how the two systems actually redraw the windows.

The Mac actually redraws every pixel as you stretch it (each one of those brushed metal pixels is redrawn) whereas Windows doesn't, it tricks the eye into thinking it's continuous but isn't, or draws the edges out but doesn't fill in the middle til you've finished - one reason why occasionally in Windows, the processing application doesn't update and leaves you with white spaces until it's finished.

I read an article that explained it all beautifully a while back. I'll post if I find it again.

 

[TheSisko]

I read an article that explained it all beautifully a while back. I'll post if I find it again.

That would be great, thanks! I'll have to say though...that I prefer the Windows way, feels more responsive.

 

[Desperado]

Yeah, but that can't be the only reason.
Windows Media Player for MacosX also only renders the borders while resizing
and it is still noticeabely slower than on Windows.
Also, Firefox on Windows has live-resizing too and it is still faster than
Safari, Camino or it's own MacosX Version.
Possibly it isn't the fault of the operating system but lack of optimization.
Resizing in Apple Mail for example is faster than in any other application
I have seen. Apps that use the original Aqua theme are faster than those
who use brushed metal. Scrolling with pdfs in preview is veeery slow,
although it got much better with Tiger. Camino with CoreImage support resizes
html pages that contain mostly images faster than Safari ( I don't know
if it uses CoreImage also).

What really irritates me is that it doesn't seem to run really smooth even
on highend G5 Macs.

 

[Lacero]

I wish Apple would speed up window resizing. I don't all too much for the icons of the left hand side of the Finder window to dynamically scale as I resize. In fact, I find it annoying. I'd just like a simple interface that doesn't beat me over the head constantly telling me to ooh and aahh at every feature it can do.

 

[TheSisko]

What really irritates me is that it doesn't seem to run really smooth even
on highend G5 Macs.

It really shouldn't take a fast cpu to accomplish this. Windows resizing on PC is fast even on a Pentium 200MMX, and that's WAY slower than any G4.

 

[stridey]

It really shouldn't take a fast cpu to accomplish this. Windows resizing on PC is fast even on a Pentium 200MMX, and that's WAY slower than any G4.

See above posts. Windows resizing is fast, but at the cost of consistancy throughout the GUI (ie empty windows).

 

[Desperado]

See above posts. Windows resizing is fast, but at the cost of consistancy throughout the GUI (ie empty windows).

Read my post. WMP9 uses empty frames on Macosx an even that
isn't 100% fast.

 

[Earendil]

Read my post. WMP9 uses empty frames on Macosx an even that
isn't 100% fast.

And you're going to use a Microsoft app as proof that MacOS isn't fast at redrawing windows? duurr.....

 

[cbiffle]

This has to do with how live-resize is handled in the OS X GUI.

In Windows, live resize is not handled. That is, each program must implement its own code to resize its controls. However, it's made relatively easy for the app author to notice that resize is in progress, and not do a lot of work. This is why in many apps, you can resize the window back-and-forth quickly, but the actual display (say, the web page you're viewing) won't conform to the new window shape until you pause or let go.

The Mac GUI layer handles live resize internally. However, until recently, there was (1) a known bug in the GUI code that made resizing slow even if you worked to make it otherwise, and (2) no real support for developers to speed up the process. It was difficult to detect when a resize was in progress, so most apps would e.g. recalculate all the web page layout for each movement of the mouse. Slow. (This primarily affected Cocoa apps, fyi; Carbon developers had a way around this, but many chose not to use it. And don't get me started on the Finder. )

On Tiger, Apple has made some changes to the GUI layer to speed up live resize. On my G5, Safari still lags a bit behind the mousepointer (which I consider unacceptable) but it's better than it was on Panther.

So:
1. Apple recognizes the problem and has been working on it.
2. Application developers, as of Tiger, now have the ability to detect live-resize and speed up (generally simplify) their drawing.

So the situation should improve. I hope.

 

[runninmac]

I noticed that today when I was at the apple store even with the Dual 2.7 GHz (not very noticeable). Well mabey most of it was because it was running the HD Trailers at full screen on a 30inch!