Chapter 22: Page 417 - 'Manipulating a ScrollFrame'
In the printed text following "You can use these methods to center the image..." the text is somewhat confusing. The following should be used instead.
You can use these methods to center the image, using the following scripts in-game:
/run ScrollFrameTest:SetHorizontalScroll(-50)
/run ScrollFrameTest:SetVerticalScroll(50)
Note that the horizontal scroll requires a negative value in order to scroll the child to the left, and the vertical scroll takes a positive number to scroll the child up. This is consistent with the way coordinates in the user interface work, where (0,0) is the bottom-left corner of the screen. Figure 22-4 shows the frame when adjusted using these commands.