only build ppmviewer on colour targets (as it doesn't do greylib yet), and actually document it

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17895 a1c6a512-1295-4272-9138-f99709370657

apps/plugins/SOURCES

@@ -55,12 +55,15 @@ text_editor.c
 wavview.c
 robotfindskitten.c
 
+#if HAVE_LCD_COLOR
+ppmviewer.c
+#endif
+
 /* Plugins needing the grayscale lib on low-depth LCDs */
 fire.c
 jpeg.c
 mandelbrot.c
 plasma.c
-ppmviewer.c
 
 blackjack.c
 bounce.c

manual/plugins/main.tex

@@ -117,6 +117,8 @@ the associated file. Viewers are stored in the
 
 \opt{lcd_bitmap}{\opt{swcodec}{\input{plugins/mpegplayer.tex}}}
 
+\opt{lcd_color}{\input{plugins/ppmviewer.tex}}
+
 \opt{recorder,recorderv2fm,ondio}{\input{plugins/rockbox_flash.tex}}
 
 \opt{recorder,recorderv2fm,h1xx,m5,lcd_color}{\input{plugins/rockboy.tex}}

manual/plugins/ppmviewer.tex

@@ -0,0 +1,11 @@
+% $Id$ %
+\subsection{PPM viewer}
+Open a PPM file in the \setting{File Browser} to view it.
+
+ppmviewer exits when any button is pressed.
+
+\note{
+Both ASCII PPM (P3) and raw PPM (P6) files are supported.
+
+For more information about PPM files, see \url{http://netpbm.sourceforge.net/doc/ppm.html}
+}