Fix - properly adjust size of stats box

Depending from histogram type and showing fit parameters,
different algorithm is used to adjust size of the stats box.
Make it maximally the same as in ROOT

Author: linev

modules/hist/TPavePainter.mjs

@@ -196,9 +196,22 @@ class TPavePainter extends ObjectPainter {
                // we take statistic from main painter
                if (main.fillStatistic(this, dostat, dofit)) {
                   // adjust the size of the stats box with the number of lines
-                  const nlines = pt.fLines?.arr.length || 0;
-                  if ((nlines > 0) && !this.moved_interactive && ((gStyle.fStatFontSize <= 0) || (gStyle.fStatFont % 10 === 3)))
-                     pt.fY1NDC = Math.max(0.02, pt.fY2NDC - ((nlines < 8) ? nlines * 0.25 * gStyle.fStatH : nlines * 0.025));
+                  let nlines = pt.fLines?.arr.length || 0;
+                  if ((nlines > 0) && !this.moved_interactive) {
+                     // in ROOT TH2 and TH3 always add full statsh for fit parameters
+                     const extrah = this._has_fit && (this._fit_dim > 1) ? gStyle.fStatH : 0;
+                     // but fit parameters not used in full size calculations
+                     if (extrah) nlines -= this._fit_cnt;
+                     let stath = gStyle.fStatH, statw = gStyle.fStatW;
+                     if (this._has_fit)
+                        statw = 1.8 * gStyle.fStatW;
+                     if ((gStyle.fStatFontSize <= 0) || (gStyle.fStatFont % 10 === 3))
+                        stath = nlines * 0.25 * gStyle.fStatH;
+                     else if (gStyle.fStatFontSize < 1)
+                        stath = nlines * gStyle.fStatFontSize;
+                     pt.fX1NDC = Math.max(0.02, pt.fX2NDC - statw);
+                     pt.fY1NDC = Math.max(0.02, pt.fY2NDC - stath - extrah);
+                  }
                }
             }
          }
@@ -1174,17 +1187,27 @@ class TPavePainter extends ObjectPainter {
 
    /** @summary Fill function parameters */
    fillFunctionStat(f1, dofit, ndim = 1) {
+      this._has_fit = false;
+
       if (!dofit || !f1) return false;
 
+      this._has_fit = true;
+      this._fit_dim = ndim;
+      this._fit_cnt = 0;
+
       const print_fval = (ndim === 1) ? dofit % 10 : 1,
             print_ferrors = (ndim === 1) ? Math.floor(dofit/10) % 10 : 1,
             print_fchi2 = (ndim === 1) ? Math.floor(dofit/100) % 10 : 1,
             print_fprob = (ndim === 1) ? Math.floor(dofit/1000) % 10 : 0;
 
-      if (print_fchi2)
+      if (print_fchi2) {
          this.addText('#chi^{2} / ndf = ' + this.format(f1.fChisquare, 'fit') + ' / ' + f1.fNDF);
-      if (print_fprob)
+         this._fit_cnt++;
+      }
+      if (print_fprob) {
          this.addText('Prob = ' + this.format(Prob(f1.fChisquare, f1.fNDF)));
+         this._fit_cnt++;
+      }
       if (print_fval) {
          for (let n = 0; n < f1.GetNumPars(); ++n) {
             const parname = f1.GetParName(n);
@@ -1201,9 +1224,11 @@ class TPavePainter extends ObjectPainter {
                this.addText(`${parname} = ${parvalue} #pm ${parerr}`);
             else
                this.addText(`${parname} = ${parvalue}`);
+            this._fit_cnt++;
          }
       }
 
+
       return true;
    }