ToolTip: use contentWidth of Text contentItem to account for newlines

By default, QQuickPopupItem uses the implicitWidth of its contentItem,
which is too large in the case of a ToolTip with newlines in the text.
In that case, contentWidth refers to the width of the text including
newlines, so we use that instead.

[ChangeLog][Controls][ToolTip] The implicit width of ToolTips now
accounts for newlines in the text. If you want to use the old behavior,
set ToolTip's contentWidth to implicitContentWidth.

Fixes: QTBUG-83630
Change-Id: I7ca3805429acb68a13ead8f3545bb84a51fb1b72
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit a063cd0be5e8f108a0084831856f4af8c0e9159c)
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

6 files changed, 233 insertions, 6 deletions

diff --git a/src/quicktemplates2/qquickpane_p_p.h b/src/quicktemplates2/qquickpane_p_p.h
index 579371f4..4d82cc32 100644
--- a/src/quicktemplates2/qquickpane_p_p.h
+++ b/src/quicktemplates2/qquickpane_p_p.h
@@ -75,7 +75,7 @@ public:
 
     void contentChildrenChange();
 
-    void updateContentWidth();
+    virtual void updateContentWidth();
     void updateContentHeight();
 
     bool hasContentWidth = false;
diff --git a/src/quicktemplates2/qquicktooltip.cpp b/src/quicktemplates2/qquicktooltip.cpp
index 19c4cc83..cb08127c 100644
--- a/src/quicktemplates2/qquicktooltip.cpp
+++ b/src/quicktemplates2/qquicktooltip.cpp
@@ -38,6 +38,7 @@
 #include "qquickpopup_p_p.h"
 #include "qquickpopupitem_p_p.h"
 #include "qquickcontrol_p_p.h"
+#include "qquicktooltippopupitem_p_p.h"
 
 #include <QtCore/qbasictimer.h>
 #include <QtQml/qqmlinfo.h>
@@ -124,6 +125,8 @@ class QQuickToolTipPrivate : public QQuickPopupPrivate
     Q_DECLARE_PUBLIC(QQuickToolTip)
 
 public:
+    void init() override;
+
     void startDelay();
     void stopDelay();
 
@@ -137,6 +140,19 @@ public:
     QBasicTimer timeoutTimer;
 };
 
+void QQuickToolTipPrivate::init()
+{
+    Q_Q(QQuickToolTip);
+    popupItem = new QQuickToolTipPopupItem(q);
+    popupItem->setVisible(false);
+    q->setParentItem(qobject_cast<QQuickItem *>(parent));
+    connectToPopupItem();
+
+    allowVerticalFlip = true;
+    allowHorizontalFlip = true;
+    popupItem->setHoverEnabled(false); // QTBUG-63644
+}
+
 void QQuickToolTipPrivate::startDelay()
 {
     Q_Q(QQuickToolTip);
@@ -165,9 +181,7 @@ QQuickToolTip::QQuickToolTip(QQuickItem *parent)
     : QQuickPopup(*(new QQuickToolTipPrivate), parent)
 {
     Q_D(QQuickToolTip);
-    d->allowVerticalFlip = true;
-    d->allowHorizontalFlip = true;
-    d->popupItem->setHoverEnabled(false); // QTBUG-63644
+    d->init();
 }
 
 /*!
diff --git a/src/quicktemplates2/qquicktooltippopupitem.cpp b/src/quicktemplates2/qquicktooltippopupitem.cpp
new file mode 100644
index 00000000..49455ca9
--- /dev/null
+++ b/src/quicktemplates2/qquicktooltippopupitem.cpp
@@ -0,0 +1,106 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Quick Templates 2 module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:COMM$
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** $QT_END_LICENSE$
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+****************************************************************************/
+
+#include "qquicktooltippopupitem_p_p.h"
+
+#include <QtQuickTemplates2/private/qquickpopup_p.h>
+
+QT_BEGIN_NAMESPACE
+
+QQuickToolTipPopupItemPrivate::QQuickToolTipPopupItemPrivate(QQuickPopup *popup)
+    : QQuickPopupItemPrivate(popup)
+{
+}
+
+qreal QQuickToolTipPopupItemPrivate::getContentWidth() const
+{
+    auto textItem = qobject_cast<QQuickText*>(contentItem);
+    if (textItem)
+        return textItem->contentWidth();
+
+    return contentItem ? contentItem->implicitWidth() : 0;
+}
+
+void QQuickToolTipPopupItemPrivate::updateContentWidth()
+{
+    Q_Q(QQuickToolTipPopupItem);
+    // Don't need to calculate the implicit contentWidth if an explicit one was set.
+    if (hasContentWidth)
+        return;
+
+    auto textItem = qobject_cast<QQuickText*>(contentItem);
+    if (!textItem) {
+        // It's not a Text item, so use the base contentWidth logic (i.e. use implicitWidth).
+        QQuickPopupItemPrivate::updateContentWidth();
+        return;
+    }
+
+    const qreal oldContentWidth = contentWidth;
+    const qreal newContentWidth = textItem->contentWidth();
+    if (qFuzzyCompare(oldContentWidth, newContentWidth))
+        return;
+
+    contentWidth = newContentWidth;
+    q->contentSizeChange(QSizeF(contentWidth, contentHeight), QSizeF(oldContentWidth, contentHeight));
+    emit q->contentWidthChanged();
+}
+
+QQuickToolTipPopupItem::QQuickToolTipPopupItem(QQuickPopup *popup)
+    : QQuickPopupItem(*(new QQuickToolTipPopupItemPrivate(popup)))
+{
+}
+
+void QQuickToolTipPopupItem::contentItemChange(QQuickItem *newItem, QQuickItem *oldItem)
+{
+    Q_D(QQuickToolTipPopupItem);
+    QQuickPopupItem::contentItemChange(newItem, oldItem);
+
+    // Text's implicitWidth does not account for newlines and hence is too large,
+    // so we need to listen to contentWidth's change signals.
+    auto oldTextItem = qobject_cast<QQuickText*>(oldItem);
+    if (oldTextItem) {
+        QObjectPrivate::disconnect(oldTextItem, &QQuickText::contentWidthChanged,
+            d, &QQuickToolTipPopupItemPrivate::updateContentWidth);
+    }
+
+    auto newTextItem = qobject_cast<QQuickText*>(newItem);
+    if (newTextItem) {
+        QObjectPrivate::connect(newTextItem, &QQuickText::contentWidthChanged,
+            d, &QQuickToolTipPopupItemPrivate::updateContentWidth);
+    }
+}
+
+QT_END_NAMESPACE
diff --git a/src/quicktemplates2/qquicktooltippopupitem_p_p.h b/src/quicktemplates2/qquicktooltippopupitem_p_p.h
new file mode 100644
index 00000000..a86dfd9d
--- /dev/null
+++ b/src/quicktemplates2/qquicktooltippopupitem_p_p.h
@@ -0,0 +1,87 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Quick Templates 2 module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:COMM$
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** $QT_END_LICENSE$
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+**
+****************************************************************************/
+
+#ifndef QQUICKTOOLTIPPOPUPITEM_P_P_H
+#define QQUICKTOOLTIPPOPUPITEM_P_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtQuickTemplates2/private/qquickpopupitem_p.h>
+#include <QtQuickTemplates2/private/qquickpopupitem_p_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QQuickPopup;
+class QQuickToolTipPopupItemPrivate;
+
+class QQuickToolTipPopupItem : public QQuickPopupItem
+{
+    Q_OBJECT
+
+public:
+    explicit QQuickToolTipPopupItem(QQuickPopup *popup);
+
+protected:
+    void contentItemChange(QQuickItem *newItem, QQuickItem *oldItem) override;
+
+private:
+    Q_DISABLE_COPY(QQuickToolTipPopupItem)
+    Q_DECLARE_PRIVATE(QQuickToolTipPopupItem)
+};
+
+class QQuickToolTipPopupItemPrivate : public QQuickPopupItemPrivate
+{
+    Q_DECLARE_PUBLIC(QQuickToolTipPopupItem)
+
+public:
+    QQuickToolTipPopupItemPrivate(QQuickPopup *popup);
+
+    qreal getContentWidth() const override;
+    void updateContentWidth() override;
+};
+
+QT_END_NAMESPACE
+
+#endif // QQUICKTOOLTIPPOPUPITEM_P_P_H
diff --git a/src/quicktemplates2/quicktemplates2.pri b/src/quicktemplates2/quicktemplates2.pri
index ba09591b..28eec3ef 100644
--- a/src/quicktemplates2/quicktemplates2.pri
+++ b/src/quicktemplates2/quicktemplates2.pri
@@ -99,6 +99,7 @@ HEADERS += \
     $$PWD/qquicktoolbutton_p.h \
     $$PWD/qquicktoolseparator_p.h \
     $$PWD/qquicktooltip_p.h \
+    $$PWD/qquicktooltippopupitem_p_p.h \
     $$PWD/qquickvelocitycalculator_p_p.h
 
 SOURCES += \
@@ -172,6 +173,7 @@ SOURCES += \
     $$PWD/qquicktoolbutton.cpp \
     $$PWD/qquicktoolseparator.cpp \
     $$PWD/qquicktooltip.cpp \
+    $$PWD/qquicktooltippopupitem.cpp \
     $$PWD/qquickvelocitycalculator.cpp
 
 qtConfig(quick-listview):qtConfig(quick-pathview) {
diff --git a/tests/auto/controls/data/tst_tooltip.qml b/tests/auto/controls/data/tst_tooltip.qml
index 6d45b09d..154eb2bf 100644
--- a/tests/auto/controls/data/tst_tooltip.qml
+++ b/tests/auto/controls/data/tst_tooltip.qml
@@ -75,6 +75,11 @@ TestCase {
         SignalSpy { }
     }
 
+    Component {
+        id: itemComponent
+        Item {}
+    }
+
     QtObject {
         id: object
     }
@@ -218,8 +223,8 @@ TestCase {
     }
 
     function test_warning() {
-        ignoreWarning(Qt.resolvedUrl("tst_tooltip.qml") + ":78:5: QML QtObject: ToolTip must be attached to an Item")
-        ignoreWarning("<Unknown File>:1:30: QML ToolTip: cannot find any window to open popup in.")
+        ignoreWarning(new RegExp(".*QML QtObject: ToolTip must be attached to an Item"))
+        ignoreWarning(new RegExp(".*QML ToolTip: cannot find any window to open popup in."))
         object.ToolTip.show("") // don't crash (QTBUG-56243)
     }
 
@@ -474,4 +479,17 @@ TestCase {
         compare(item.ToolTip.toolTip.contentItem.wrapMode, Text.Wrap)
         verify(item.ToolTip.toolTip.contentItem.width < item.ToolTip.toolTip.contentItem.implicitWidth)
     }
+
+    // QTBUG-83630: Test that newlines are accounted for in the implicit contentWidth.
+    function test_newLines() {
+        var item = createTemporaryObject(itemComponent, testCase)
+        verify(item)
+
+        item.ToolTip.show("This is one line of text\nThis is another line of text")
+
+        // The implicitWidth of the Text item for the text above will be larger than
+        // its contentWidth. ToolTip's implicitWidth uses contentWidth in its calculation,
+        // so we check that it's less than the Text's implicitWidth.
+        verify(item.ToolTip.toolTip.implicitWidth < item.ToolTip.toolTip.contentItem.implicitWidth)
+    }
 }