Move series updates to C++

Instead of jumping to and from the QML engine for each sensor update,
rather stay inside C++ and let QML only do the visual updates.

This only updates the items which use Charts, as updates to a series is
expensive.

Change-Id: Idc7a98d2865e7095264f226c0ac5bbb5a977d18a
Reviewed-by: Titta Heikkala <titta.heikkala@qt.io>

1 files changed, 6 insertions, 19 deletions

diff --git a/tradeshow/iot-sensortag/resources/base/GyroChart.qml b/tradeshow/iot-sensortag/resources/base/GyroChart.qml
index 30aba64..f7d2b71 100644
--- a/tradeshow/iot-sensortag/resources/base/GyroChart.qml
+++ b/tradeshow/iot-sensortag/resources/base/GyroChart.qml
@@ -51,12 +51,12 @@ import QtQuick 2.5
 import QtCharts 2.1
 import SensorTag.DataProvider 1.0
 import QtGraphicalEffects 1.0
+import QtQml 2.2
 
 BaseChart {
     id: gyroHolderRect
 
     // Replace with actual gyro properties
-    property int gyroSeriesIndex: 0
     property int maxGyroReadings: 24
 
     readonly property string xColor: "#15bdff"
@@ -64,12 +64,6 @@ BaseChart {
     readonly property string zColor: "red"
     readonly property color textColor: "white"
 
-    onSensorChanged: {
-            if (sensor) {
-                sensor.rotationValuesChanged.connect(contentItem.updateRotation);
-            }
-    }
-
     onClicked: {
         if (sensor)
             sensor.recalibrate();
@@ -81,19 +75,12 @@ BaseChart {
     content: Item {
         anchors.fill: parent
 
-        function updateRotation() {
-            gyroSeriesX.append(gyroSeriesIndex, sensor.rotationX);
-            gyroSeriesY.append(gyroSeriesIndex, sensor.rotationY);
-            gyroSeriesZ.append(gyroSeriesIndex, sensor.rotationZ);
-
-            if (gyroSeriesIndex >= maxGyroReadings) {
-                gyroSeriesX.remove(gyroSeriesX.at(gyroSeriesIndex-maxGyroReadings));
-                gyroSeriesY.remove(gyroSeriesY.at(gyroSeriesIndex-maxGyroReadings));
-                gyroSeriesZ.remove(gyroSeriesZ.at(gyroSeriesIndex-maxGyroReadings));
-                valueAxisX.min++;
-                valueAxisX.max++;
+        Connections {
+            target: mainWindow
+            onSeriesStorageChanged: {
+                if (seriesStorage)
+                    seriesStorage.setGyroSeries(gyroSeriesX, gyroSeriesY, gyroSeriesZ);
             }
-            gyroSeriesIndex++;
         }
 
         Glow {