Provide experimental 'limit' draw option for geometry

One could use it to limit number of drawn values by 10000.
It is seems to be realistic number, which can be handled in the browser

Author: linev

scripts/JSRootGeoPainter.js

@@ -706,6 +706,7 @@
    JSROOT.TGeoPainter.prototype.drawNode = function(scene, toplevel, node, visible) {
       var container = toplevel;
       var volume = node['fVolume'];
+      if (visible==0) return; // cut all volumes below 0 level
 
       var translation_matrix = [0, 0, 0];
       var rotation_matrix = null;//[1, 0, 0, 0, 1, 0, 0, 0, 1];
@@ -961,20 +962,35 @@
 
       var dom = this.select_main().node();
 
-      if (opt == 'count') {
+      var maxlvl = opt=="all" ? 9999 : -1;
+
+      if ((opt == 'count') || (opt == 'limit')) {
          var arr = [];
          for (var lvl=0;lvl<100;++lvl) arr.push(0);
 
          var cnt = this.CountVolumes(this._geometry, 0, arr);
 
-         var res = 'Total number: ' + cnt + '<br/>';
-         for (var lvl=0;lvl<arr.length;++lvl) {
-            if (arr[lvl] !== 0)
-               res += ('  lvl' + lvl + ': ' + arr[lvl] + '<br/>');
+         if (opt == 'count') {
+            var res = 'Total number: ' + cnt + '<br/>';
+            for (var lvl=0;lvl<arr.length;++lvl) {
+               if (arr[lvl] !== 0)
+                  res += ('  lvl' + lvl + ': ' + arr[lvl] + '<br/>');
+            }
+
+            dom.innerHTML = res;
+            return this.DrawingReady();
+         }
+
+         var sum = 0;
+         for (var lvl=1;lvl<arr.length;++lvl) {
+            sum += arr[lvl];
+            if (sum > 10000) {
+               maxlvl = lvl - 1;
+               console.log('set level on ' + maxlvl);
+               break;
+            }
          }
 
-         dom.innerHTML = res;
-         return this.DrawingReady();
       }
 
       // three.js 3D drawing
@@ -1033,7 +1049,7 @@
                   visible: false, transparent: true, opacity: 0.0 } ) );
          toplevel.add(cube);
 
-         this.drawNode(this._scene, cube, { _typename:"TGeoNode", fVolume:this._geometry, fName:"TopLevel" }, opt=="all" ? 9999 : 0);
+         this.drawNode(this._scene, cube, { _typename:"TGeoNode", fVolume:this._geometry, fName:"TopLevel" }, maxlvl);
 
          top.computeBoundingBox();
          var overall_size = 3 * Math.max( Math.max(Math.abs(top.boundingBox.max.x), Math.abs(top.boundingBox.max.y)),
@@ -1419,7 +1435,7 @@
       return true;
    }
 
-   JSROOT.addDrawFunc({ name: "TGeoVolumeAssembly", icon: 'img_geoassembly', func: JSROOT.Painter.drawGeometry, expand: "JSROOT.expandGeoVolume", painter_kind : "base", opt : "all;count;" });
+   JSROOT.addDrawFunc({ name: "TGeoVolumeAssembly", icon: 'img_geoassembly', func: JSROOT.Painter.drawGeometry, expand: "JSROOT.expandGeoVolume", painter_kind : "base", opt : "all;count;limit;" });
 
 
    return JSROOT.Painter;

scripts/JSRootPainter.js

@@ -8314,8 +8314,8 @@
    JSROOT.addDrawFunc({ name: "TLine", icon: 'img_graph', prereq: "more2d", func: "JSROOT.Painter.drawLine" });
    JSROOT.addDrawFunc({ name: "TArrow", icon: 'img_graph', prereq: "more2d", func: "JSROOT.Painter.drawArrow" });
    JSROOT.addDrawFunc({ name: "TLegend", icon: "img_pavelabel", prereq: "more2d", func: "JSROOT.Painter.drawLegend" });
-   JSROOT.addDrawFunc({ name: "TGeoVolume", icon: 'img_histo3d', prereq: "geom", func: "JSROOT.Painter.drawGeometry", expand: "JSROOT.expandGeoVolume", painter_kind : "base", opt:"all;count;" });
-   JSROOT.addDrawFunc({ name: "TEveGeoShapeExtract", icon: 'img_histo3d', prereq: "geom", func: "JSROOT.Painter.drawGeometry", painter_kind : "base", opt: ";count"  });
+   JSROOT.addDrawFunc({ name: "TGeoVolume", icon: 'img_histo3d', prereq: "geom", func: "JSROOT.Painter.drawGeometry", expand: "JSROOT.expandGeoVolume", painter_kind : "base", opt:"all;count;limit;" });
+   JSROOT.addDrawFunc({ name: "TEveGeoShapeExtract", icon: 'img_histo3d', prereq: "geom", func: "JSROOT.Painter.drawGeometry", painter_kind : "base", opt: ";count;limit"  });
    JSROOT.addDrawFunc({ name: "TGeoManager", icon: 'img_histo3d', prereq: "geom", expand: "JSROOT.expandGeoManagerHierarchy" });
    // these are not draw functions, but provide extra info about correspondent classes
    JSROOT.addDrawFunc({ name: "kind:Command", icon: "img_execute", execute: true });