Enable querying selection label via API

Also enable suppressing drawing the label on graph.

Selection label formatting was consequently moved from renderers
to series.

Task-number: QTRD-2896

Change-Id: Ia6a1a40298d8db0f54349de3eb27fb0b683dd302
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>

5 files changed, 17 insertions, 56 deletions

diff --git a/examples/datavisualization/qmlaxisformatter/customformatter.cpp b/examples/datavisualization/qmlaxisformatter/customformatter.cpp
index eeea0451..4a52d273 100644
--- a/examples/datavisualization/qmlaxisformatter/customformatter.cpp
+++ b/examples/datavisualization/qmlaxisformatter/customformatter.cpp
@@ -142,6 +142,7 @@ void CustomFormatter::setSelectionFormat(const QString &format)
 {
     if (m_selectionFormat != format) {
         m_selectionFormat = format;
+        markDirty(true); // Necessary to regenerate already visible selection label
         emit selectionFormatChanged(format);
     }
 }
diff --git a/examples/datavisualization/qmloscilloscope/datasource.cpp b/examples/datavisualization/qmloscilloscope/datasource.cpp
index 01d7e73d..40ebd962 100644
--- a/examples/datavisualization/qmloscilloscope/datasource.cpp
+++ b/examples/datavisualization/qmloscilloscope/datasource.cpp
@@ -138,29 +138,6 @@ void DataSource::update(QSurface3DSeries *series)
 }
 //! [1]
 
-//! [2]
-QString DataSource::selectionLabel(QSurface3DSeries *series, QValue3DAxis *axisX,
-                                   QValue3DAxis *axisY, QValue3DAxis *axisZ)
-{
-    QString label;
-
-    if (series && series->selectedPoint() != QSurface3DSeries::invalidSelectionPosition()) {
-        const QSurfaceDataItem *item = series->dataProxy()->itemAt(series->selectedPoint());
-        QString x;
-        QString y;
-        QString z;
-        x.sprintf(axisX->labelFormat().toUtf8().constData(), int(item->x()));
-        y.sprintf(axisY->labelFormat().toUtf8().constData(), int(item->y()));
-        z.sprintf(axisZ->labelFormat().toUtf8().constData(), int(item->z()));
-        label = QStringLiteral("%1, %3: %2").arg(x).arg(y).arg(z);
-    } else {
-        label = QStringLiteral("No selection");
-    }
-
-    return label;
-}
-//! [2]
-
 void DataSource::clearData()
 {
     for (int i(0); i < m_data.size(); i++) {
diff --git a/examples/datavisualization/qmloscilloscope/datasource.h b/examples/datavisualization/qmloscilloscope/datasource.h
index 4f210269..76ba7c9c 100644
--- a/examples/datavisualization/qmloscilloscope/datasource.h
+++ b/examples/datavisualization/qmloscilloscope/datasource.h
@@ -37,9 +37,6 @@ public slots:
                       float xMin, float xMax, float yMin, float yMax, float zMin, float zMax);
 
     void update(QSurface3DSeries *series);
-
-    QString selectionLabel(QSurface3DSeries *series, QValue3DAxis *axisX,
-                           QValue3DAxis *axisY, QValue3DAxis *axisZ);
     //! [0]
 private:
     void clearData();
diff --git a/examples/datavisualization/qmloscilloscope/doc/src/qmloscilloscope.qdoc b/examples/datavisualization/qmloscilloscope/doc/src/qmloscilloscope.qdoc
index c574950b..93bd5c30 100644
--- a/examples/datavisualization/qmloscilloscope/doc/src/qmloscilloscope.qdoc
+++ b/examples/datavisualization/qmloscilloscope/doc/src/qmloscilloscope.qdoc
@@ -59,11 +59,6 @@
     we still need to call QSurfaceDataProxy::resetArray() after changing the data in it to prompt
     the graph to render the data.
 
-    The final method, \c selectionLabel(), is used to generate a label string we can show on the
-    QML ui. This method utilizes the axis formats to format the label:
-
-    \snippet qmloscilloscope/datasource.cpp 2
-
     To be able to access the \c DataSource methods from QML, we need to expose it. We do this by
     defining a context property in application main:
 
@@ -86,15 +81,11 @@
     One interesting detail is that we don't specify a proxy for the Surface3DSeries we attach
     to the graph. This makes the series to utilize the default QSurfaceDataProxy.
 
-    We also specify an empty string for \l{Abstract3DSeries::itemLabelFormat}{itemLabelFormat}, since we want to display
-    the selected item information in a \c Text element instead of a label above the selection pointer.
+    We also hide the item label with \l{Abstract3DSeries::itemLabelVisible}{itemLabelFormat}, since
+    we want to display the selected item information in a \c Text element instead of a floating
+    label above the selection pointer.
     This is done because the selection pointer moves around a lot as the data changes, which makes
     the regular selection label difficult to read.
-    When selection point changes, we update the label text using a helper function
-    \c updateSelectionLabel(), which calls one of the methods we defined for our \c DataSource class
-    to obtain the label:
-
-    \snippet qmloscilloscope/qml/qmloscilloscope/main.qml 1
 
     We initialize the \c DataSource cache when the graph is complete by calling a helper function
     \c generateData(), which calls the method with the same name on the \c DataSource:
diff --git a/examples/datavisualization/qmloscilloscope/qml/qmloscilloscope/main.qml b/examples/datavisualization/qmloscilloscope/qml/qmloscilloscope/main.qml
index 81884154..5f5bfe1a 100644
--- a/examples/datavisualization/qmloscilloscope/qml/qmloscilloscope/main.qml
+++ b/examples/datavisualization/qmloscilloscope/qml/qmloscilloscope/main.qml
@@ -19,7 +19,7 @@
 import QtQuick 2.1
 import QtQuick.Layouts 1.0
 import QtQuick.Controls 1.0
-import QtDataVisualization 1.0
+import QtDataVisualization 1.1
 import "."
 
 Item {
@@ -72,9 +72,8 @@ Item {
                 drawMode: Surface3DSeries.DrawSurface;
                 flatShadingEnabled: false;
                 meshSmooth: true
-                itemLabelFormat: ""
-
-                onSelectedPointChanged: mainView.updateSelectionLabel()
+                itemLabelFormat: "@xLabel, @zLabel: @yLabel"
+                itemLabelVisible: false
             }
             //! [0]
 
@@ -90,10 +89,7 @@ Item {
         interval: 1000 / frequencySlider.value
         running: true
         repeat: true
-        onTriggered: {
-            dataSource.update(surfaceSeries)
-            mainView.updateSelectionLabel()
-        }
+        onTriggered: dataSource.update(surfaceSeries)
     }
     //! [3]
 
@@ -218,10 +214,18 @@ Item {
 
                     Text {
                         id: selectionText
-                        text: "No selection"
                         anchors.fill: parent
                         verticalAlignment: Text.AlignVCenter
                         horizontalAlignment: Text.AlignHCenter
+
+                        Binding on text {
+                            when: surfaceSeries.itemLabel.length
+                            value: surfaceSeries.itemLabel
+                        }
+                        Binding on text {
+                            when: !surfaceSeries.itemLabel.length
+                            value: "No selection"
+                        }
                     }
                 }
             }
@@ -285,15 +289,6 @@ Item {
 
     }
 
-    //! [1]
-    function updateSelectionLabel() {
-        selectionText.text = dataSource.selectionLabel(surfaceSeries,
-                                                       surfaceGraph.axisX,
-                                                       surfaceGraph.axisY,
-                                                       surfaceGraph.axisZ)
-    }
-    //! [1]
-
     //! [4]
     function generateData() {
         dataSource.generateData(mainView.sampleCache, mainView.sampleRows,