The darktable.gui.action() command uses the following syntax:

darktable.gui.action(
  path : string,
  [instance] : integer,
  element : string,
  [effect] : string,
  [speed] : integer
)

To quickly capture the default command for a specific UI element:

• switch to the mapping mode for shortcuts
• hover over the specific UI element (button, slider, combo box, etc.).
• Once the tooltip is shown, perform long right-click to copy the default command to the clipboard.

In this example, the default command is

dt.gui.action("lib/export/set size", "selection", "item:in pixels (for file)", 1.000)

with the following parameters:

• Path : "lib/export/set size"
• Element : "selection"
• Effect : "item:in pixels (for file)"

While the steps above provide the default command, the element and effect parameters often support alternative values. To identify all available options for a specific path, proceed as follows:

1. Go to the shortcuts section in the preferences module and locate the item you want to manipulate

2. Assign a shortcut to it and select it

3. click on the fields to see what's available