Typically, you have 4 work spaces on your monitor after you login into the CDE desktop. The background patterns on these work spaces are called backdrops. Behind the backdrop there is a single root window. You can place any type of image on the root window. This message will discuss various ways to change the background on the work places, as well as, on the root window.

Changing backdrops

In any workplace, you can change the backdrop by using the style manager (the one beside the printer icon). Double click the icon labeled backdrop. In the popup window, scan through the name list using the scroll bar and choose the one you want. The image will be displayed in the popup window. Click on Apply button, and it will be used as the backdrop.

Creating your own backdrop and sharing it with the rest of us.

The image of a backdrop must be in a bitmap file. You may use any application software to create your own bitmaps. Typically, you would use the image viewer to view an image and modify it, and then save it in XMP or Sun raster format. You can also use a program called bitmap to create a bitmap and save it in a file. A third way, is to use the xfig program to paint something, and then export it to an XMP file (you may do so by clicking on Export button then on the default export file type, then choose XMP format).

Suppose you have created a bitmap file newstuff. Test it as described below. Once you are satisfied with it, issue the following commands to make it publically available (faculty users only please):

`mv newstuff /home/dt/backdrops`
`chmod 644 /home/dt/backdrops/newstuff`

In order for you to access these locally available backdrops you must make a link to this directory in your .dt directory:

`cd ~/.dt ; ln -s /home/dt/backdrops`

Now you can change one of your backdrops to newstuff as described under "Changing Backdrops" above. However, you might need to restart your window manager. To do so, put the cursor on the current backdrop, press button3 (the rightmost one) and choose Restart Workspace Manager...

Alternately, you could have a personal set of backdrops in the directory ~/.dt/backdrops instead of linking to /home/dt/backdrops.

Placing an image on root window (and testing a backdrop)

Change the backdrop to one of your work places to the one named "Nobackdrop". This makes the backdrop transparent, so that you can see through to the root window. Start a terminal window and enter:

`xv &`

In the xv window, press button3 to get a control panel. Press the Load button to bring up a directory window. Choose any image file that xv can display. Xv can handle formats gif, jpeg, XMP, ... Load the file in. You now have the image on the xv window. Now press the Display button on the control panel and choose anything starting with the word root, and you should get the image on the root window.

Note that, the backdrop of the workplace is like a curtain on top of the root window. You can hide the root window image by change the backdrop to something other than Nobackdrop. You have four workplaces (more if you feel like making more instead of working ;-)) but only one root window. So if you make the backdrops of all workplaces transparent, all you see is the same background image in all your workplaces.

Automatic setup of the root window.

This is very easy. Just do the following:

`cd ~/.dt/sessions`

Edit or create a file called sessionetc and put a line in it that starts the appropriate image viewer. For example:

`xsetroot -fg yellow2 -bg green -bitmap /home/zhang/foo_bitmap`

or

`xv -root /pub/images/flowers/columbine.jpeg`

Then make sessionetc executable:

`chmod u+x sessionetc`

You will get the new root window image the next time you login.

-- Weining Zhang (zhang@cs.uleth.ca)