From ba2f3a156ebc9ce3e6b6e59e231a5c2847163671 Mon Sep 17 00:00:00 2001
From: Christian Ehrlicher <ch.ehrlicher@gmx.de>
Date: Sun, 12 Nov 2017 13:33:25 +0100
Subject: QTreeView: recalculate row heights in hide/showColumn()

When calling QTreeView::hideColumn() the row heights are not
recalculated. This can lead to rows which are unnecessarily high due to
hidden columns may contain large (e.g. multiline) content. The same
applies to showColumn() - there the row might be to small.
Hiding columns directly via QTreeView::header()->hideSection() is not
covered by this patch since QHeaderView has no way to inform about
newly shown/hidden sections.

Task-number: QTBUG-8376
Change-Id: I20b1198e56e403ab8cf649af76e5e2280821dd68
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
---
 src/widgets/itemviews/qtreeview.cpp                |  6 +++
 .../widgets/itemviews/qtreeview/tst_qtreeview.cpp  | 47 ++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/src/widgets/itemviews/qtreeview.cpp b/src/widgets/itemviews/qtreeview.cpp
index 2abb1a9c14..805b855b9d 100644
--- a/src/widgets/itemviews/qtreeview.cpp
+++ b/src/widgets/itemviews/qtreeview.cpp
@@ -736,7 +736,10 @@ void QTreeView::dataChanged(const QModelIndex &topLeft, const QModelIndex &botto
 void QTreeView::hideColumn(int column)
 {
     Q_D(QTreeView);
+    if (d->header->isSectionHidden(column))
+        return;
     d->header->hideSection(column);
+    doItemsLayout();
 }
 
 /*!
@@ -747,7 +750,10 @@ void QTreeView::hideColumn(int column)
 void QTreeView::showColumn(int column)
 {
     Q_D(QTreeView);
+    if (!d->header->isSectionHidden(column))
+        return;
     d->header->showSection(column);
+    doItemsLayout();
 }
 
 /*!
diff --git a/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp b/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
index 6ee0e50cce..3260d7c968 100644
--- a/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
+++ b/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
@@ -193,6 +193,7 @@ private slots:
     void taskQTBUG_37813_crash();
     void taskQTBUG_45697_crash();
     void taskQTBUG_7232_AllowUserToControlSingleStep();
+    void taskQTBUG_8376();
     void testInitialFocus();
 };
 
@@ -4399,5 +4400,51 @@ void tst_QTreeView::taskQTBUG_7232_AllowUserToControlSingleStep()
     QCOMPARE(hStep1, t.horizontalScrollBar()->singleStep());
 }
 
+static void fillModeltaskQTBUG_8376(QAbstractItemModel &model)
+{
+    model.insertRow(0);
+    model.insertColumn(0);
+    model.insertColumn(1);
+    QModelIndex index = model.index(0, 0);
+    model.setData(index, "Level0");
+    {
+        model.insertRow(0, index);
+        model.insertRow(1, index);
+        model.insertColumn(0, index);
+        model.insertColumn(1, index);
+
+        QModelIndex idx;
+        idx = model.index(0, 0, index);
+        model.setData(idx, "Level1");
+
+        idx = model.index(0, 1, index);
+        model.setData(idx, "very\nvery\nhigh\ncell");
+    }
+}
+
+void tst_QTreeView::taskQTBUG_8376()
+{
+    QTreeView tv;
+    QStandardItemModel model;
+    fillModeltaskQTBUG_8376(model);
+    tv.setModel(&model);
+    tv.expandAll(); // init layout
+
+    QModelIndex idxLvl0 = model.index(0, 0);
+    QModelIndex idxLvl1 = model.index(0, 1, idxLvl0);
+    const int rowHeightLvl0 = tv.rowHeight(idxLvl0);
+    const int rowHeightLvl1Visible = tv.rowHeight(idxLvl1);
+    QVERIFY(rowHeightLvl0 < rowHeightLvl1Visible);
+
+    tv.hideColumn(1);
+    const int rowHeightLvl1Hidden = tv.rowHeight(idxLvl1);
+    QCOMPARE(rowHeightLvl0, rowHeightLvl1Hidden);
+
+    tv.showColumn(1);
+    const int rowHeightLvl1Visible2 = tv.rowHeight(idxLvl1);
+    QCOMPARE(rowHeightLvl1Visible, rowHeightLvl1Visible2);
+}
+
+
 QTEST_MAIN(tst_QTreeView)
 #include "tst_qtreeview.moc"
-- 
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