Evas doc: Add example for padding_set (filters)

With preview and all.

doc/previews/Makefile.am

@@ -39,7 +39,7 @@ DATADIR = ${abs_top_srcdir}/doc/previews/img
 HTMLDIR = ${abs_top_srcdir}/doc/html
 
 PREVIEWS = blend blur bump curve grow mask transform \
-example_1
+example_1 padding
 
 previews-data: preview_text_filter
 	$(MKDIR_P) $(DATADIR)
@@ -48,6 +48,7 @@ previews-data: preview_text_filter
 		echo "  GEN      filter_$${a}.png" ; \
 		FONT="Sans" ; \
 		SIZE=24 ; \
+		TEXT="TEXT" ; \
 		FILTER=`cat ${top_srcdir}/src/examples/evas/filters/filter_$${a}.lua` ; \
 		if [ -e ${top_srcdir}/doc/previews/filter_$${a}.sh ] ; then \
 			source ${top_srcdir}/doc/previews/filter_$${a}.sh ; \

src/examples/evas/filters/filter_padding.lua

@@ -0,0 +1,7 @@
+fat = buffer ('alpha')
+padding_set ({ l = 10, r = 20, t = 15, b = 25 })
+fill ({ color = 'black' })
+fill ({ color = 'darkblue', l = 2, r = 2, t = 2, b = 2 })
+grow ({ 30, dst = fat })
+blur ({ 40, src = fat, color = 'white' })
+blend ({ color = 'darkblue' })

src/lib/evas/filters/evas_filter_parser.c

@@ -1527,6 +1527,16 @@ _padding_set_padding_update(Evas_Filter_Program *pgm,
   A common use case will be when changing a blur size during an animation, or
   when applying a mask that will hide most of the (blurred) text.
 
+  Example (the @c fill command is used for illustration purposes):
+  @verbinclude filter_padding.lua
+
+  This will set the left, right, top and bottom paddings to their respective values,
+  and some effects may look like they've been "clipped" out.
+
+  <center>
+  @image html filter_padding.png
+  </center>
+
   @since 1.10
  */