WallPaper is a BackSpace module that is an encapsulation of the wallpaper.ps program (gradient wrapping paper, symmetry group P4M) that Elizabeth Zwicky <zwicky@erg.sri.com> submitted to comp.sources.postscript.  (See enclosed comp.sources.postscript.87 file for the original posting and program.)

WallPaper provides sliders on the BackSpace Settings panel to control the wildness of the images, as defined in the original PostScript program, and the brightness of the colors.  (There are other defaults you can adjust listed below.)  The program continuously dissolves from one output of the wallpaper.ps program to the next.

There are some modifications that Elizabeth suggests (and provides alternative possibilities) in the comments to her program.  If you want to experiment with these, I suggest you unshar (or edit out the headers and execute the body using csh/sh) the comp.sources.postscript.87 file to extract the original wallpaper.ps program and try the various modifications using Yap (unfortunately Preview doesn't execute this program in color).  Once you settle on something you like, make the same modifications to the WallPaperWrap.psw file, which is nearly identical to wallpaper.ps but much less interactive for experimentation, and remake the module.

WallPaper was built and tested with the NeXTSTEP 3.0 version of BackSpace and may be incompatible with earlier versions.

Installation

To install WallPaper, copy the WallPaperView.BackModule bundle (directory) into the ~/Library/BackSpaceViews or /LocalLibrary/BackSpaceViews directory.  The following will install WallPaper in your ~/Library/BackSpaceViews directory:

make install

Or you can specify the installation directory:

make install INSTALLDIR=/LocalLibrary/BackSpaceViews

Or use 'cp -r' or tar to move the file to the desired location.

Defaults

WallPaper has several defaults that you can set by doing a dwrite to the owner BackSpace  (the first two can also be set from sliders in the BackSpace Settings panel):

	WallPaperWildness ( = "0.5" )

Possible values for this default are 1, .5, 0, -.5 and -1.  (According to the original program, in monochrome .5 and 0 are hard to tell apart.)  The setting varies from psychedelic at 1.0 to slightly more tame at lower settings.

	WallPaperBrightness ( = "0.5" )

This puts a damper on the brightness of the colors so that in addition to a constantly changing screen image, you don't have one that's too bright to be a good screen saver.  The setting ranges from 1.0, full brightness which is great for showing off color machines, to 0.0 which is pitch black. 

	WallPaperStep ( = "0.1" )

Ths default is the step size used in dissolving from one image to the next.  Its range is between 0 and 1.

	WallPaperCount ( = "4.0" )

Ths defaults controls how many repetitions (horizontally) you'll see on the screen.  Since screen height to width is typically a ratio of 3:4, multiples of 4.0 work best but you can adjust to your screen setup.  Unlike the above defaults, this is only checked at initialization and won't affect WallPaper once running.

Christopher_Lane@Med.Stanford.EDU