Include first value when computing automatic TTree::Draw histogram range

.github/workflows/jsroot-ci.yml

@@ -68,6 +68,7 @@ jobs:
           node demo/node/rntuple_buffer_test.js
           node demo/node/rntuple_test.js demo/node/rntuple_test.root
           node demo/node/tree_int64_test.js demo/node/tree_int64_test.root
+          node demo/node/tree_draw_range.js demo/node/rntuple_test.root
           node demo/node/rntuple_test32.js demo/node/rntuple_test32.root demo/node/rntuple_test32.json
 
   tests_ubuntu:
@@ -187,6 +188,7 @@ jobs:
           node demo/node/rntuple_buffer_test.js
           node demo/node/rntuple_test.js demo/node/rntuple_test.root
           node demo/node/tree_int64_test.js demo/node/tree_int64_test.root
+          node demo/node/tree_draw_range.js demo/node/rntuple_test.root
           node demo/node/rntuple_test32.js demo/node/rntuple_test32.root demo/node/rntuple_test32.json
 
 
@@ -241,5 +243,6 @@ jobs:
           node demo/node/rntuple_buffer_test.js
           node demo/node/rntuple_test.js demo/node/rntuple_test.root
           node demo/node/tree_int64_test.js demo/node/tree_int64_test.root
+          node demo/node/tree_draw_range.js demo/node/rntuple_test.root
           node demo/node/rntuple_test32.js demo/node/rntuple_test32.root demo/node/rntuple_test32.json
 

demo/node/tree_draw_range.js

@@ -0,0 +1,33 @@
+import { version, openFile } from 'jsroot';
+import { rntupleDraw } from 'jsroot/rntuple';
+
+// check that automatic histogram range of draw expression includes all values
+
+console.log(`JSROOT version ${version}`);
+
+let filename = './rntuple_test.root',
+    any_error = false;
+
+if (process?.argv && process.argv[2])
+   filename = process.argv[2];
+
+const file = await openFile(filename),
+      rntuple = await file.readObject('Data');
+
+// first value of DoubleField is 0, which is minimal value, in second expression it is maximal value
+for (const expr of ['DoubleField', '5 - DoubleField']) {
+   const hist = await rntupleDraw(rntuple, expr),
+         underflow = hist.fArray[0],
+         overflow = hist.fArray[hist.fXaxis.fNbins + 1];
+   if (underflow || overflow) {
+      any_error = true;
+      console.error(`FAILURE: drawing '${expr}' has range [${hist.fXaxis.fXmin}, ${hist.fXaxis.fXmax}], underflow ${underflow}, overflow ${overflow}`);
+   } else
+      console.log(`OK: drawing '${expr}' has range [${hist.fXaxis.fXmin}, ${hist.fXaxis.fXmax}]`);
+}
+
+if (any_error) {
+   console.error('\nFAILURE when checking histogram range');
+   process.exit(1);
+} else
+   console.log('\nTest OK');

modules/tree.mjs

@@ -1230,7 +1230,7 @@ class TDrawSelector extends TSelector {
          res.max = this.hist_args[axisid * 3 + 2];
       } else {
          let is_any = false;
-         for (let i = 1; i < arr.length; ++i) {
+         for (let i = 0; i < arr.length; ++i) {
             const v = arr[i];
             if (!Number.isFinite(v))
                continue;