[LNT] Add support for logarithmic scale.

[marxin]

Summary

This adds support for logarithmic scale for plots.

[marxin]

May I please remind a patch review.

[MatzeB]

I think this is fine, but maybe wait a week or so before comitting in case @cmatthews has more comments.

[cmatthews]

Looks good. Thanks!

lnt/trunk/lnt/server/ui/templates/v4_graph.html

 {% block onload %}init_page(){% endblock %}
 
 {% block javascript %}
 var g = {};
 var test_suite_name = "{{ request.view_args.testsuite_name }}";
 var db_name = "{{ request.view_args.get('db_name','') }}";
 var graph_plots = {{graph_plots|tojson|safe}};
 var baseline_plots = {{baseline_plots|tojson|safe}};
+var options = {{options|tojson|safe}};
 prefix = "{{request.base_url}}";
 
+transform_fn = function (v) { return v; }
+inverse_transform_fn = function (v) { return v; }
+
+if (options.logarithmic_scale) {
+    transform_fn = function(v) {
+      if (v < 0)
+        return -Math.log10(-v);
+      else if (v > 0)
+        return Math.log10(v);
+      else
+        return 0;
+    }
+    inverse_transform_fn = function(v) {
+      if (v < 0)
+        return -Math.pow(10, -v);
+      else if (v > 0)
+        return Math.pow(10, v);
+      else
+        return 0;
+    }
+}
+
 function init_graph() {
   // Set up the primary graph.
   var graph = $("#graph");
   var graph_options = {
       series : {
         lines : {
           lineWidth : 1 },
         shadowSize : 0
         },
       highlight : {
 {% if revision_range is not none %}
         range: {{revision_range|tojson|safe}}
 {% else %}
         enabled: false
 {% endif %}
       },
       zoom : { interactive : false },
       pan : { interactive : true,
               frameRate: 60 },
       grid : {
         hoverable : true,
-        clickable: true }
+        clickable: true },
+        yaxis: {
+          transform: transform_fn,
+          inverseTransform: inverse_transform_fn }
       };
 
   // Add baseline lines
   graph_options['grid']['markings'] = baseline_plots;
   var tmp_plots = update_graphplots(graph_plots);
   var main_plot = $.plot(graph, tmp_plots, graph_options);
 
   // Add tooltips.
<td>
                      {{ 'checked="checked"' if options.show_moving_average else ""}}/></td>
               </tr>
               <tr>
                 <td>Show Moving Median</td>
                 <td><input type="checkbox" name="show_moving_median" value="yes"
                      {{ 'checked="checked"' if options.show_moving_median else ""}}/></td>
               </tr>
               <tr>
+                <td>Show Logarithmic Scale</td>
+                <td><input type="checkbox" name="logarithmic_scale" value="yes"
+                     {{ 'checked="checked"' if options.logarithmic_scale else ""}}/></td>
+              </tr>
+              <tr>
                 <td>Moving Average/Median Window Size</td>
               </tr>
               {# Split this into a new row to avoid making the dialog wider. #}
               <tr>
                 <td><input type="text" name="moving_window_size"
                      value="{{ options.moving_window_size }}"/></td>
               </tr>
               <tr>

lnt/trunk/lnt/server/ui/views.py

def v4_graph():
     options['show_moving_average'] = moving_average = bool(
         request.args.get('show_moving_average'))
     options['show_moving_median'] = moving_median = bool(
         request.args.get('show_moving_median'))
     options['moving_window_size'] = moving_window_size = int(
         request.args.get('moving_window_size', 10))
     options['hide_highlight'] = bool(
         request.args.get('hide_highlight'))
+    options['logarithmic_scale'] = bool(
+        request.args.get('logarithmic_scale'))
+
     show_highlight = not options['hide_highlight']
 
     # Load the graph parameters.
     graph_parameters = []
     for name, value in request.args.items():
         # Plots to graph are passed as::
         #
         #  plot.<unused>=<machine id>.<test id>.<field index>