Question

我有一个Django应用程序，它根据通过UI进行的选择在浏览器上绘制图像。每当UI发生变化时，都会调用JavaScript函数，并创建一个调用django视图。

每当我从浏览器更改UI时，一个新的Image由views.py中的函数创建，并作为HTTPResponse返回给Javascript，最终在浏览器上绘制图像。

这里的问题是旧图像没有被删除，并且在浏览器上绘制了一个新图像，如下图所示

这是第一次加载页面的时间

当UI更改为PCA时

当我再次选择Kmeans时，它仍然显示上一个图表

我已经检查过所有计算都是在views.py中进行的，并且值会返回给模板。

views.py
class PlotTool(View):

@staticmethod
def kmeansPlot(request):
    [X,labels] = cluster_kmeans(request.GET.get('value'))
    color = ["g", "r", 'purple','olive','teal','orchid','darkorange']
    size = [90] * len(X)
    for i in xrange(len(X)):
        plt.scatter(X[i][0], X[i][1], c=color[labels[i]],s=size[i])

    #To Show Centroids on Plot
    plt.title('Kmeans')
    plt.grid(True)

    # Store image in a string buffer
    buffer = StringIO.StringIO()
    canvas = pylab.get_current_fig_manager().canvas
    canvas.draw()
    pilImage = PIL.Image.fromstring("RGB", canvas.get_width_height(), canvas.tostring_rgb())
    pilImage.save(buffer, "PNG")
    response = HttpResponse(buffer.getvalue(), content_type="image/png")
    return response


    @staticmethod
def PCAPlot(request):

    score,coeff,labels = pcaAnalysis()
    xs = score[:,0]
    ys = score[:,1]
    n=coeff.shape[0]
    scalex = 1.0/(xs.max()- xs.min())
    scaley = 1.0/(ys.max()- ys.min())
    plt.scatter(xs*scalex,ys*scaley)
    for i in range(n):
        plt.arrow(0, 0, coeff[i,0], coeff[i,1],color='r',alpha=0.5)
        if labels is None:
            plt.text(coeff[i,0]* 1.15, coeff[i,1] * 1.15, "Var"+str(i+1), color='g', ha='center', va='center')
        else:
            plt.text(coeff[i,0]* 1.15, coeff[i,1] * 1.15, labels[i], color='g', ha='center', va='center')

    plt.title('PCA')
    plt.xlim(-1,1)
    plt.ylim(-1,1)
    plt.xlabel("PC{}".format(1))
    plt.ylabel("PC{}".format(2))
    plt.grid()

    # Store image in a string buffer
    buffer = StringIO.StringIO()
    canvas = pylab.get_current_fig_manager().canvas
    canvas.draw()
    pilImage = PIL.Image.fromstring("RGB", canvas.get_width_height(), canvas.tostring_rgb())
    pilImage.save(buffer, "PNG")
    response = HttpResponse(buffer.getvalue(), content_type="image/png")
    return response

Python 2.7.10，Django 1.9 感谢任何帮助......谢谢

编辑：完整的Java脚本代码

＆＃13;

<body>
<div class="container">
 <div class="col-left">
<form action='#' method="get">
    <div>
    <label>No of Cluster</label>
    </div>

    <input id="slider1" type="range" class="myinput" value="3" min="2" max="10" step="1" onchange="callFun(dropdown1.value,this.value)" />
    <div class="count"><span>2</span><span>3</span><span>4</span><span>5</span><span>6</span><span>7</span><span>8</span><span>9</span><span style="border:none">10</span></div>
</form>
 </div>
  <div class="col-right">
    <label>Select Clustering Method</label>

<select name="test" id="dropdown1" onchange="callFun(this.value,slider1.value)">
  <option value="Kmeans Clustering" selected>Kmeans Clustering</option>
  <option value="Birch Clustering">Birch Clustering</option>
    <option value="PCA Plot">PCA Plot</option>
</select>

 </div>

<div style="width:100%; float:left;margin-top:30px;">
<img id="im" src='{% url "kmeans_graph" %}' align="left" height="400" width="400" >

<p id="demo">3</p>
</div>
    </div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/fetch/1.0.0/fetch.min.js"></script>

<script>
        function callFun(value1,value2) {
            if (value1 == 'Kmeans Clustering'){
               var img_src = '{% url "kmeans_graph" %}'
               document.getElementById("im").setAttribute("src",img_src + '?value=' + value2);
               document.getElementById("demo").innerHTML =value2
            }

            else if(value1 == 'Birch Clustering'){
                var img_src = '{% url "birch_graph" %}'
                document.getElementById("im").setAttribute("src",img_src + '?value=' + value2);
                document.getElementById("demo").innerHTML =value2
            }

            else{
                var img_src = '{% url "pca_graph" %}'
                document.getElementById("im").setAttribute("src",img_src + '?value=' + Math.random());
                document.getElementById("demo").innerHTML ='pca_graph'
            }
        }
    </script>


</body>
</html>

＆＃13;

Answer 1

得到答案......

在views.py中

pylab.get_current_fig_manager().canvas

在上面的代码fig = Figure() ax = fig.add_subplot(111) #change all plt instances with ax canvas=FigureCanvas(fig) response = HttpResponse(content_type='image/png') canvas.print_png(response)中获取当前的图形管理器，它每次都是相同的，这就是为什么它正在绘制旧图像而不是创建新图像。所以我把代码更改为

package.json

这对我有用

django并没有取代旧形象

1 个答案: