Check if element is empty before drawing

Author: linev

scripts/JSRoot.core.js

@@ -105,7 +105,7 @@
 
    /** @summary JSROOT version date
      * @desc Release date in format day/month/year like "6/01/2021"*/
-   JSROOT.version_date = "7/01/2021";
+   JSROOT.version_date = "8/01/2021";
 
    /** @summary JSROOT version id and date
      * @desc Produced by concatenation of {@link JSROOT.version_id} and {@link JSROOT.version_date}

scripts/JSRoot.painter.js

@@ -2408,10 +2408,10 @@ JSROOT.define(['d3'], (d3) => {
    ObjectPainter.prototype.startTextDrawing = function(font_face, font_size, draw_g, max_font_size) {
 
       if (!draw_g) draw_g = this.draw_g;
+      if (!draw_g || draw_g.empty()) return;
 
-      let font = (font_size === 'font') ? font_face : new FontHandler(font_face, font_size);
-
-      let pp = this.getPadPainter();
+      let font = (font_size === 'font') ? font_face : new FontHandler(font_face, font_size),
+          pp = this.getPadPainter();
 
       draw_g.call(font.func);
 
@@ -2421,7 +2421,7 @@ JSROOT.define(['d3'], (d3) => {
             .property('text_factor', 0.)
             .property('max_text_width', 0) // keep maximal text width, use it later
             .property('max_font_size', max_font_size)
-            .property("_fast_drawing", pp && pp._fast_drawing);
+            .property("_fast_drawing", pp ? pp._fast_drawing : false);
 
       if (draw_g.property("_fast_drawing"))
          draw_g.property("_font_too_small", (max_font_size && (max_font_size < 5)) || (font.size < 4));