Improve readability

Added additional comments to improve readability of the genre graph
related code.

api/utils.py

@@ -186,13 +186,11 @@ def add_artist_genres(headers, artist_objs):
 
 #  get_artists_in_genre {{{ # 
 
-def get_artists_in_genre(user, genre, max_songs):
+def get_artists_in_genre(user, genre):
     """Return count of artists in genre.
 
     :user: User object to return data for.
     :genre: genre to count artists for. (string)
-    :max_songs: max total songs to include to prevent overflow due to having
-    multiple artists on each track.
 
     :returns: dict of artists in the genre along with the number of songs they
     have. 
@@ -204,19 +202,10 @@ def get_artists_in_genre(user, genre, max_songs):
     total_artist_counts = tracks_in_genre.aggregate(counts=Count('artists'))['counts']
 
     processed_artist_counts = {}
-    # songs_added = 0
     for artist in user_artists:
-        # hacky way to not have total count overflow due to there being multiple
-        # artists on a track
-        # if songs_added + artist.num_songs <= max_songs:
-        #     processed_artist_counts[artist.name] = artist.num_songs
-        #     songs_added += artist.num_songs
         processed_artist_counts[artist.name] = round(artist.track_set
                                                      .filter(genre=genre_obj, users=user)
                                                      .count() * track_count / total_artist_counts, 2)
-    #  processed_artist_counts = [{'name': artist.name, 'num_songs': artist.num_songs} for artist in artist_counts]
-    #  processed_artist_counts = {artist.name: artist.num_songs for artist in artist_counts}
-    #  pprint.pprint(processed_artist_counts)
     return processed_artist_counts
 
 #  }}} get_artists_in_genre # 

api/views.py

@@ -176,10 +176,30 @@ def get_genre_data(request, user_secret):
     genre_counts = (Track.objects.filter(users__exact=user)
                     .values('genre')
                     .order_by('genre')
+                    # annotates each genre and not each Track, due to the earlier values() call
                     .annotate(num_songs=Count('genre'))
                     )
+    # genre_counts is a QuerySet with the format
+    # [{'genre': 'classical', 'num_songs': 100}, {'genre': 'pop', 'num_songs': 50}...]
     for genre_dict in genre_counts:
-        genre_dict['artists'] = get_artists_in_genre(user, genre_dict['genre'], genre_dict['num_songs'])
+        genre_dict['artists'] = get_artists_in_genre(user, genre_dict['genre'])
+    '''
+    Now genre_counts has the format
+    [
+    {'genre': 'classical',
+     'num_songs': 100,
+     'artists': {
+                'Helene Grimaud': 40.5,
+                'Beethoven': 31.2,
+                'Mozart': 22...
+                }
+    },
+    {'genre': 'pop',
+     'num_songs': 150,
+     'artists': {...}
+    },...
+    ]
+    '''
     print("*** Genre Breakdown ***")
     pprint.pprint(list(genre_counts))
     return JsonResponse(data=list(genre_counts), safe=False) 

graphs/static/graphs/scripts/genre_graph.js

@@ -22,9 +22,9 @@ function create_genre_graph(data) {
     x.domain(data.map(function(d) {
         return d.genre;
     }));
-    //y.domain([0, d3.max(data, function(d) { return d.num_songs; }) * 1.25]).nice();
+    // y.domain([0, d3.max(data, function(d) { return d.num_songs; }) * 1.25]).nice();
     y.domain([0, d3.max(data, function(d) {
-        return d.num_songs;
+        return d.num_songs; // returns the maximum number of songs in the genre
     })]).nice();
 	
 	// }}} domains  //
@@ -34,7 +34,7 @@ function create_genre_graph(data) {
     let max_artists = d3.max(data, function(d) {
         return Object.keys(d.artists).length;
     });
-    let z = d3.scaleOrdinal().range(randomColor({
+    let colorScale = d3.scaleOrdinal().range(randomColor({
         count: max_artists,
         luminosity: 'light',
     }));
@@ -47,10 +47,9 @@ function create_genre_graph(data) {
         
         let keys = Object.keys(genre_dict.artists);
         let stack = d3.stack()
-            //.order(d3.stackOrderAscending)
             .order(d3.stackOrderDescending)
             .keys(keys)([genre_dict.artists])
-            //unpack the column
+            // unpack the column
             .map((d, i) => {
                 return {
                     key: keys[i],
@@ -72,8 +71,9 @@ function create_genre_graph(data) {
             })
             .attr("height", d => y(d.data[0]) - y(d.data[1]))
             .attr("width", x.bandwidth())
-            .attr('fill', (d, i) => z(i))
-            .append('title').text(d => d.key + ': ' + (d.data[1] - d.data[0]));
+            .attr('fill', (d, i) => colorScale(i))
+            // keep 3 significant figures in the song count label
+            .append('title').text(d => d.key + ': ' + (d.data[1] - d.data[0]).toPrecision(3));
         
         // }}} add bars //
 
@@ -108,7 +108,7 @@ function create_genre_graph(data) {
 }
 
 // wrap text {{{ //
-
+// wrapping long labels
 // https://gist.github.com/guypursey/f47d8cd11a8ff24854305505dbbd8c07#file-index-html
 function wrap(text, width) {
     text.each(function() {
@@ -122,13 +122,13 @@ function wrap(text, width) {
             dy = parseFloat(text.attr("dy")),
             tspan = text.text(null).append("tspan").attr("x", 0).attr("y", y).attr("dy", dy + "em")
         while (word = words.pop()) {
-            line.push(word)
-            tspan.text(line.join(" "))
+            line.push(word);
+            tspan.text(line.join(" "));
             if (tspan.node().getComputedTextLength() > width) {
-                line.pop()
-                tspan.text(line.join(" "))
-                line = [word]
-                tspan = text.append("tspan").attr("x", 0).attr("y", y).attr("dy", `${++lineNumber * lineHeight + dy}em`).text(word)
+                line.pop();
+                tspan.text(line.join(" "));
+                line = [word];
+                tspan = text.append("tspan").attr("x", 0).attr("y", y).attr("dy", `${++lineNumber * lineHeight + dy}em`).text(word);
             }
         }
     })

graphs/templates/graphs/genre_graph.html

@@ -13,7 +13,7 @@
 	<title>Test DB Page</title>
 	<meta name="description" content="">
 	<meta name="viewport" content="width=device-width, initial-scale=1">
-    <link rel="stylesheet" href="{% static 'css/dark_bg.css' %}">
+{#    <link rel="stylesheet" href="{% static 'css/dark_bg.css' %}">#}
 </head>
 
 <!-- }}} header -->
@@ -33,7 +33,8 @@
         g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");
     let x = d3.scaleBand()
         .rangeRound([0, width])
-        .paddingInner(0.05)
+        .paddingInner(0.1)
+        .paddingOuter(0.7)
         .align(0.1);
     let y = d3.scaleLinear()
         .rangeRound([height, 0]);