The curve editor opens after double clicking a curve field.
File in the top left loads or saves a curve.
Below that there is the field Position that shows the x- and y-position of the mouse if the mouse is over the editor field. Otherwise and if there is a point selected in the curve field, the position of this point is displayed. It can be edited by typing, too.
You can also select more than one point in the editor field. Ctrl (Windows) or Command (macOS) adds a single point to the selection, Shift selects ranges.
The buttons in Actions are offering the following functions:
Delete point: You can delete the selected curve point with this function.
It is not allowed to delete the first or the last point of a curve.
Shift to the top, the bottom, the left and the right: The
curve is shifted to the direction of the arrow.
Neutral: You get a standard curve with a 1:1 mapping.
Mirror: The curve is mirrored on the horizontal mid line.
Stairs: This button creates a stairs looking curve. The text field beside
the button specifies the number of stairs.
The combo box in the bottom left specifies the editing mode. Possible values are Manual, Line, Spline, Bezier, Bezier2 and Lagrange. With Manual you can simply draw the curve. With Line you can move the end points of lines, Bezier and Lagrange are curve types where you can move the control points. By holding the Shift key, you can restrain the movement to vertical. Additionally you can create new curve points in this modes by clicking on the curve line. You can see that it is possible to create points by watching the mouse cursor as it becomes a small cross.
There is a manual text input, too. Here you can enter the curve in 5% steps. These values define a manual curve.
At the bottom edge of the curve editor is a list field which contains already predefined curves. You can drag curves from the large curve field to this list field. All curves in this list field are automatically in the curve list (see chapter 4.19).