Made sure that histogram graph doesn't show up for modules without scores.…

Made sure that histogram graph doesn't show up for modules without scores. Modified look of histogram graph.

djangoapps/courseware/module_render.py

@@ -103,8 +103,9 @@ def grade_histogram(module_id):
     cursor.execute("select courseware_studentmodule.grade,COUNT(courseware_studentmodule.student_id) from courseware_studentmodule where courseware_studentmodule.module_id=%s group by courseware_studentmodule.grade", [module_id])
 
     grades = list(cursor.fetchall())
-    print grades
     grades.sort(key=lambda x:x[0]) # Probably not necessary
+    if (len(grades) == 1 and grades[0][0] == None):
+        return []
     return grades
 
 def render_x_module(user, request, xml_module, module_object_preload):
@@ -147,9 +148,13 @@ def render_x_module(user, request, xml_module, module_object_preload):
     init_js = instance.get_init_js()
     destory_js = instance.get_destroy_js()
     if user.is_staff:
+        histogram = grade_histogram(module_id)
+        render_histogram = len(histogram) > 0
         content=content+render_to_string("staff_problem_info.html", {'xml':etree.tostring(xml_module), 
-                                                                     'module_id' : module_id})
-        init_js = init_js+render_to_string("staff_problem_histogram.js", {'histogram' : grade_histogram(module_id),
+                                                                     'module_id' : module_id,
+                                                                     'render_histogram' : render_histogram})
+        if render_histogram:
+            init_js = init_js+render_to_string("staff_problem_histogram.js", {'histogram' : histogram,
                                                                               'module_id' : module_id})
         
     content = {'content':content, 

templates/staff_problem_histogram.js

@@ -9,6 +9,7 @@ xticks = []
 yticks = []
 maxx = 1
 maxy = 1.5
+#Here we change the y-axis (count) to be logorithmic. We also define better ticks
 for score, count in histogram:
     score = score or 0 #Sometimes score is None. This fixes that
         
@@ -30,9 +31,9 @@ $.plot($("#histogram_${module_id}"), [{
             align: 'center',
             lineWidth: 0, 
             fill: 1.0 },
-    color: "#600101",
+    color: "#b72121",
   }],
   {
-    xaxis: {min: -1, max: ${maxx}, ticks: ${ json.dumps(xticks) }},
+    xaxis: {min: -1, max: ${maxx}, ticks: ${ json.dumps(xticks) }, tickLength: 0},
     yaxis: {min: 0.0, max: ${maxy}, ticks: ${ json.dumps(yticks) }, labelWidth: 50},
   });

templates/staff_problem_info.html

 <div class="staff_info">
 ${xml | h}
 </div>
-<div id="histogram_${module_id}" style="width:200px;height:150px"></div>
+%if render_histogram:
+  <div id="histogram_${module_id}" style="width:200px;height:150px"></div>
+%endif