Let configure alternative draw function

demo/node/hpainter.js

@@ -2,8 +2,8 @@
 // in batch display one just able to create images
 
 
-import { version, HierarchyPainter, draw } from 'jsroot';
-
+import { version, HierarchyPainter, draw, addDrawFunc } from 'jsroot';
+// import { writeFileSync } from 'fs';
 
 console.log(`JSROOT version ${version}`);
 
@@ -14,27 +14,34 @@ const hp = new HierarchyPainter('hpainter');
 hp.setDisplay('batch');
 
 // catch draw function calls
-hp.setDrawFunc((dom, obj, opt) => {
-   console.log(`trying to draw ${obj._typename}`);
-   return draw(dom, obj, opt);
+addDrawFunc({
+   name: '*',
+   func: (dom, obj, opt) => {
+      console.log(`Actual draw of ${obj._typename}`);
+      // if function return true no normal drawing will be performed
+      // do not try to call `draw` function from here !!!
+      // return true;
+   }
 });
 
 await hp.openRootFile('https://root.cern/js/files/hsimple.root');
 
 // display of TH2 histogram
+console.log('Invoke histogram drawing');
 await hp.display('hpxpy');
 
 await hp.expandItem('ntuple');
 
 // invoking TTree::Draw
+console.log('Invoke TBranch drawing');
 await hp.display('ntuple/pz');
 
-
 // should be BatchDisplay
 const disp = hp.getDisplay();
 
 for (let id = 0; id < disp.numFrames(); ++id) {
    const svg = await disp.makeSVG(id);
+
    console.log(`Frame ${id} create svg size ${svg.length}`);
 
    // one can save svg plain file

modules/draw.mjs

@@ -130,14 +130,14 @@ const drawFuncs = { lst: [
    { name: 'kind:Command', icon: 'img_execute', execute: true },
    { name: 'TFolder', icon: 'img_folder', icon2: 'img_folderopen', noinspect: true, get_expand: () => import_h().then(h => h.folderHierarchy) },
    { name: 'TTask', icon: 'img_task', get_expand: () => import_h().then(h => h.taskHierarchy), for_derived: true },
-   { name: clTTree, icon: 'img_tree', get_expand: () => import('./tree.mjs').then(h => h.treeHierarchy), draw: () => import_tree().then(h => h.drawTree), dflt: 'expand', opt: 'player;testio', shift: kInspect, pm: true },
+   { name: clTTree, icon: 'img_tree', get_expand: () => import('./tree.mjs').then(h => h.treeHierarchy), draw: () => import_tree().then(h => h.drawTree), dflt: 'expand', opt: 'player;testio', shift: kInspect, pm: true, transform: true },
    { name: 'TNtuple', sameas: clTTree },
    { name: 'TNtupleD', sameas: clTTree },
-   { name: clTBranchFunc, icon: 'img_leaf_method', draw: () => import_tree().then(h => h.drawTree), opt: ';dump', noinspect: true },
-   { name: /^TBranch/, icon: 'img_branch', draw: () => import_tree().then(h => h.drawTree), dflt: 'expand', opt: ';dump', ctrl: 'dump', shift: kInspect, ignore_online: true, always_draw: true },
-   { name: /^TLeaf/, icon: 'img_leaf', noexpand: true, draw: () => import_tree().then(h => h.drawTree), opt: ';dump', ctrl: 'dump', ignore_online: true, always_draw: true },
-   { name: 'ROOT::RNTuple', icon: 'img_tree', get_expand: () => import('./rntuple.mjs').then(h => h.tupleHierarchy), draw: () => import('./draw/RNTuple.mjs').then(h => h.drawRNTuple), dflt: 'expand', pm: true },
-   { name: 'ROOT::RNTupleField', icon: 'img_leaf', draw: () => import('./draw/RNTuple.mjs').then(h => h.drawRNTuple), opt: ';dump', ctrl: 'dump', shift: kInspect, ignore_online: true, always_draw: true },
+   { name: clTBranchFunc, icon: 'img_leaf_method', draw: () => import_tree().then(h => h.drawTree), opt: ';dump', noinspect: true, transform: true },
+   { name: /^TBranch/, icon: 'img_branch', draw: () => import_tree().then(h => h.drawTree), dflt: 'expand', opt: ';dump', ctrl: 'dump', shift: kInspect, ignore_online: true, always_draw: true, transform: true },
+   { name: /^TLeaf/, icon: 'img_leaf', noexpand: true, draw: () => import_tree().then(h => h.drawTree), opt: ';dump', ctrl: 'dump', ignore_online: true, always_draw: true, transform: true },
+   { name: 'ROOT::RNTuple', icon: 'img_tree', get_expand: () => import('./rntuple.mjs').then(h => h.tupleHierarchy), draw: () => import('./draw/RNTuple.mjs').then(h => h.drawRNTuple), dflt: 'expand', pm: true, transform: true },
+   { name: 'ROOT::RNTupleField', icon: 'img_leaf', draw: () => import('./draw/RNTuple.mjs').then(h => h.drawRNTuple), opt: ';dump', ctrl: 'dump', shift: kInspect, ignore_online: true, always_draw: true, transform: true },
    { name: clTList, icon: 'img_list', draw: () => import_h().then(h => h.drawList), get_expand: () => import_h().then(h => h.listHierarchy), dflt: 'expand' },
    { name: clTHashList, sameas: clTList },
    { name: clTObjArray, sameas: clTList },
@@ -169,19 +169,28 @@ const drawFuncs = { lst: [
 
 
 /** @summary Register draw function for the class
-  * @desc List of supported draw options could be provided, separated  with ';'
   * @param {object} args - arguments
-  * @param {string|regexp} args.name - class name or regexp pattern
+  * @param {string|regexp} args.name - class name or regexp pattern or '*'
   * @param {function} [args.func] - draw function
+  * @param {string} [args.sameas] - let behave same as specified class
   * @param {function} [args.draw] - async function to load draw function
   * @param {function} [args.class] - async function to load painter class with static draw function
   * @param {boolean} [args.direct] - if true, function is just Redraw() method of ObjectPainter
   * @param {string} [args.opt] - list of supported draw options (separated with semicolon) like 'col;scat;'
   * @param {string} [args.icon] - icon name shown for the class in hierarchy browser
   * @param {string} [args.draw_field] - draw only data member from object, like fHistogram
+  * @param {string} [args.noinspect] - disable inspect
+  * @param {string} [args.noexpand] - disable expand
+  * @param {string} [args.pm] - always show plus or minus sign even when no child items exists
+  * @desc List of supported draw options could be provided, separated  with ';'
+  * If args.name parameter is '*', function will be invoked before object drawing.
+  * If such function does not return value - normal drawing will be continued.
   * @protected */
 function addDrawFunc(args) {
-   drawFuncs.lst.push(args);
+   if (args?.name === '*')
+      internals._alt_draw = isFunc(args.func) ? args.func : null;
+   else
+      drawFuncs.lst.push(args);
    return args;
 }
 
@@ -392,6 +401,12 @@ async function draw(dom, obj, opt) {
    if (handle.draw_field && obj[handle.draw_field])
       return draw(dom, obj[handle.draw_field], opt || handle.draw_field_opt);
 
+   if (internals._alt_draw && !handle.transform) {
+      const v = internals._alt_draw(dom, obj, opt);
+      if (v)
+         return v;
+   }
+
    if (!canDrawHandle(handle)) {
       if (opt && (opt.indexOf('same') >= 0)) {
          const main_painter = getElementMainPainter(dom);

modules/draw/TTree.mjs

@@ -56,6 +56,12 @@ async function drawTreeDrawResult(dom, obj, opt) {
    if (!typ || !isStr(typ))
       return Promise.reject(Error('Object without type cannot be draw with TTree'));
 
+   if (internals._alt_draw) {
+      const v = internals._alt_draw(dom, obj, opt);
+      if (v)
+         return v;
+   }
+
    if (typ.indexOf(clTH1) === 0)
       return TH1Painter.draw(dom, obj, opt);
    if (typ.indexOf(clTH2) === 0)

modules/gui/HierarchyPainter.mjs

@@ -825,8 +825,6 @@ class HierarchyPainter extends BasePainter {
    #one_by_one;  // process drop items one by one
    #topname; // top item name
    #cached_draw_object; // cached object for first draw
-   #draw_func; // alternative draw function
-   #redraw_func; // alternative redraw function
 
    /** @summary Create painter
      * @param {string} name - symbolic name
@@ -857,23 +855,6 @@ class HierarchyPainter extends BasePainter {
       this.textcolor = settings.DarkMode ? '#eee' : '#111';
    }
 
-   /** @summary Set alternative draw/redraw functions
-    * @desc If only only draw function specified - it also will be used for re-drawing
-    * @protected */
-   setDrawFunc(_draw, _redraw) {
-      if (isFunc(_draw)) {
-         this.#draw_func = _draw;
-         this.#redraw_func = isFunc(_redraw) ? _redraw : _draw;
-      }
-   }
-
-   /** @summary Invoke configured draw or redraw function
-    * @protected */
-   async callDrawFunc(dom, obj, opt, doredraw) {
-      const func = doredraw ? (this.#redraw_func || redraw) : (this.#draw_func || draw);
-      return func(dom, obj, opt);
-   }
-
    /** @summary Cleanup hierarchy painter
      * @desc clear drawing and browser */
    cleanup() {
@@ -2313,7 +2294,7 @@ class HierarchyPainter extends BasePainter {
                drawopt = handle.dflt;
 
             if (dom)
-               return this.callDrawFunc(dom, obj, drawopt, updating).then(p => complete(p)).catch(err => complete(null, err));
+               return (updating ? redraw : draw)(dom, obj, drawopt).then(p => complete(p)).catch(err => complete(null, err));
 
             let did_activate = false;
             const arr = [];
@@ -2357,7 +2338,7 @@ class HierarchyPainter extends BasePainter {
             cleanup(frame);
             mdi.activateFrame(frame);
 
-            return this.callDrawFunc(frame, obj, drawopt)
+            return draw(frame, obj, drawopt)
                        .then(p => complete(p))
                        .catch(err => complete(null, err));
          });
@@ -2465,7 +2446,7 @@ class HierarchyPainter extends BasePainter {
          if (isFunc(dom?.addPadButtons))
             dom.addPadButtons();
 
-         return this.callDrawFunc(dom, res.obj, opt).then(p => drop_complete(p, mp === p));
+         return draw(dom, res.obj, opt).then(p => drop_complete(p, mp === p));
       });
    }