Wednesday, June 1, 2011

Fix for Scroll Issue with Picasa 3.8 on Windows 7

Recently I faced a strange issue with picasa, the photo organizer/editor from Google. The scroll does not work !!, It was working perfectly fine on my personal laptop, but was not working on my office laptop, and scroll works fine in rest of the applications. I was thinking there is something to do with the installation, but reinstall also did not solve the problem,

Later I found that, Most (almost all) mouse drivers cause mouse wheel events with a "delta" of ±120. This is an arbitrary value that has been choosen by Microsoft in the past to allow finer control.

Since then, several programs use that value directly to test whether the mouse has been scrolled down or up (delta / 120 == 1 -> down, delta / 120 == -1 -> up, or something like that).

However, the Intellipoint software causes mouse wheel events with smaller "delta" value (the expected finer grain control), and programs which use the 120 value that way just fail to register the wheel movement, because in integral values, 30 / 120 = 0...

Let's hope Picasa developers would fix this issue soon, by modifying the mouse wheel handling method.

There are ways you can fix this issue temporarily, one is by using the Autohotkey. Autohotkey is a program you run in the background, which loads simple or complex scripts controlling the mouse and keyboard inputs, as well as other wanted behaviors in your Windows system. You can intercept the mouse wheel event and change the delta value before passing to a particular program, so if you make it 120 again, you would solve the issue.
  1. Download and install AutoHotkey (
  2. Right-click an empty spot on your desktop or in a folder of your choice.
  3. In the menu that appears, select New -> AutoHotkey Script. (Alternatively, select New -> Text Document.)
  4. Type a name for the file, ensuring that it ends in .ahk. For example: Test.ahk
  5. Right-click the file and choose Edit Script.

In the window that appears (likely Notepad), copy the lines of the script above. Save your document.

AutoHotkey does not run by itself, it runs a script. So you need to put the script file you just created in Startup, and it will start automatically when Windows start. This should fix your mousewheel problems with Picasa.

I have found that the latest IntelliPoint 8.0 software (released August 2010) fixes the scrolling issue. It also does the same thing, it detects that the picasa is running and changes the delta value to 120 and things would work just perfct

You can download the latest version of Intellipoint software for your mouse from here,

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