doc/filters: add basic crop examples

Use it to show difference between shorthand and named parameters.

diff --git a/doc/filters.texi b/doc/filters.texi
index 7e3c7b9affe685fe9d67d47dde0cf28b055fc381..794fd473456e23a96e931230a9b0d74b75b9824a 100644 (file)
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -1612,6 +1612,17 @@ for @var{y} may depend on @var{x}.
 
 @subsection Examples
 @itemize
+@item
+Crop area with size 100x100 at position (12,34).
+@example
+crop=100:100:12:34
+@end example
+
+Using named options, the example above becomes:
+@example
+crop=w=100:h=100:x=12:y=34
+@end example
+
 @item
 Crop the central input area with size 100x100:
 @example