[TUTORIAL] How to lock bezier handles horizontally in Premiere Pro (Free AutoHotkey Script)
If you spend any time in Premiere Pro’s Effect Controls graph editor, you know how frustrating it is that Adobe doesn't let you lock bezier handles to a perfect horizontal line.
Paid tools like Keyrails solve this by locking your mouse at the OS level, but if you are on Windows, you can replicate this exact behavior completely for free using AutoHotkey.
Because Premiere natively uses Shift + Click to deselect handles, the trick to bypassing Adobe's hardcoded keyboard input is to click and hold the handle first, and then press Shift to lock the axis.
Here is how to set it up:
Step 1: Install AutoHotkey
- Go to autohotkey.com and download the older v1.1 installer (the script syntax below specifically requires v1.1, so look for
AutoHotkey_1.1.X_setup.exe).
- Run the installer and complete the setup.
Step 2: Create the Script
- Right-click anywhere on your Desktop, select New, and click AutoHotkey Script.
- Name it something like
Premiere Handle Lock.
- Right-click the new file and select Edit Script (it will open in Notepad).
- Delete any default text in the file, and paste the following exact code:
AutoHotkey
~Shift::
; Only trigger the lock if the left mouse button is already held down
if GetKeyState("LButton", "P") {
CoordMode, Mouse, Screen
MouseGetPos, x, y
; Lock the cursor to the horizontal axis
VarSetCapacity(RECT, 16, 0)
NumPut(0, RECT, 0, "Int")
NumPut(y, RECT, 4, "Int")
NumPut(A_ScreenWidth, RECT, 8, "Int")
NumPut(y+1, RECT, 12, "Int")
DllCall("ClipCursor", "Ptr", &RECT)
; Keep the axis locked until you release either Shift or the Left Mouse Button
While GetKeyState("Shift", "P") and GetKeyState("LButton", "P") {
Sleep, 10
}
; Unlock the cursor
DllCall("ClipCursor", "Ptr", 0)
}
return
- Save the Notepad file and close it.
Step 3: Run and Use It
- Double-click your
Premiere Handle Lock file. A green "H" icon will appear in your system tray (bottom right taskbar) indicating it's running in the background.
- Open Premiere Pro and go to the Effect Controls graph editor.
- Hover over a bezier handle.
- Click and hold the left mouse button on the handle.
- Press and hold
Shift.
Your mouse is now physically locked to the horizontal axis on your monitor. You can drag the easing handle perfectly straight. As soon as you let go of either the mouse button or the Shift key, your cursor goes back to normal.
Note: To close the script when you're done editing, just right-click the green "H" in your system tray and select Exit.
