Use private member for frame painter

Author: linev

modules/gpad/RFramePainter.mjs

@@ -626,9 +626,7 @@ class RFramePainter extends RObjectPainter {
       delete this._click_handler;
       delete this._dblclick_handler;
 
-      const pp = this.getPadPainter();
-      if (pp?.frame_painter_ref === this)
-         delete pp.frame_painter_ref;
+      this.getPadPainter()?.setFramePainter(this, false);
 
       super.cleanup();
    }
@@ -637,7 +635,7 @@ class RFramePainter extends RObjectPainter {
      * @private */
    redraw() {
       const pp = this.getPadPainter();
-      if (pp) pp.frame_painter_ref = this;
+      pp?.setFramePainter(this, true);
 
       // first update all attributes from objects
       this.updateAttributes();

modules/gpad/RPadPainter.mjs

@@ -25,6 +25,7 @@ class RPadPainter extends RObjectPainter {
    #pad_height; // pad height
    #doing_draw; // drawing handles
    #custom_palette; // custom palette
+   #frame_painter_ref; // frame painter
 
    /** @summary constructor */
    constructor(dom, pad, iscan) {
@@ -109,7 +110,7 @@ class RPadPainter extends RObjectPainter {
       if (cp) delete cp.pads_cache;
 
       delete this.main_painter_ref;
-      delete this.frame_painter_ref;
+      this.#frame_painter_ref = undefined;
       this.#pad_x = this.#pad_y = this.#pad_width = this.#pad_height = undefined;
       this.#doing_draw = undefined;
       delete this._dfltRFont;
@@ -128,7 +129,16 @@ class RPadPainter extends RObjectPainter {
 
    /** @summary Returns frame painter inside the pad
     * @private */
-   getFramePainter() { return this.frame_painter_ref; }
+   getFramePainter() { return this.#frame_painter_ref; }
+
+   /** @summary Assign actual frame painter
+     * @private */
+   setFramePainter(fp, on) {
+      if (on)
+         this.#frame_painter_ref = fp;
+      else if (this.#frame_painter_ref === fp)
+         this.#frame_painter_ref = undefined;
+   }
 
    /** @summary get pad width */
    getPadWidth() { return this.#pad_width || 0; }

modules/gpad/TFramePainter.mjs

@@ -2481,17 +2481,15 @@ class TFramePainter extends ObjectPainter {
       delete this._dblclick_handler;
       delete this.enabledKeys;
 
-      const pp = this.getPadPainter();
-      if (pp?.frame_painter_ref === this)
-         delete pp.frame_painter_ref;
+      this.getPadPainter()?.setFramePainter(this, false);
 
       super.cleanup();
    }
 
    /** @summary Redraw TFrame */
    redraw(/* reason */) {
       const pp = this.getPadPainter();
-      if (pp) pp.frame_painter_ref = this; // keep direct reference to the frame painter
+      pp?.setFramePainter(this, true);
 
       // first update all attributes from objects
       this.updateAttributes();

modules/gpad/TPadPainter.mjs

@@ -215,6 +215,7 @@ class TPadPainter extends ObjectPainter {
    #custom_colors;  // custom colors
    #custom_palette_indexes; // custom palette indexes
    #custom_palette_colors; // custom palette colors
+   #frame_painter_ref; // frame painter
 
    /** @summary constructor
      * @param {object|string} dom - DOM element for drawing or element id
@@ -295,7 +296,7 @@ class TPadPainter extends ObjectPainter {
       }
 
       delete this.main_painter_ref;
-      delete this.frame_painter_ref;
+      this.#frame_painter_ref = undefined;
       const cp = this.iscan || !this.has_canvas ? this : this.getCanvPainter();
       if (cp) delete cp.pads_cache;
       this.#pad_x = this.#pad_y = this.#pad_width = this.#pad_height = undefined;
@@ -317,7 +318,16 @@ class TPadPainter extends ObjectPainter {
 
    /** @summary Returns frame painter inside the pad
      * @private */
-   getFramePainter() { return this.frame_painter_ref; }
+   getFramePainter() { return this.#frame_painter_ref; }
+
+   /** @summary Assign actual frame painter
+     * @private */
+   setFramePainter(fp, on) {
+      if (on)
+         this.#frame_painter_ref = fp;
+      else if (this.#frame_painter_ref === fp)
+         this.#frame_painter_ref = undefined;
+   }
 
    /** @summary get pad width */
    getPadWidth() { return this.#pad_width || 0; }