><span class="hljs-keyword">function</span> <span class="hljs-params">(d)</span> {</span>
              x1 = d3.event.sourceEvent.pageX;
            })
            .on(<span class="hljs-string">'drag'</span>, <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-params">(d)</span> {</span>
              <span class="hljs-keyword">var</span> x2 = d3.event.sourceEvent.pageX,
                  newLineWidth = model.get(<span class="hljs-string">'lineWidth'</span>) + x2 - x1;
 