add docs for layer level gamma

c.f. MapServer/MapServer#4763
MapServer · Sep 25, 2013 · 84aff95 · 84aff95
1 parent ceea5e6
commit 84aff95
Showing 1 changed file with 14 additions and 0 deletions.
diff --git a/en/mapfile/layer.txt b/en/mapfile/layer.txt
@@ -702,6 +702,20 @@ PROCESSING [string]
 
           PROCESSING "GETSHAPE_STYLE_ITEMS=all"
 
+    .. index::
+       triple: LAYER; PROCESSING; GAMMA
+
+    - **AGG renderer tweaking** - This directive can be used for setting
+      the linear gamma to be used when rendering polygon features. The 
+      default value of 0.75 (that can be overriden at the :ref:`outputformat`
+      level) can be set to a lower value to limit/remove the faint outlines
+      that appear between adjacent polygons. A value of 0.5 is usually good
+      enough.
+
+      .. code-block:: mapfile
+
+          PROCESSING "GAMMA=0.5"
+
     .. index::
        triple: LAYER; PROCESSING; raster options