1 files changed, 100 insertions, 0 deletions
diff --git a/examples/datavisualization/graphgallery/variantbardataproxy.py b/examples/datavisualization/graphgallery/variantbardataproxy.py
new file mode 100644
index 000000000..f69ebaf80
--- /dev/null
+++ b/examples/datavisualization/graphgallery/variantbardataproxy.py
@@ -0,0 +1,100 @@
+# Copyright (C) 2023 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+from PySide6.QtCore import Slot
+from PySide6.QtDataVisualization import QBarDataProxy, QBarDataItem
+
+
+class VariantBarDataProxy(QBarDataProxy):
+
+    def __init__(self):
+        super().__init__()
+        self._dataSet = None
+        self._mapping = None
+
+    def setDataSet(self, newSet):
+        if self._dataSet:
+            self._dataSet.itemsAdded.disconnect(self.handleItemsAdded)
+            self._dataSet.dataCleared.disconnect(self.handleDataCleared)
+
+        self._dataSet = newSet
+
+        if self._dataSet:
+            self._dataSet.itemsAdded.connect(self.handleItemsAdded)
+            self._dataSet.dataCleared.connect(self.handleDataCleared)
+        self.resolveDataSet()
+
+    def dataSet(self):
+        return self._dataSet.data()
+
+    # Map key (row, column, value) to value index in data item (VariantItem).
+    # Doesn't gain ownership of mapping, but does connect to it to listen for
+    # mapping changes. Modifying mapping that is set to proxy will trigger
+    # dataset re-resolving.
+    def setMapping(self, mapping):
+        if self._mapping:
+            self._mapping.mappingChanged.disconnect(self.handleMappingChanged)
+
+        self._mapping = mapping
+
+        if self._mapping:
+            self._mapping.mappingChanged.connect(self.handleMappingChanged)
+
+        self.resolveDataSet()
+
+    def mapping(self):
+        return self._mapping.data()
+
+    @Slot(int, int)
+    def handleItemsAdded(self, index, count):
+        # Resolve new items
+        self.resolveDataSet()
+
+    @Slot()
+    def handleDataCleared(self):
+        # Data cleared, reset array
+        self.resetArray(None)
+
+    @Slot()
+    def handleMappingChanged(self):
+        self.resolveDataSet()
+
+    # Resolve entire dataset into QBarDataArray.
+    def resolveDataSet(self):
+        # If we have no data or mapping, or the categories are not defined,
+        # simply clear the array
+        if (not self._dataSet or not self._mapping
+                or not self._mapping.rowCategories()
+                or not self._mapping.columnCategories()):
+            self.resetArray()
+            return
+
+        itemList = self._dataSet.itemList()
+
+        rowIndex = self._mapping.rowIndex()
+        columnIndex = self._mapping.columnIndex()
+        valueIndex = self._mapping.valueIndex()
+        rowList = self._mapping.rowCategories()
+        columnList = self._mapping.columnCategories()
+
+        # Sort values into rows and columns
+        itemValueMap = {}
+        for item in itemList:
+            key = str(item[rowIndex])
+            v = itemValueMap.get(key)
+            if not v:
+                v = {}
+                itemValueMap[key] = v
+            v[str(item[columnIndex])] = float(item[valueIndex])
+
+        # Create a new data array in format the parent class understands
+        newProxyArray = []
+        for rowKey in rowList:
+            newProxyRow = []
+            for i in range(0, len(columnList)):
+                item = QBarDataItem(itemValueMap[rowKey][columnList[i]])
+                newProxyRow.append(item)
+            newProxyArray.append(newProxyRow)
+
+        # Finally, reset the data array in the parent class
+        self.resetArray(newProxyArray)