If you have a laptop that supports multitouch gestures, you probably are aware of the fact that a three-finger swipe in Preview will go to the next or previous page in a PDF. But you may be annoyed at how Preview insists on animating each page switch with a small scrolling action. This can make it very slow to scroll through a document -- almost as slow as regular two-finger scrolling.

Fortunately, there is a solution: use a three-finger swipe in the sidebar. When you swipe in the sidebar, the pages will change instantly, without any animation. This works no matter what mode the sidebar is in (table of contents or thumbnails). And if you are in contact sheet mode, three-finger swiping will navigate you through the contact sheet.

I can only test this in 10.6, and I didn't discover it until I was running 10.6, so I don't know if it works in 10.5 or not.

[robg adds: My MBP is also 10.6-only now, so I can't test in 10.5 either. If you can, please post in the comments.]

Many iBook G4 laptops (and possibly other models) have a problem with the inbuilt AirPort card failing, and then causing regular kernel panics. This can be avoided in Leopard, and possibly Tiger, by replacing the kexts responsible for the AirPort with dud files like so:

1. Quickly turn off AirPort in the menu bar after turning on the laptop.
2. Open TextEdit and save two blank files to the desktop. The first is called IO80211Family.kext.rtf and the second is AppleAirPort.kext.rtf. Then go to the Desktop and remove the ".rtf" extension, and approve the change to a kext extension.
3. In Finder, go to System » Library » Extensions, delete the files AppleAirPort.kext and IO80211Family.kext and authorize the action. Then drag the two 'dud' kext files from the Desktop into the Extensions folder, and again authorize the action.
4. Restart the laptop.

You should see that kernel panics just aren't happening -- the Airport card won't be recognised in System Profiler, and the laptop can be used as normal with the aid of a USB wireless adapter. This blog post explains the process in more detail.

I noticed that recently the volume on my MacBook Pro has been seriously reduced, sometimes to the point of being almost inaudible. Where it's really noticeable is when I rent a movie from iTunes, then try to watch by hooking my MBP to my HDTV via mini Display Port to HDMI, and headphone jack to the input on my audio system.

Lately, even with all volume controls turned to max, it's still almost impossible to hear the movie. The answer, according to tips I found via Google, is to run Audio Hijack Pro and hijack iTunes audio. Boy, does this work. Using the gain controls available within Audio Hijack Pro, you can blast the sound with the various volume controls turned almost all the way down. The leading theory is that Apple deliberately reduced the level of audio reaching the speakers to avoid damage when booted into Windows, which apparently drives the speakers much harder.

Anyway, I can watch movies again and finally hear what's going on. The problem now is that, for some reason, setting iTunes to full-screen with Audio Hijack Pro running puts the movie on the MBP's screen, which obviously isn't what I want. The workaround I found is to go to the Displays prefpane and drag the menubar to the HDTV. Kind of annoying to have to do this, but at least it works.

After upgrading to Snow Leopard, I found that I can change the icon size in the Finder's Icon view windows using the MacBook's multi-touch trackpad. To do so, just use a two-finger zoom/pinch gesture to either zoom in or out -- this works on the Desktop, or in an active Finder window in Icon view mode.

[robg adds: I was hoping this might also work to change the text size in List and Column view modes, but no luck. It only works in Icon view mode.]

As far as I know, the Unibody Macbook Pros (and probably most MacBook Pros) ship with 85 watt power supplies. Unfortunately, a lot of in-seat power ports on airplanes are limited to 75 watts, and plugging in your 85 watt power supply will quickly overload the power supply. This is not dangerous to the plane or anything, but the power will shut off.

There are two options. First, run your MBP off of the battery, then when the battery dies, close the lid and recharge the battery in sleep mode, as this will draw much less power than running the machine and charging the battery.

Also, and this is a little dangerous to your work, remove the battery and run solely on the in-seat power. With the battery removed, no power will flow to the battery and you'll be able to run at on the 75 watt power from the seat. But ... be careful, save often, and I'm not responsible for the consequences. Consider if the guy next to you bumps the plug and it falls out -- your machine will go off!

I am not an electrical engineer, but these options worked for me. I would appreciate feedback from any EE types on how bad of an idea this is...

The iBook G4 (and various other iBooks) do not support "spanning" dual displays (I believe Apple calls this feature "extended desktop") with Leopard or Snow Leopard. Evidence of this is the missing Arrangement tab in the Display System Preferences panel.

The Tiger version of Spanning Screen Doctor does, indeed, work correctly on an iBook G4 running 10.5.4. After rebooting, the Arrangement tab will now appear in the Display pane.

Hopefully this saves some iBook users some time and effort in resolving this issue.

[robg adds: We covered this app many years ago, but I thought it was worth an update for both newer hardware and newer OS versions.]

One of my biggest complaints is not having the ability to toggle Bluetooth on and off based on my power source. I use my Macbook in clamshell mode, so turning Bluetooth back on with my Bluetooth keyboard and mouse is impossible. I have to wait for my Macbook to wake up, open the lid, and reach over to the trackpad and toggle Bluetooth on.

With some help, I was able to make the following script to toggle Bluetooth on when the machine is plugged in, and off when running on the battery. This script is smart in that it will not fight you if you turn Bluetooth on while on battery power. You can unplug the power, the script will turn Bluetooth off, and you can turn it back on and it will stay that way.

There is one requirement to use this application which is blueutil. (I have it mirrored on my site where I originally posted this; you can see my full guide there as well). Here's the script (remember to make it executable):

#! /bin/bash
PREVIOUS_SOURCE=$(pmset -g ps | perl -ne '/(w+) Power/ && print $1');

while [ 1 ]; do
  CURRENT_SOURCE=$(pmset -g ps | perl -ne '/(w+) Power/ && print $1');

  if [ $CURRENT_SOURCE != $PREVIOUS_SOURCE ]; then
    PREVIOUS_SOURCE=$CURRENT_SOURCE
    if [ $CURRENT_SOURCE = "AC" ]; then
      blueutil on
    else
      blueutil off
    fi
  fi
  sleep 5
done

Next you simply need to run the script at startup, which is easy enough to do with the free app Lingon.

I have not noticed any memory leaks, and this only uses about 600KB of RAM to run with almost no CPU usage to call on pmset or blueutil. You can obviously change the sleep setting (which determines how long before the script runs again) to whatever you like.

[robg adds: I haven't tested this one.]

I was quite annoyed with the sound quality of my Santa Rosa MacBook, i.e. a MacBook3,1. I had upgraded to this machine via a hard drive swap from the first generation Macbook, and now there was much noise on the headphones.

Today I found out that I can get perfectly fine audio by starting Audio MIDI Setup (in Applications » Utilities) and selecting 2Ch-20bit (or 24bit) for the headphones, instead of the previous 16bit setting.

If "tap to click" is enabled and suddenly stops working, a quick cycling of the option will fix the problem without rebooting. System Preferences » Trackpad » Tap to Click.

Uncheck then re-check, and the problem will be fixed.

I found a solution to why my laptop fan was running constantly and running my battery out in an hour. This problem is common for MacBook users and many websites and forums suggest restarting, installing fan regulation software, resetting PRAM, etc. None of these really work, but the solution is very simple.

Since laptop users are mobile, they're frequently using different printers. When sending a document to print sometimes my MacBook selects the wrong printer, when it doesn't print I select a new printer and print again. But I forgot to delete the print job sent to the first printer, so my Mac keeps looking to print at the other printer causing the processor to heat up and the fan runs constantly.

Therefore, open System preferences go to Print & Fax, then select the printer that has a document in the queue, delete the print job and the fans shuts off within a minute -- and stays off.

The laptop will stay quiet and cool, the battery will last the usual amount of time, and MacBook mobile life is good again.