Documented the anti-alias feature. Fixes issue weewx#6.

Author: tkeffer

docs/changes.txt

@@ -31,8 +31,11 @@ Fixed reference to index.html.tmpl in the xstats example.
 Changed algorithm for calculating ET to something more appropriate for
 hourly values (former algorithm assumed daily values). Fixes issue #160.
 
-Fixed bug that was introduced in v3.6.0, which prevented wee_reports for working
-at anything other than the current time.
+Fixed bug that was introduced in v3.6.0, which prevented wee_reports from working
+for anything other than the current time.
+
+Documented the experimental anti-alias feature, which has been in weewx
+since v3.1.0. Fixes issue #6.
 
 
 3.6.2 11/08/2016

docs/customizing.htm

@@ -3887,11 +3887,25 @@ <h3>Overall options</h3>
             <span class='code'>0xa0a0a0</span></p>
 
         <div class="image image-right" style="clear:right">
-            <img src="images/weektempdew.png" alt="Example of day/night bands"/>
+            <div class="image" >
+                <img src="images/antialias.gif" alt="Effect of anti_alias option"/>
 
-            <div class="image_caption">Example of day/night bands in a one
-            week image</div>
+                <div class="image_caption">A GIF showing the same image with
+                <span class="code">anti_alias=1</span>, <span class="code">2</span>, and
+                <span class="code">4</span>.</div>
+            </div>
+            <div class="image">
+                <img src="images/weektempdew.png" alt="Example of day/night bands"/>
+
+                <div class="image_caption">Example of day/night bands in a one
+                    week image</div>
+            </div>
         </div>
+        <p class="config_option">anti_alias</p>
+
+        <p>Setting to 2 or more might give a sharper image, with fewer jagged edges. Experimentation is
+            in order. Default is <span class="code">1</span>.</p>
+
         <p class="config_option">show_daynight</p>
 
         <p>

docs/images/antialias.gif

@@ -295,6 +295,9 @@
     chart_background_color = 0xd8d8d8
     chart_gridline_color = 0xa0a0a0
 
+    # Setting to 2 or more might give a sharper image with fewer jagged edges.
+    anti_alias = 1
+    
     top_label_font_path = /usr/share/fonts/truetype/freefont/FreeMonoBold.ttf
     top_label_font_size = 10