Backport PR #19131: Fix WebAgg initialization

tacaswell · QuLogic · commit df7f639ad447 · 2020-12-22T16:19:45.000-05:00
diff --git a/lib/matplotlib/backends/web_backend/js/mpl.js b/lib/matplotlib/backends/web_backend/js/mpl.js
@@ -157,9 +157,6 @@ mpl.figure.prototype._init_canvas = function () {
         1;
 
     this.ratio = (window.devicePixelRatio || 1) / backingStore;
-    if (this.ratio !== 1) {
-        fig.send_message('set_dpi_ratio', { dpi_ratio: this.ratio });
-    }
 
     var rubberband_canvas = (this.rubberband_canvas = document.createElement(
         'canvas'
@@ -227,7 +224,7 @@ mpl.figure.prototype._init_canvas = function () {
             // And update the size in Python. We ignore the initial 0/0 size
             // that occurs as the element is placed into the DOM, which should
             // otherwise not happen due to the minimum size styling.
-            if (width != 0 && height != 0) {
+            if (fig.ws.readyState == 1 && width != 0 && height != 0) {
                 fig.request_resize(width, height);
             }
         }
