Understanding AutoHotkey %Var% Variable Text Replacement (AutoHotkey Tip)

Handy Window Transparency Wheel Using Macro Replacement Quickly Peeks Under a Window without Moving It, Plus the Difference Between % Var and %Var% Made Easy

The AutoHotkey online documentation goes into great detail about the traditional method for retrieving values from variables (%Var%) and the force expression evaluation method (% Var). It can take the new AutoHotkey user a little while to comprehend the differences between the two. In an effort to clarify the variations and help beginners to understand when to use which method, I offer an alternative way to view the operations. For the traditional method, I prefer using the terms macro substitution or variable name replacement. Once, you understand how it works, differentiating when and how to use each technique becomes easy.

The value-added trick comes when creating variables containing new variables on-the-fly by combining the two methods (i.e. forcing an expression % which contain a %Var% variable name replacement). The first step involves replacing the variable with its value, the new variable name (%Var%). The second step requires the forced evaluation of the new variable (% VarValue) as part of an expression.

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Volume Control
Volume Wheel

A while back I installed a volume control operated by the mouse scroll wheel. Simply hover over the Windows Task Bar and scroll the mouse wheel up or down to adjust the PC speaker volume level higher or lower, respectively. A progress bar (shown at right) pops up displaying the changing volume level. I’ve added this convenient tool to my standard AutoHotkey script and use it all the time.

Tranparency Menu
Transparency Menu

At a later date, while playing with window visibility, I set up a menu for changing the transparency level for the active window (shown at left). At the end of that blog, I suggested, “If you want to get really fancy, then you might use the mouse wheel to set the transparency (or opaqueness) level.” I’ve done just that with my new SeeThruWinWheel.ahk script. Now, by holding down the CTRL key while scrolling the mouse wheel, the window under the mouse cursor becomes less opaque (WheelDown) or more opaque (WheelUp). In the course of writing this short script, I implemented a number of AutoHotkey tricks worth discussing. Continue reading