PostScript Landscape Mode

QUESTION: My plot disappeared when I selected PostScript landscape mode. What happened?

ANSWER: Setting PostScript offsets in Landscape mode is non-intuitive (to say the least). If you don't know this, you're landscape output can disappear!

In portrait mode, the point from which PostScript window offsets are calculated is the lower-left corner of the page. The X offset is calculated left-to-right in the direction of the X size of the plot. The Y offset is calculated bottom-to-top in the direction of the Y size of the plot.

In landscape mode, the point from which the offsets are calculated is rotated along with the PostScript page. In practice this means that the X offset is calculated bottom-to-top in the direction of the Y size of the plot, and the Y offset is calculated right-to-left in the direction of the X size of the plot!

Here is a picture of the landscape offset situation.

If you were in the habit of setting the offsets to, say, 1 inch in both the X and Y directions for Portrait mode printing, you could easily rotate your graphic off the PostScript page by using offsets of 1 inch in Landscape mode. In other words, your plot can disappear.

One reason I like to use the program PSConfig to get the sizes and offsets of the PostScript output window is because it shields the user from this type of non-intuitive interface. In PSConfig the offsets are always calculated from the lower-left corner of the page, whether in Portrait or Landscape mode.