Add support for showing tooltips when the legend text is truncated

Change-Id: Ie0b90489eb51633a0294db12410f9056f740d086
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@theqtcompany.com>

5 files changed, 78 insertions, 4 deletions

diff --git a/src/charts/legend/legendmarkeritem.cpp b/src/charts/legend/legendmarkeritem.cpp
index ae5eb5ef..125199ea 100644
--- a/src/charts/legend/legendmarkeritem.cpp
+++ b/src/charts/legend/legendmarkeritem.cpp
@@ -124,9 +124,14 @@ void LegendMarkerItem::setGeometry(const QRectF &rect)
     qreal width = rect.width();
     qreal x = m_margin + m_markerRect.width() + m_space + m_margin;
     QRectF truncatedRect;
+    const QString html = ChartPresenter::truncatedText(m_textItem->font(), m_label, qreal(0.0),
+                                                       width - x, rect.height(), truncatedRect);
+    m_textItem->setHtml(html);
+    if (m_marker->m_legend->showToolTips() && html != m_label)
+        m_textItem->setToolTip(m_label);
+    else
+        m_textItem->setToolTip(QString());
 
-    m_textItem->setHtml(ChartPresenter::truncatedText(m_textItem->font(), m_label, qreal(0.0),
-                                                      width - x, rect.height(), truncatedRect));
     m_textItem->setTextWidth(truncatedRect.width());
 
     qreal y = qMax(m_markerRect.height() + 2 * m_margin, truncatedRect.height() + 2 * m_margin);
@@ -195,6 +200,15 @@ void LegendMarkerItem::hoverLeaveEvent(QGraphicsSceneHoverEvent *event)
     emit m_marker->q_ptr->hovered(false);
 }
 
+QString LegendMarkerItem::displayedLabel() const
+{
+    return m_textItem->toHtml();
+}
+
+void LegendMarkerItem::setToolTip(const QString &tip)
+{
+    m_textItem->setToolTip(tip);
+}
 
 #include "moc_legendmarkeritem_p.cpp"
 
diff --git a/src/charts/legend/legendmarkeritem_p.h b/src/charts/legend/legendmarkeritem_p.h
index 4b33ae39..870cfb2e 100644
--- a/src/charts/legend/legendmarkeritem_p.h
+++ b/src/charts/legend/legendmarkeritem_p.h
@@ -83,6 +83,8 @@ public:
     void hoverEnterEvent(QGraphicsSceneHoverEvent *event);
     void hoverLeaveEvent(QGraphicsSceneHoverEvent *event);
 
+    QString displayedLabel() const;
+    void setToolTip(const QString &tooltip);
 protected:
     QLegendMarkerPrivate *m_marker; // Knows
     QRectF m_markerRect;
diff --git a/src/charts/legend/qlegend.cpp b/src/charts/legend/qlegend.cpp
index 975de95f..4f75747c 100644
--- a/src/charts/legend/qlegend.cpp
+++ b/src/charts/legend/qlegend.cpp
@@ -164,6 +164,19 @@ QT_CHARTS_BEGIN_NAMESPACE
 */
 
 /*!
+    \property QLegend::showToolTips
+    Whether tooltips are shown when the text is truncated. This is false by default.
+
+    This will not have any effect when used in QML.
+*/
+
+/*!
+    \qmlproperty bool Legend::showToolTips
+    Whether tooltips are shown when the text is truncated. This is false by default.
+    This currently has no effect as there is no support for tooltips in QML.
+*/
+
+/*!
     \fn void QLegend::backgroundVisibleChanged(bool)
     The visibility of the legend background changed to \a visible.
 */
@@ -193,6 +206,11 @@ QT_CHARTS_BEGIN_NAMESPACE
     The use of reverse order for the markers in legend is changed to \a reverseMarkers.
 */
 
+/*!
+    \fn void QLegend::showToolTipsChanged(bool showToolTips)
+    This signal is emitted when the visibility of tooltips is changed to \a showToolTips.
+*/
+
 QLegend::QLegend(QChart *chart): QGraphicsWidget(chart),
     d_ptr(new QLegendPrivate(chart->d_ptr->m_presenter, chart, this))
 {
@@ -455,6 +473,31 @@ void QLegend::setReverseMarkers(bool reverseMarkers)
 }
 
 /*!
+    Returns whether the tooltips are shown or not for the legend labels
+    when they are elided.
+*/
+
+bool QLegend::showToolTips() const
+{
+    return d_ptr->m_showToolTips;
+}
+
+/*!
+    When \a show is true, the legend labels will show a tooltip when
+    the mouse hovers over them if the label itself is shown elided.
+    This is false by default.
+*/
+
+void QLegend::setShowToolTips(bool show)
+{
+    if (d_ptr->m_showToolTips != show) {
+        d_ptr->m_showToolTips = show;
+        d_ptr->updateToolTips();
+        emit showToolTipsChanged(show);
+    }
+}
+
+/*!
  \internal \a event see QGraphicsWidget for details
  */
 void QLegend::hideEvent(QHideEvent *event)
@@ -489,7 +532,8 @@ QLegendPrivate::QLegendPrivate(ChartPresenter *presenter, QChart *chart, QLegend
       m_diameter(5),
       m_attachedToChart(true),
       m_backgroundVisible(false),
-      m_reverseMarkers(false)
+      m_reverseMarkers(false),
+      m_showToolTips(false)
 {
     m_items->setHandlesChildEvents(false);
 }
@@ -651,7 +695,15 @@ void QLegendPrivate::decorateMarkers(QList<QLegendMarker *> markers)
     }
 }
 
-
+void QLegendPrivate::updateToolTips()
+{
+    foreach (QLegendMarker *m, m_markers) {
+        if (m->d_ptr->m_item->displayedLabel() != m->label())
+            m->d_ptr->m_item->setToolTip(m->label());
+        else
+            m->d_ptr->m_item->setToolTip(QString());
+    }
+}
 #include "moc_qlegend.cpp"
 #include "moc_qlegend_p.cpp"
 
diff --git a/src/charts/legend/qlegend.h b/src/charts/legend/qlegend.h
index 7de215df..8825af4d 100644
--- a/src/charts/legend/qlegend.h
+++ b/src/charts/legend/qlegend.h
@@ -52,6 +52,7 @@ class QT_CHARTS_EXPORT QLegend : public QGraphicsWidget
     Q_PROPERTY(QFont font READ font WRITE setFont NOTIFY fontChanged)
     Q_PROPERTY(QColor labelColor READ labelColor WRITE setLabelColor NOTIFY labelColorChanged)
     Q_PROPERTY(bool reverseMarkers READ reverseMarkers WRITE setReverseMarkers NOTIFY reverseMarkersChanged)
+    Q_PROPERTY(bool showToolTips READ showToolTips WRITE setShowToolTips NOTIFY showToolTipsChanged)
 
 private:
     explicit QLegend(QChart *chart);
@@ -94,6 +95,8 @@ public:
     bool reverseMarkers();
     void setReverseMarkers(bool reverseMarkers = true);
 
+    bool showToolTips() const;
+    void setShowToolTips(bool show);
 protected:
     void hideEvent(QHideEvent *event);
     void showEvent(QShowEvent *event);
@@ -105,6 +108,7 @@ Q_SIGNALS:
     void fontChanged(QFont font);
     void labelColorChanged(QColor color);
     void reverseMarkersChanged(bool reverseMarkers);
+    void showToolTipsChanged(bool showToolTips);
 
 private:
     QScopedPointer<QLegendPrivate> d_ptr;
diff --git a/src/charts/legend/qlegend_p.h b/src/charts/legend/qlegend_p.h
index f32116f1..7806015e 100644
--- a/src/charts/legend/qlegend_p.h
+++ b/src/charts/legend/qlegend_p.h
@@ -75,6 +75,7 @@ private:
     void addMarkers(QList<QLegendMarker *> markers);
     void removeMarkers(QList<QLegendMarker *> markers);
     void decorateMarkers(QList<QLegendMarker *> markers);
+    void updateToolTips();
 
 private:
     QLegend *q_ptr;
@@ -92,6 +93,7 @@ private:
     bool m_attachedToChart;
     bool m_backgroundVisible;
     bool m_reverseMarkers;
+    bool m_showToolTips;
 
     QList<QLegendMarker *> m_markers;
     QList<QAbstractSeries *> m_series;