- Qt 6.7
- Qt Graphs
- Graph Gallery
- Qt Graphs | Commercial or GPLv3

# Graph Gallery

     // Copyright (C) 2023 The Qt Company Ltd.
     // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

     #include "variantbardataproxy.h"

     VariantBarDataProxy::VariantBarDataProxy() = default;

     VariantBarDataProxy::~VariantBarDataProxy()
     {
         delete m_dataSet;
     }

     void VariantBarDataProxy::setDataSet(VariantDataSet *newSet)
     {
         if (!m_dataSet.isNull())
             QObject::disconnect(m_dataSet.data(), nullptr, this, nullptr);

         m_dataSet = newSet;

         if (!m_dataSet.isNull()) {
             QObject::connect(m_dataSet.data(),
                              &VariantDataSet::itemsAdded,
                              this,
                              &VariantBarDataProxy::handleItemsAdded);
             QObject::connect(m_dataSet.data(),
                              &VariantDataSet::dataCleared,
                              this,
                              &VariantBarDataProxy::handleDataCleared);
         }
         resolveDataSet();
     }

     VariantDataSet *VariantBarDataProxy::dataSet()
     {
         return m_dataSet.data();
     }

     void VariantBarDataProxy::setMapping(VariantBarDataMapping *mapping)
     {
         if (!m_mapping.isNull()) {
             QObject::disconnect(m_mapping.data(),
                                 &VariantBarDataMapping::mappingChanged,
                                 this,
                                 &VariantBarDataProxy::handleMappingChanged);
         }

         m_mapping = mapping;

         if (!m_mapping.isNull()) {
             QObject::connect(m_mapping.data(),
                              &VariantBarDataMapping::mappingChanged,
                              this,
                              &VariantBarDataProxy::handleMappingChanged);
         }

         resolveDataSet();
     }

     VariantBarDataMapping *VariantBarDataProxy::mapping()
     {
         return m_mapping.data();
     }

     void VariantBarDataProxy::handleItemsAdded(int index, int count)
     {
         Q_UNUSED(index);
         Q_UNUSED(count);

         // Resolve new items
         resolveDataSet();
     }

     void VariantBarDataProxy::handleDataCleared()
     {
         // Data cleared, reset array
         resetArray();
     }

     void VariantBarDataProxy::handleMappingChanged()
     {
         resolveDataSet();
     }

     // Resolve entire dataset into QBarDataArray.
     void VariantBarDataProxy::resolveDataSet()
     {
         // If we have no data or mapping, or the categories are not defined, simply
         // clear the array
         if (m_dataSet.isNull() || m_mapping.isNull() || !m_mapping->rowCategories().size()
             || !m_mapping->columnCategories().size()) {
             resetArray();
             return;
         }
         const VariantDataItemList &itemList = m_dataSet->itemList();

         int rowIndex = m_mapping->rowIndex();
         int columnIndex = m_mapping->columnIndex();
         int valueIndex = m_mapping->valueIndex();
         const QStringList &rowList = m_mapping->rowCategories();
         const QStringList &columnList = m_mapping->columnCategories();

         // Sort values into rows and columns
         using ColumnValueMap = QHash<QString, float>;
         QHash<QString, ColumnValueMap> itemValueMap;
         for (const VariantDataItem *item : itemList) {
             itemValueMap[item->at(rowIndex).toString()][item->at(columnIndex).toString()]
                 = item->at(valueIndex).toReal();
         }

         // Create a new data array in format the parent class understands
         QBarDataArray newProxyArray;
         for (const QString &rowKey : rowList) {
             QBarDataRow newProxyRow(columnList.size());
             for (qsizetype i = 0; i < columnList.size(); ++i)
                 newProxyRow[i].setValue(itemValueMap[rowKey][columnList.at(i)]);
             newProxyArray.append(newProxyRow);
         }

         // Finally, reset the data array in the parent class
         resetArray(newProxyArray);
     }