You can change the position of a graphical region's viewport, or of all the viewports in a class, with the change position action statement. The coordinates are specified as positive or negative integer values in the coordinate system of the region's parent.

 

The change position by statement changes the relative position of the graphical region's window. For example, suppose you move the viewport, from its defined position of 225 150 on the screen, to the right, as shown below:

 

response to ChangePos

    change Blackboard position by 25 0

 

You now see the following:

 

The contents of the viewport are exactly the same, because the window is unchanged and the size of the viewport is not affected. The viewport, however, appears farther right on the display. Its lower left corner is at coordinate position 250 150.

 

The change position to statement changes the absolute position of the viewport. For example:

 

response to ChangePos

    change Blackboard position to 0 0

 

moves the viewport to position 0 0 on the display screen. The viewport and its contents are shown below. Again, the contents of the viewport have not changed.

 

 

For information on how the change position action statement affects textual regions, see Changing the Size and Position of a Textual Region's Window and Viewport.