ps-print-color-p and the background colour of Emacs' frame

[Christian Schlauer]

Observed with Emacs 22.1:

- emacs -q --no-site-file

- M-x set-background-color RET LightSkyBlue RET

- C-u M-x ps-print-buffer-with-faces RET RET

If I open that file with a PostScript viewer (Evince in Ubuntu 7.04),
there is no background colour in the text area. If I now *repeat*

- C-u M-x ps-print-buffer-with-faces RET RET

and open the file again, you'll see that the background of the text
area is in the colour LightSkyBlue, too.

===> Why *isn't* the background colour in the file when it is saved
     for the first time? Bug?

Now do

- M-x set-variable RET ps-print-color-p RET nil RET

- C-u M-x ps-print-buffer-with-faces RET RET

Open the file: background is blue, but text is black. Now simply repeat

- C-u M-x ps-print-buffer-with-faces RET RET

Open the file: background is white, text is black.

===> Why *is* the background colour in the file when it is saved for
     the *first* time? It shouldn't, see the description of
     ps-default-bg below. Bug?

Now do

- M-x set-variable RET ps-print-color-p RET black-white RET

- C-u M-x ps-print-buffer-with-faces RET RET

Open the file: background is white, text is black and italic, as
expected. Now simply repeat

- C-u M-x ps-print-buffer-with-faces RET RET

Open the file: background is blue -- WHY?

===> Why *is* the background colour in the file when it is saved for
     the second time? Bug?

,----[ C-h v ps-default-bg RET ]

[...]

| The `ps-default-bg' variable contains the default background color
| used by ps-print, that is, if there is a face in a text that doesn't
| have a background color, the `ps-default-bg' color should be used.

[...]

| It's used only when `ps-print-color-p' is non-nil.
| 
| See also `ps-use-face-background'.
| 
| You can customize this variable.
| 
| [back]
`----