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Why do slow mouse movements skip pixels?
- Thread starter ToastyX
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I'm not saying that they don't, but in 17 years of Mac use, I've never noticed this, and I can't say I'm really seeing it when I try it right now--the pointer just seems to sort of zigzag at an angle, as it can't (or, I suppose, doesn't) move at a diagonal, only horizontally or vertically.
Is there some particular reason this is an issue for you? How did you even notice it?
Is there some particular reason this is an issue for you? How did you even notice it?
ToastyX said:
My guess is that it is an artifact of rounding errors. The cursor can only be drawn at position X,Y where X and Y are whole numbers. To truely move the cursor along a diagonal line (other than 45 degrees) or a circle requires a continuous rather than discrete grid.
This is exactly the same reason why diagonal lines and circles are more like steps rather than a line or circle. That is if anti-aliasing is not used.
This is an issue for me because it makes freehand drawing with the mouse harder to do, and it affects accuracy in games.Makosuke said:
I don't know how I notice it. I just do. I can see it happening. It's obvious to me after being used to smooth mouse movement in Linux, Windows, and DOS for so long. I guess I'm just very sensitive to detail.
I know what you mean, but that's not what I'm talking about.mrichmon said:
It becomes very obvious when trying to draw circles or diagonal lines in paint programs. It happens with any mouse I try, including Apple's one-button mouse, but only in Mac OS X. To demonstrate this, I tried drawing a couple of circles and a diagonal line using both a Logitech mouse and Apple's one-button mouse on both my Power Mac G5 and my Linux machine with The GIMP 1.2.5 on both machines.
The results speak for themselves: http://www.toastyx.net/images/mouse.html
As you can see, the problem is not with the mouse. I know the problem is not with something I have installed because I can also see it happening when booting from the Mac OS X install disc that came with my computer. I know the problem is not with my computer because later I downloaded and booted an Ubuntu live CD, and the results were similar to my Linux machine. That means the problem is with the way Mac OS X handles mouse movement, and that bothers me because it shouldn't be happening. Why does it do this?
Does anyone else notice this?
I've noticed it a few times but it doesn't really bother me all that much. If I had to choose between the mouse not moving perfectly while using OS X or that mouse moving perfectly and using XP, I'll take OS X everytime.ToastyX said:
ToastyX said:
I doubt that you mean smooth mouse movement in DOS given that MS-DOS only provided a text-based command-line interface.
ToastyX said:
Interesting results.
The aliasing problem still exists on the input side. The problem is the same as with drawing diagonal lines and is related to conversion from continuous data to discrete data. In more detail, I suspect the issue is in how the Apple mouse driver does the conversion from the device readings to the cursor movement. You can notice the effect a little more strongly if you turn on screen zooming via the accessibility preferences and zoom in a few levels by pressing command-option-+.
I'd suggest you submit a bug report to Apple about this since it appears that their translation algorithm is less smooth than the competition.
Using an Intellimouse, I get results similar to your Linux ones. I don't see that problem on OSX at all. Have you installed proper drivers for the mouse you're trying to use? Or are you perhaps using the generic drivers built into the OS?
Well, I meant DOS programs.mrichmon said:I doubt that you mean smooth mouse movement in DOS given that MS-DOS only provided a text-based command-line interface.
I see it happening with the built-in driver as well as with Logitech's software and USB Overdrive. Perhaps they only control the built-in driver. I've read that Microsoft's driver works differently, but that requires a Microsoft mouse. I do have a Microsoft mouse laying around somewhere. Maybe I'll test it later just to see the results, but I'd rather use my Logitech mouse.DannySmurf said:
I had exactly the same problem and it turned out to be a bad usb port, plug the mouse in another and see what happens. If it doesn't work it might be a corrupted driver inside the OS, i know you hate to reinstall but most of the times it takes away all problems.
jayscheuerle
macrumors 68020
Looks like a information delivery problem, like the mouse in OSX isn't being sampled enough times per second.
I must say this REALLY is one of my major annoyances with OSX compared to XP. For me, the mouse is behaving in a rather erratic way, especially when going on and off the dock it seems to slow down and jump like it's on a rubber cord, incredibly annoying. I was thinking about making a thread of it, perhaps I will.
Also i noticed that under OSX it seems when you move the mouse slowly it moves slower then you'd expect, while when you move it faster it really jumps from one side to the other. I tried to play with the settings of the mouse but nothing really satisfies me
Also i noticed that under OSX it seems when you move the mouse slowly it moves slower then you'd expect, while when you move it faster it really jumps from one side to the other. I tried to play with the settings of the mouse but nothing really satisfies me
Coheebuzz said:
That's one of the first things I tried before I realized it was a Mac OS X problem. It happens no matter what USB port I try. Besides, if the USB port was bad, then it should have happened when booting from the Ubuntu live CD as well, but it was smooth under Linux.
If it's a corrupted driver, then it shouldn't happen when booting from the Mac OS X install disc, but it does. Besides, I have reinstalled for other reasons, and the problem has always been there.
minimax said:Also i noticed that under OSX it seems when you move the mouse slowly it moves slower then you'd expect, while when you move it faster it really jumps from one side to the other. I tried to play with the settings of the mouse but nothing really satisfies me
That's acceleration, which isn't necessarily a problem, but many people find the mouse hard to control when the acceleration is too strong.
From what I can tell, the built-in mouse driver seems to take the native speed of the mouse and divides it by four, then applies acceleration. If you have a 400 DPI mouse or a mouse that defaults to 400 DPI, this can be quite slow. So what do most people do? They increase the tracking speed setting. The problem is the tracking speed setting doesn't really control the tracking speed. It controls the acceleration, so when they increase the tracking speed setting, they're making the acceleration stronger, thus making the mouse harder to control. This is what many people don't like.
The only way to control the tracking speed is to use a third-party program like USB Overdrive. Try setting the speed to 200 DPI and the acceleration to 50%. That will double the tracking speed but give you the default acceleration. I bet you'll find the mouse much easier to control. If not, play around with it and see what works best for you.
This is an irritating phenomenon. I always thought it was the surfaces I was using my mouse on (which it still might be), but it's intriguing to know that other users are experiencing similar difficulties. My Kensington likes to get stuck on axis, so when I draw a circle it takes special effort to keep the sides from becoming stepped parallel and perpendicular lines.