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, 60 insertions, 18 deletions

diff --git a/src/datavisualization/data/surfaceitemmodelhandler.cpp b/src/datavisualization/data/surfaceitemmodelhandler.cpp
index f4383dbf..584ddf28 100644
--- a/src/datavisualization/data/surfaceitemmodelhandler.cpp
+++ b/src/datavisualization/data/surfaceitemmodelhandler.cpp
@@ -25,7 +25,10 @@ static const int noRoleIndex = -1;
 SurfaceItemModelHandler::SurfaceItemModelHandler(QItemModelSurfaceDataProxy *proxy, QObject *parent)
     : AbstractItemModelHandler(parent),
       m_proxy(proxy),
-      m_proxyArray(0)
+      m_proxyArray(0),
+      m_xPosRole(noRoleIndex),
+      m_yPosRole(noRoleIndex),
+      m_zPosRole(noRoleIndex)
 {
 }
 
@@ -33,6 +36,45 @@ SurfaceItemModelHandler::~SurfaceItemModelHandler()
 {
 }
 
+void SurfaceItemModelHandler::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++) {
+                    QSurfaceDataItem item;
+                    const QSurfaceDataItem *oldItem = m_proxy->itemAt(i, j);
+                    float xPos;
+                    float zPos;
+                    if (m_xPosRole != noRoleIndex)
+                        xPos = m_itemModel->index(i, j).data(m_xPosRole).toFloat();
+                    else
+                        xPos = oldItem->x();
+                    if (m_zPosRole != noRoleIndex)
+                        zPos = m_itemModel->index(i, j).data(m_zPosRole).toFloat();
+                    else
+                        zPos = oldItem->z();
+                    item.setPosition(QVector3D(xPos,
+                                               m_itemModel->index(i, j).data(m_yPosRole).toFloat(),
+                                               zPos));
+                    m_proxy->setItem(i, j, item);
+                }
+            }
+        }
+    }
+}
+
 // Resolve entire item model into QSurfaceDataArray.
 void SurfaceItemModelHandler::resolveModel()
 {
@@ -52,9 +94,9 @@ void SurfaceItemModelHandler::resolveModel()
     QHash<int, QByteArray> roleHash = m_itemModel->roleNames();
 
     // Default to display role if no mapping
-    int xPosRole = roleHash.key(m_proxy->xPosRole().toLatin1(), noRoleIndex);
-    int yPosRole = roleHash.key(m_proxy->yPosRole().toLatin1(), Qt::DisplayRole);
-    int zPosRole = roleHash.key(m_proxy->zPosRole().toLatin1(), noRoleIndex);
+    m_xPosRole = roleHash.key(m_proxy->xPosRole().toLatin1(), noRoleIndex);
+    m_yPosRole = roleHash.key(m_proxy->yPosRole().toLatin1(), Qt::DisplayRole);
+    m_zPosRole = roleHash.key(m_proxy->zPosRole().toLatin1(), noRoleIndex);
     int rowCount = m_itemModel->rowCount();
     int columnCount = m_itemModel->columnCount();
 
@@ -70,10 +112,10 @@ void SurfaceItemModelHandler::resolveModel()
         for (int i = 0; i < rowCount; i++) {
             QSurfaceDataRow &newProxyRow = *m_proxyArray->at(i);
             for (int j = 0; j < columnCount; j++) {
-                float xPos = j;
-                float zPos = i;
-                if (xPosRole != noRoleIndex) {
-                    xPos = m_itemModel->index(i, j).data(xPosRole).toFloat();
+                float xPos = float(j);
+                float zPos = float(i);
+                if (m_xPosRole != noRoleIndex) {
+                    xPos = m_itemModel->index(i, j).data(m_xPosRole).toFloat();
                 } else {
                     QString header = m_itemModel->headerData(j, Qt::Horizontal).toString();
                     bool ok = false;
@@ -82,8 +124,8 @@ void SurfaceItemModelHandler::resolveModel()
                         xPos = headerValue;
                 }
 
-                if (zPosRole != noRoleIndex) {
-                    zPos = m_itemModel->index(i, j).data(zPosRole).toFloat();
+                if (m_zPosRole != noRoleIndex) {
+                    zPos = m_itemModel->index(i, j).data(m_zPosRole).toFloat();
                 } else {
                     QString header = m_itemModel->headerData(i, Qt::Vertical).toString();
                     bool ok = false;
@@ -94,17 +136,17 @@ void SurfaceItemModelHandler::resolveModel()
 
                 newProxyRow[j].setPosition(
                             QVector3D(xPos,
-                                      m_itemModel->index(i, j).data(yPosRole).toFloat(),
+                                      m_itemModel->index(i, j).data(m_yPosRole).toFloat(),
                                       zPos));
             }
         }
     } else {
         int rowRole = roleHash.key(m_proxy->rowRole().toLatin1());
         int columnRole = roleHash.key(m_proxy->columnRole().toLatin1());
-        if (xPosRole == noRoleIndex)
-            xPosRole = columnRole;
-        if (zPosRole == noRoleIndex)
-            zPosRole = rowRole;
+        if (m_xPosRole == noRoleIndex)
+            m_xPosRole = columnRole;
+        if (m_zPosRole == noRoleIndex)
+            m_zPosRole = rowRole;
 
         bool generateRows = m_proxy->autoRowCategories();
         bool generateColumns = m_proxy->autoColumnCategories();
@@ -124,9 +166,9 @@ void SurfaceItemModelHandler::resolveModel()
                 QModelIndex index = m_itemModel->index(i, j);
                 QString rowRoleStr = index.data(rowRole).toString();
                 QString columnRoleStr = index.data(columnRole).toString();
-                QVector3D itemPos(index.data(xPosRole).toReal(),
-                                  index.data(yPosRole).toReal(),
-                                  index.data(zPosRole).toReal());
+                QVector3D itemPos(index.data(m_xPosRole).toFloat(),
+                                  index.data(m_yPosRole).toFloat(),
+                                  index.data(m_zPosRole).toFloat());
                 itemValueMap[rowRoleStr][columnRoleStr] = itemPos;
                 if (generateRows && !rowListHash.value(rowRoleStr, false)) {
                     rowListHash.insert(rowRoleStr, true);