Optimize single item changes in bar/surface item models.

We are only able to optimize this in cases where rows and
columns of the model are directly mapped to rows and columns
of the data proxy. In other cases we do not know if the new
values of the changed data item in the model actually specify the
same row/column in our data proxy as the previous values.

Task-number: QTRD-2190
Change-Id: Ie014469ac894474900e5cfd6d91fd1a60353b1f7
Reviewed-by: Titta Heikkala <titta.heikkala@digia.com>

1 files changed, 40 insertions, 10 deletions

diff --git a/src/datavisualization/data/baritemmodelhandler.cpp b/src/datavisualization/data/baritemmodelhandler.cpp
index 4f44fe1d..3b02c1e3 100644
--- a/src/datavisualization/data/baritemmodelhandler.cpp
+++ b/src/datavisualization/data/baritemmodelhandler.cpp
@@ -26,7 +26,9 @@ BarItemModelHandler::BarItemModelHandler(QItemModelBarDataProxy *proxy, QObject
     : AbstractItemModelHandler(parent),
       m_proxy(proxy),
       m_proxyArray(0),
-      m_columnCount(0)
+      m_columnCount(0),
+      m_valueRole(noRoleIndex),
+      m_rotationRole(noRoleIndex)
 {
 }
 
@@ -34,6 +36,34 @@ BarItemModelHandler::~BarItemModelHandler()
 {
 }
 
+void BarItemModelHandler::handleDataChanged(const QModelIndex &topLeft,
+                                            const QModelIndex &bottomRight,
+                                            const QVector<int> &roles)
+{
+    // Do nothing if full reset already pending
+    if (!m_fullReset) {
+        if (!m_proxy->useModelCategories()) {
+            // If the data model doesn't directly map rows and columns, we cannot optimize
+            AbstractItemModelHandler::handleDataChanged(topLeft, bottomRight, roles);
+        } else {
+            int startRow = qMin(topLeft.row(), bottomRight.row());
+            int endRow = qMax(topLeft.row(), bottomRight.row());
+            int startCol = qMin(topLeft.column(), bottomRight.column());
+            int endCol = qMax(topLeft.column(), bottomRight.column());
+
+            for (int i = startRow; i <= endRow; i++) {
+                for (int j = startCol; j <= endCol; j++) {
+                    QBarDataItem item;
+                    item.setValue(m_itemModel->index(i, j).data(m_valueRole).toFloat());
+                    if (m_rotationRole != noRoleIndex)
+                        item.setRotation(m_itemModel->index(i, j).data(m_rotationRole).toFloat());
+                    m_proxy->setItem(i, j, item);
+                }
+            }
+        }
+    }
+}
+
 // Resolve entire item model into QBarDataArray.
 void BarItemModelHandler::resolveModel()
 {
@@ -54,8 +84,8 @@ void BarItemModelHandler::resolveModel()
     QHash<int, QByteArray> roleHash = m_itemModel->roleNames();
 
     // Default value role to display role if no mapping
-    int valueRole = roleHash.key(m_proxy->valueRole().toLatin1(), Qt::DisplayRole);
-    int rotationRole = roleHash.key(m_proxy->rotationRole().toLatin1(), noRoleIndex);
+    m_valueRole = roleHash.key(m_proxy->valueRole().toLatin1(), Qt::DisplayRole);
+    m_rotationRole = roleHash.key(m_proxy->rotationRole().toLatin1(), noRoleIndex);
     int rowCount = m_itemModel->rowCount();
     int columnCount = m_itemModel->columnCount();
 
@@ -71,9 +101,9 @@ void BarItemModelHandler::resolveModel()
         for (int i = 0; i < rowCount; i++) {
             QBarDataRow &newProxyRow = *m_proxyArray->at(i);
             for (int j = 0; j < columnCount; j++) {
-                newProxyRow[j].setValue(m_itemModel->index(i, j).data(valueRole).toReal());
-                if (rotationRole != noRoleIndex)
-                    newProxyRow[j].setRotation(m_itemModel->index(i, j).data(rotationRole).toReal());
+                newProxyRow[j].setValue(m_itemModel->index(i, j).data(m_valueRole).toFloat());
+                if (m_rotationRole != noRoleIndex)
+                    newProxyRow[j].setRotation(m_itemModel->index(i, j).data(m_rotationRole).toFloat());
             }
         }
         // Generate labels from headers if using model rows/columns
@@ -104,9 +134,9 @@ void BarItemModelHandler::resolveModel()
                 QModelIndex index = m_itemModel->index(i, j);
                 QString rowRoleStr = index.data(rowRole).toString();
                 QString columnRoleStr = index.data(columnRole).toString();
-                itemValueMap[rowRoleStr][columnRoleStr] = index.data(valueRole).toReal();
-                if (rotationRole != noRoleIndex)
-                    itemRotationMap[rowRoleStr][columnRoleStr] = index.data(rotationRole).toReal();
+                itemValueMap[rowRoleStr][columnRoleStr] = index.data(m_valueRole).toFloat();
+                if (m_rotationRole != noRoleIndex)
+                    itemRotationMap[rowRoleStr][columnRoleStr] = index.data(m_rotationRole).toFloat();
                 if (generateRows && !rowListHash.value(rowRoleStr, false)) {
                     rowListHash.insert(rowRoleStr, true);
                     rowList << rowRoleStr;
@@ -142,7 +172,7 @@ void BarItemModelHandler::resolveModel()
             QBarDataRow &newProxyRow = *m_proxyArray->at(i);
             for (int j = 0; j < columnList.size(); j++) {
                 newProxyRow[j].setValue(itemValueMap[rowKey][columnList.at(j)]);
-                if (rotationRole != noRoleIndex)
+                if (m_rotationRole != noRoleIndex)
                     newProxyRow[j].setRotation(itemRotationMap[rowKey][columnList.at(j)]);
             }
         }