Further improved the charts example

examples/charts/main.qml

@@ -1,5 +1,7 @@
 import QtQuick 2.7
 import QtCharts 2.2
+import QtQuick.Controls 2.2
+import QtQuick.Layouts 1.3
 import QtQuick.Window 2.3
 
 Window {
@@ -9,22 +11,44 @@ Window {
 
     Component.onCompleted: visible = true
 
-    ChartView {
-        id: view
+    ColumnLayout {
+	anchors.fill: parent
 
-        anchors.fill: parent
+	ChartView {
+            id: view
 
-        VXYModelMapper {
-            id: mapper
-            model: myListModel
-            series: lineSeries
-            xColumn: 0
-            yColumn: 1
-        }
+	    Layout.fillHeight: true
+	    Layout.fillWidth: true
 
-        LineSeries {
-            id: lineSeries
-            name: "LineSeries"
-        }
+            VXYModelMapper {
+		id: mapper
+		model: myListModel
+		series: lineSeries
+		xColumn: 0
+		yColumn: 1
+            }
+
+            LineSeries {
+		id: lineSeries
+		name: "LineSeries"
+		axisX: ValueAxis {
+		    min: 0
+		    max: myListModel.maxX
+		}
+		axisY: ValueAxis {
+		    min: 0
+		    max: myListModel.maxY
+		}
+            }
+	}
+
+	RowLayout {
+	    Layout.fillWidth: true
+
+	    Button {
+		text: "Add random point"
+		onClicked: myListModel.addRandomPoint()
+	    }
+	}
     }
 }

examples/charts/mylistmodel.nim

@@ -1,4 +1,4 @@
-import NimQml, Tables
+import NimQml, Tables, random
 
 type
   Point = object
@@ -9,6 +9,8 @@ QtObject:
   type
     MyListModel* = ref object of QAbstractListModel
       points*: seq[Point]
+      maxX: int
+      maxY: int
 
   proc delete(self: MyListModel) =
     self.QAbstractListModel.delete
@@ -16,33 +18,60 @@ QtObject:
   proc setup(self: MyListModel) =
     self.QAbstractListModel.setup
 
-  proc newMyListModel*(): MyListModel =
-    new(result, delete)
-    result.points = @[Point(x: 10, y: 20), Point(x: 20, y: 30)]
-    result.setup
-
   method rowCount(self: MyListModel, index: QModelIndex = nil): int =
-    if index == nil or not index.isValid:
-      return self.points.len
-    return 0
+    return self.points.len
 
   method columnCount(self: MyListModel, index: QModelIndex = nil): int =
-    if index == nil or not index.isValid:
-      return 2
-    return 0
+    return 2
 
   method data(self: MyListModel, index: QModelIndex, role: int): QVariant =
     result = nil
     if not index.isValid:
       return 
-    if index.row < 0 or index.row >= self.points.len:
-      return
-    if index.column < 0 or index.column >= 2:
-      return
-    let point = self.points[index.row]
-    if index.column == 0:
-      return newQVariant(point.x)
-    elif index.column == 1:
-      return newQVariant(point.y)
-    else:
-      return
+    if role == 0:
+      let point = self.points[index.row]
+      if index.column == 0:
+        return newQVariant(point.x)
+      elif index.column == 1:
+        return newQVariant(point.y)
+
+  proc getMaxY(self: MyListModel): int {.slot.} =
+    return self.maxY
+
+  proc maxYChanged(self: MyListModel, value: int) {.signal.}
+
+  QtProperty[int] maxY:
+    read = getMaxY
+    notify = maxYChanged
+
+  proc getMaxX(self: MyListModel): int {.slot.} =
+    return self.maxX
+
+  proc maxXChanged(self: MyListModel, value: int) {.signal.}
+
+  QtProperty[int] maxX:
+    read = getMaxX
+    notify = maxXChanged
+
+  proc addRandomPoint(self: MyListModel) {.slot.} =
+    let pos = self.points.len
+    self.beginInsertRows(newQModelIndex(), pos, pos)
+    let x = self.maxX + 1
+    let y = random(50)
+    if x > self.maxX:
+      self.maxX = x
+      self.maxXChanged(x)
+    if y > self.maxY:
+      self.maxY = y
+      self.maxYChanged(y)
+    echo "Adding " & $x & " " & $y
+    self.points.add(Point(x: x, y: y))
+    self.endInsertRows()
+
+  proc newMyListModel*(): MyListModel =
+    new(result, delete)
+    result.setup
+    result.points = @[]
+    result.maxX = 0
+    result.maxY = 50
+    result.addRandomPoint()