DialogButtonBox: add contentWidth and contentHeight

This is a follow-up to f1f884d3, which mentioned that:

    This can be fixed properly in dev by providing separate contentWidth
    and contentHeight properties that cleanly propagate the content size
    to QML.

[ChangeLog][Controls][DialogButtonBox] Added contentWidth and
contentHeight properties.

Change-Id: I4b53702568c55d666bccb587af9fe8c8eba0b63d
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

8 files changed, 218 insertions, 40 deletions

diff --git a/src/imports/controls/DialogButtonBox.qml b/src/imports/controls/DialogButtonBox.qml
index feff1492..e66d41e7 100644
--- a/src/imports/controls/DialogButtonBox.qml
+++ b/src/imports/controls/DialogButtonBox.qml
@@ -41,9 +41,9 @@ T.DialogButtonBox {
     id: control
 
     implicitWidth: Math.max(background ? background.implicitWidth : 0,
-                            contentItem.implicitWidth + leftPadding + rightPadding)
+                            (control.count === 1 ? contentWidth * 2 : contentWidth) + leftPadding + rightPadding)
     implicitHeight: Math.max(background ? background.implicitHeight : 0,
-                             contentItem.implicitHeight + topPadding + bottomPadding)
+                             contentHeight + topPadding + bottomPadding)
 
     spacing: 1
     padding: 12
@@ -54,9 +54,6 @@ T.DialogButtonBox {
     }
 
     contentItem: ListView {
-        implicitWidth: control.count === 1 ? 200 : contentWidth
-        implicitHeight: 40
-
         model: control.contentModel
         spacing: control.spacing
         orientation: ListView.Horizontal
diff --git a/src/imports/controls/fusion/DialogButtonBox.qml b/src/imports/controls/fusion/DialogButtonBox.qml
index cfd4be3e..3cf842ff 100644
--- a/src/imports/controls/fusion/DialogButtonBox.qml
+++ b/src/imports/controls/fusion/DialogButtonBox.qml
@@ -45,9 +45,9 @@ T.DialogButtonBox {
     id: control
 
     implicitWidth: Math.max(background ? background.implicitWidth : 0,
-                            contentItem.implicitWidth + leftPadding + rightPadding)
+                            contentWidth + leftPadding + rightPadding)
     implicitHeight: Math.max(background ? background.implicitHeight : 0,
-                             contentItem.implicitHeight + topPadding + bottomPadding)
+                             contentHeight + topPadding + bottomPadding)
 
     spacing: 6
     padding: 6
@@ -56,9 +56,6 @@ T.DialogButtonBox {
     delegate: Button { }
 
     contentItem: ListView {
-        implicitWidth: contentWidth
-        implicitHeight: 24
-
         model: control.contentModel
         spacing: control.spacing
         orientation: ListView.Horizontal
diff --git a/src/imports/controls/imagine/DialogButtonBox.qml b/src/imports/controls/imagine/DialogButtonBox.qml
index eb756548..e58d5645 100644
--- a/src/imports/controls/imagine/DialogButtonBox.qml
+++ b/src/imports/controls/imagine/DialogButtonBox.qml
@@ -44,9 +44,9 @@ T.DialogButtonBox {
     id: control
 
     implicitWidth: Math.max(background ? background.implicitWidth : 0,
-                            contentItem.implicitWidth + leftPadding + rightPadding)
+                            (control.count === 1 ? contentWidth * 2 : contentWidth) + leftPadding + rightPadding)
     implicitHeight: Math.max(background ? background.implicitHeight : 0,
-                             contentItem.implicitHeight + topPadding + bottomPadding)
+                             contentHeight + topPadding + bottomPadding)
 
     topPadding: background ? background.topPadding : 0
     leftPadding: background ? background.leftPadding : 0
@@ -60,9 +60,6 @@ T.DialogButtonBox {
     }
 
     contentItem: ListView {
-        implicitWidth: control.count === 1 ? 200 : contentWidth
-        implicitHeight: 32
-
         model: control.contentModel
         spacing: control.spacing
         orientation: ListView.Horizontal
diff --git a/src/imports/controls/material/DialogButtonBox.qml b/src/imports/controls/material/DialogButtonBox.qml
index 7c217f59..1eeb07c5 100644
--- a/src/imports/controls/material/DialogButtonBox.qml
+++ b/src/imports/controls/material/DialogButtonBox.qml
@@ -45,9 +45,9 @@ T.DialogButtonBox {
     id: control
 
     implicitWidth: Math.max(background ? background.implicitWidth : 0,
-                            contentItem.implicitWidth + leftPadding + rightPadding)
+                            contentWidth + leftPadding + rightPadding)
     implicitHeight: Math.max(background ? background.implicitHeight : 0,
-                             contentItem.implicitHeight + topPadding + bottomPadding)
+                             contentHeight + topPadding + bottomPadding)
 
     spacing: 8
     padding: 8
@@ -60,9 +60,6 @@ T.DialogButtonBox {
     delegate: Button { flat: true }
 
     contentItem: ListView {
-        implicitWidth: contentWidth
-        implicitHeight: control.Material.buttonHeight
-
         model: control.contentModel
         spacing: control.spacing
         orientation: ListView.Horizontal
diff --git a/src/imports/controls/universal/DialogButtonBox.qml b/src/imports/controls/universal/DialogButtonBox.qml
index 6dff51d1..26f6ea1f 100644
--- a/src/imports/controls/universal/DialogButtonBox.qml
+++ b/src/imports/controls/universal/DialogButtonBox.qml
@@ -43,9 +43,9 @@ T.DialogButtonBox {
     id: control
 
     implicitWidth: Math.max(background ? background.implicitWidth : 0,
-                            contentItem.implicitWidth + leftPadding + rightPadding)
+                            (control.count === 1 ? contentWidth * 2 : contentWidth) + leftPadding + rightPadding)
     implicitHeight: Math.max(background ? background.implicitHeight : 0,
-                             contentItem.implicitHeight + topPadding + bottomPadding)
+                             contentHeight + topPadding + bottomPadding)
 
     spacing: 4
     padding: 24
@@ -58,9 +58,6 @@ T.DialogButtonBox {
     }
 
     contentItem: ListView {
-        implicitWidth: control.count === 1 ? 200 : contentWidth
-        implicitHeight: 32
-
         model: control.contentModel
         spacing: control.spacing
         orientation: ListView.Horizontal
diff --git a/src/quicktemplates2/qquickdialogbuttonbox.cpp b/src/quicktemplates2/qquickdialogbuttonbox.cpp
index 7e178f2a..fb07f587 100644
--- a/src/quicktemplates2/qquickdialogbuttonbox.cpp
+++ b/src/quicktemplates2/qquickdialogbuttonbox.cpp
@@ -198,7 +198,11 @@ static QQuickDialogButtonBox::ButtonLayout platformButtonLayout()
 }
 
 QQuickDialogButtonBoxPrivate::QQuickDialogButtonBoxPrivate()
-    : alignment(0),
+    : hasContentWidth(false),
+      hasContentHeight(false),
+      contentWidth(0),
+      contentHeight(0),
+      alignment(0),
       position(QQuickDialogButtonBox::Footer),
       standardButtons(QPlatformDialogHelper::NoButton),
       buttonLayout(platformButtonLayout()),
@@ -208,14 +212,18 @@ QQuickDialogButtonBoxPrivate::QQuickDialogButtonBoxPrivate()
 
 void QQuickDialogButtonBoxPrivate::itemImplicitWidthChanged(QQuickItem *item)
 {
-    Q_UNUSED(item);
-    resizeContent();
+    if (item == contentItem)
+        resizeContent();
+    else
+        updateContentWidth();
 }
 
 void QQuickDialogButtonBoxPrivate::itemImplicitHeightChanged(QQuickItem *item)
 {
-    Q_UNUSED(item);
-    resizeContent();
+    if (item == contentItem)
+        resizeContent();
+    else
+        updateContentHeight();
 }
 
 // adapted from QStyle::alignedRect()
@@ -226,7 +234,7 @@ static QRectF alignedRect(Qt::LayoutDirection direction, Qt::Alignment alignment
     qreal y = rectangle.y();
     qreal w = size.width();
     qreal h = size.height();
-    if ((alignment & Qt::AlignVCenter) == Qt::AlignVCenter)
+    if ((alignment & Qt::AlignVCenter) == Qt::AlignVCenter || (alignment & Qt::AlignVertical_Mask) == 0)
         y += (rectangle.size().height() - h) / 2;
     else if ((alignment & Qt::AlignBottom) == Qt::AlignBottom)
         y += rectangle.size().height() - h;
@@ -244,11 +252,8 @@ void QQuickDialogButtonBoxPrivate::resizeContent()
         return;
 
     QRectF geometry = q->boundingRect().adjusted(q->leftPadding(), q->topPadding(), -q->rightPadding(), -q->bottomPadding());
-    if (alignment != 0) {
-        qreal cw = (alignment & Qt::AlignHorizontal_Mask) == 0 ? q->availableWidth() : contentItem->property("contentWidth").toReal();
-        qreal ch = (alignment & Qt::AlignVertical_Mask) == 0 ? q->availableHeight() : contentItem->property("contentHeight").toReal();
-        geometry = alignedRect(q->isMirrored() ? Qt::RightToLeft : Qt::LeftToRight, alignment, QSizeF(cw, ch), geometry);
-    }
+    if (alignment != 0)
+        geometry = alignedRect(q->isMirrored() ? Qt::RightToLeft : Qt::LeftToRight, alignment, QSizeF(contentWidth, contentHeight), geometry);
 
     contentItem->setPosition(geometry.topLeft());
     contentItem->setSize(geometry.size());
@@ -265,8 +270,7 @@ void QQuickDialogButtonBoxPrivate::updateLayout()
     const int valign = alignment & Qt::AlignVertical_Mask;
 
     QVector<QQuickAbstractButton *> buttons;
-    const qreal maxItemWidth = ((contentItem ? contentItem->width() : q->availableWidth()) - qMax(0, count - 1) * spacing) / count;
-    const qreal maxItemHeight = contentItem ? contentItem->height() : q->availableHeight();
+    const qreal itemWidth = (contentWidth - qMax(0, count - 1) * spacing) / count;
 
     for (int i = 0; i < count; ++i) {
         QQuickItem *item = q->itemAt(i);
@@ -274,11 +278,11 @@ void QQuickDialogButtonBoxPrivate::updateLayout()
             QQuickItemPrivate *p = QQuickItemPrivate::get(item);
             if (!p->widthValid) {
                 if (!halign)
-                    item->setWidth(maxItemWidth);
+                    item->setWidth(itemWidth);
                 else
                     item->resetWidth();
                 if (!valign)
-                    item->setHeight(maxItemHeight);
+                    item->setHeight(contentHeight);
                 else
                     item->resetHeight();
                 p->widthValid = false;
@@ -324,6 +328,89 @@ void QQuickDialogButtonBoxPrivate::updateLayout()
         q->insertItem(i, buttons.at(i));
 }
 
+qreal QQuickDialogButtonBoxPrivate::getContentWidth() const
+{
+    Q_Q(const QQuickDialogButtonBox);
+    const int count = contentModel->count();
+    const qreal totalSpacing = qMax(0, count - 1) * spacing;
+    qreal totalWidth = totalSpacing;
+    qreal maxWidth = 0;
+    for (int i = 0; i < count; ++i) {
+        QQuickItem *item = q->itemAt(i);
+        if (item) {
+            totalWidth += item->implicitWidth();
+            maxWidth = qMax(maxWidth, item->implicitWidth());
+        }
+    }
+    if ((alignment & Qt::AlignHorizontal_Mask) == 0)
+        totalWidth = qMax(totalWidth, count * maxWidth + totalSpacing);
+    return totalWidth;
+}
+
+qreal QQuickDialogButtonBoxPrivate::getContentHeight() const
+{
+    Q_Q(const QQuickDialogButtonBox);
+    const int count = contentModel->count();
+    qreal maxHeight = 0;
+    for (int i = 0; i < count; ++i) {
+        QQuickItem *item = q->itemAt(i);
+        if (item)
+            maxHeight = qMax(maxHeight, item->implicitHeight());
+    }
+    return maxHeight;
+}
+
+void QQuickDialogButtonBoxPrivate::updateContentWidth()
+{
+    Q_Q(QQuickDialogButtonBox);
+    if (hasContentWidth)
+        return;
+
+    const qreal oldContentWidth = contentWidth;
+    contentWidth = getContentWidth();
+    if (qFuzzyCompare(contentWidth, oldContentWidth))
+        return;
+
+    emit q->contentWidthChanged();
+}
+
+void QQuickDialogButtonBoxPrivate::updateContentHeight()
+{
+    Q_Q(QQuickDialogButtonBox);
+    if (hasContentHeight)
+        return;
+
+    const qreal oldContentHeight = contentHeight;
+    contentHeight = getContentHeight();
+    if (qFuzzyCompare(contentHeight, oldContentHeight))
+        return;
+
+    emit q->contentHeightChanged();
+}
+
+void QQuickDialogButtonBoxPrivate::updateContentSize()
+{
+    Q_Q(QQuickDialogButtonBox);
+    if (hasContentWidth && hasContentHeight)
+        return;
+
+    const qreal oldContentWidth = contentWidth;
+    if (!hasContentWidth)
+        contentWidth = getContentWidth();
+
+    const qreal oldContentHeight = contentHeight;
+    if (!hasContentHeight)
+        contentHeight = getContentHeight();
+
+    const bool widthChanged = !qFuzzyCompare(contentWidth, oldContentWidth);
+    const bool heightChanged = !qFuzzyCompare(contentHeight, oldContentHeight);
+
+    if (widthChanged)
+        emit q->contentWidthChanged();
+    if (heightChanged)
+        emit q->contentHeightChanged();
+}
+
 void QQuickDialogButtonBoxPrivate::handleClick()
 {
     Q_Q(QQuickDialogButtonBox);
@@ -647,6 +734,85 @@ void QQuickDialogButtonBox::resetButtonLayout()
     setButtonLayout(platformButtonLayout());
 }
 
+/*!
+    \since QtQuick.Controls 2.5 (Qt 5.12)
+    \qmlproperty real QtQuick.Controls::DialogButtonBox::contentWidth
+
+    This property holds the content width. It is used for calculating the total
+    implicit width of the button box.
+
+    Unless explicitly overridden, the content width is automatically calculated
+    based on the total implicit width of the buttons and the \l {Control::}{spacing}
+    of the button box.
+
+    \sa contentHeight
+*/
+qreal QQuickDialogButtonBox::contentWidth() const
+{
+    Q_D(const QQuickDialogButtonBox);
+    return d->contentWidth;
+}
+
+void QQuickDialogButtonBox::setContentWidth(qreal width)
+{
+    Q_D(QQuickDialogButtonBox);
+    d->hasContentWidth = true;
+    if (qFuzzyCompare(d->contentWidth, width))
+        return;
+
+    d->contentWidth = width;
+    emit contentWidthChanged();
+}
+
+void QQuickDialogButtonBox::resetContentWidth()
+{
+    Q_D(QQuickDialogButtonBox);
+    if (!d->hasContentWidth)
+        return;
+
+    d->hasContentWidth = false;
+    d->updateContentWidth();
+}
+
+/*!
+    \since QtQuick.Controls 2.5 (Qt 5.12)
+    \qmlproperty real QtQuick.Controls::DialogButtonBox::contentHeight
+
+    This property holds the content height. It is used for calculating the total
+    implicit height of the button box.
+
+    Unless explicitly overridden, the content height is automatically calculated
+    based on the maximum implicit height of the buttons.
+
+    \sa contentWidth
+*/
+qreal QQuickDialogButtonBox::contentHeight() const
+{
+    Q_D(const QQuickDialogButtonBox);
+    return d->contentHeight;
+}
+
+void QQuickDialogButtonBox::setContentHeight(qreal height)
+{
+    Q_D(QQuickDialogButtonBox);
+    d->hasContentHeight = true;
+    if (qFuzzyCompare(d->contentHeight, height))
+        return;
+
+    d->contentHeight = height;
+    emit contentHeightChanged();
+}
+
+void QQuickDialogButtonBox::resetContentHeight()
+{
+    Q_D(QQuickDialogButtonBox);
+    if (!d->hasContentHeight)
+        return;
+
+    d->hasContentHeight = false;
+    d->updateContentHeight();
+}
+
 void QQuickDialogButtonBox::updatePolish()
 {
     Q_D(QQuickDialogButtonBox);
@@ -691,6 +857,7 @@ void QQuickDialogButtonBox::itemAdded(int index, QQuickItem *item)
         QObjectPrivate::connect(button, &QQuickAbstractButton::clicked, d, &QQuickDialogButtonBoxPrivate::handleClick);
     if (QQuickDialogButtonBoxAttached *attached = qobject_cast<QQuickDialogButtonBoxAttached *>(qmlAttachedPropertiesObject<QQuickDialogButtonBox>(item, false)))
         QQuickDialogButtonBoxAttachedPrivate::get(attached)->setButtonBox(this);
+    d->updateContentSize();
     if (isComponentComplete())
         polish();
 }
@@ -703,6 +870,7 @@ void QQuickDialogButtonBox::itemRemoved(int index, QQuickItem *item)
         QObjectPrivate::disconnect(button, &QQuickAbstractButton::clicked, d, &QQuickDialogButtonBoxPrivate::handleClick);
     if (QQuickDialogButtonBoxAttached *attached = qobject_cast<QQuickDialogButtonBoxAttached *>(qmlAttachedPropertiesObject<QQuickDialogButtonBox>(item, false)))
         QQuickDialogButtonBoxAttachedPrivate::get(attached)->setButtonBox(nullptr);
+    d->updateContentSize();
     if (isComponentComplete())
         polish();
 }
diff --git a/src/quicktemplates2/qquickdialogbuttonbox_p.h b/src/quicktemplates2/qquickdialogbuttonbox_p.h
index df302e54..0edc671d 100644
--- a/src/quicktemplates2/qquickdialogbuttonbox_p.h
+++ b/src/quicktemplates2/qquickdialogbuttonbox_p.h
@@ -68,6 +68,8 @@ class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickDialogButtonBox : public QQuickCont
     Q_PROPERTY(QQmlComponent *delegate READ delegate WRITE setDelegate NOTIFY delegateChanged FINAL)
     // 2.5 (Qt 5.12)
     Q_PROPERTY(ButtonLayout buttonLayout READ buttonLayout WRITE setButtonLayout RESET resetButtonLayout NOTIFY buttonLayoutChanged FINAL REVISION 5)
+    Q_PROPERTY(qreal contentWidth READ contentWidth WRITE setContentWidth RESET resetContentWidth NOTIFY contentWidthChanged FINAL REVISION 5)
+    Q_PROPERTY(qreal contentHeight READ contentHeight WRITE setContentHeight RESET resetContentHeight NOTIFY contentHeightChanged FINAL REVISION 5)
     Q_FLAGS(QPlatformDialogHelper::StandardButtons)
 
 public:
@@ -114,6 +116,14 @@ public:
     void setButtonLayout(ButtonLayout layout);
     void resetButtonLayout();
 
+    qreal contentWidth() const;
+    void setContentWidth(qreal width);
+    void resetContentWidth();
+
+    qreal contentHeight() const;
+    void setContentHeight(qreal height);
+    void resetContentHeight();
+
 Q_SIGNALS:
     void accepted();
     void rejected();
@@ -129,6 +139,8 @@ Q_SIGNALS:
     Q_REVISION(3) void discarded();
     // 2.5 (Qt 5.12)
     Q_REVISION(5) void buttonLayoutChanged();
+    Q_REVISION(5) void contentWidthChanged();
+    Q_REVISION(5) void contentHeightChanged();
 
 protected:
     void updatePolish() override;
diff --git a/src/quicktemplates2/qquickdialogbuttonbox_p_p.h b/src/quicktemplates2/qquickdialogbuttonbox_p_p.h
index 3c761d6b..b9cbe5b7 100644
--- a/src/quicktemplates2/qquickdialogbuttonbox_p_p.h
+++ b/src/quicktemplates2/qquickdialogbuttonbox_p_p.h
@@ -69,12 +69,25 @@ public:
     void itemImplicitHeightChanged(QQuickItem *item) override;
 
     void resizeContent() override;
+
     void updateLayout();
+
+    qreal getContentWidth() const;
+    qreal getContentHeight() const;
+
+    void updateContentWidth();
+    void updateContentHeight();
+    void updateContentSize();
+
     void handleClick();
 
     QQuickAbstractButton *createStandardButton(QPlatformDialogHelper::StandardButton button);
     void removeStandardButtons();
 
+    bool hasContentWidth;
+    bool hasContentHeight;
+    qreal contentWidth;
+    qreal contentHeight;
     Qt::Alignment alignment;
     QQuickDialogButtonBox::Position position;
     QPlatformDialogHelper::StandardButtons standardButtons;