Add viewports to the manual. Adapted from FS#9934 by Jonas Häggqvist and FS#10553 by David Kauffmann
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22756 a1c6a512-1295-4272-9138-f99709370657
diff --git a/manual/advanced_topics/viewports/grayscale-conditional.tex b/manual/advanced_topics/viewports/grayscale-conditional.tex
new file mode 100644
index 0000000..390a043
--- /dev/null
+++ b/manual/advanced_topics/viewports/grayscale-conditional.tex
@@ -0,0 +1,15 @@
+\begin{example}
+ %?C<%Vda|%Vdb>
+ %Vl|a|10|10|50|50|-|-|-|
+ %Cl|0|0|50|50|
+ %C
+ %Vl|a|0|70|70|14|1|-|-|
+ %s%acThere you have it: Album art.
+ %Vl|b|20|14|50|14|1|2|-|
+ %t1%acWarning:;%t.1
+ %Vl|b|20|30|50|50|1|-|-|
+ %sNo album art found
+ %scheck your filenames.
+\end{example}
+This example checks for album art. Album art will be displayed in viewport 'a', if
+it is found. Otherwise a flashing warning will be displayed in viewport 'b'.