How to add a y = x reference line in Graph Builder without creating a new column?

[#1]

Hi,

I’m trying to add a reference line like y = x in Graph Builder, but I’d like to do this without creating an additional column.

I know I can add constant reference lines (e.g., y = 100), but I couldn’t find a way to directly input a function like y = x or y = ax + b.

Is there any way to add a function-based reference line directly in Graph Builder?
Or is using a new formula column or a graphics script the only option?

Thanks in advance!

[#2]

Y Function()

Some examples for example here (right click on graph > customize > +)

[#3]

You can easily create a virtual column in Graph Builder and then use it in the graph.

Right click in the Column selection window and select "Formula". 

Set the formula to the column that is going to be your X column in the graph

Click OK and your new virtual column will be displayed

Now just drag you X column to the X drop area, and your Y column and the new virtual column to the Y drop area and you will have your graph.

[#4]

Adding to @txnelson's suggestion, note that you can rename the formula column (right click the name after building it), and then add a line chart element (right click in the graph space, add, line), and then hide the points on the 1:1 line and hide the line on the x variable (see screenshot) so you get a clean looking graph:

[#5]

Here a script to do it for a single frame chart