Allow resetting with existing array for surface

Improves performance when doing stuff like resetting image data.

Task-number: QTRD-2335
Change-Id: I9e8ce49fd520b67125305a7614afc550b2244169
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@digia.com>

5 files changed, 77 insertions, 52 deletions

diff --git a/src/datavisualization/data/qheightmapsurfacedataproxy.cpp b/src/datavisualization/data/qheightmapsurfacedataproxy.cpp
index 25e2a4db..c0b0723c 100644
--- a/src/datavisualization/data/qheightmapsurfacedataproxy.cpp
+++ b/src/datavisualization/data/qheightmapsurfacedataproxy.cpp
@@ -206,28 +206,35 @@ void QHeightMapSurfaceDataProxyPrivate::handlePendingResolve()
     int widthBits = imageWidth * 4;
     qreal height = 0;
 
-    QSurfaceDataArray *dataArray = new QSurfaceDataArray;
-    dataArray->reserve(imageHeight);
+    // Do not recreate array if dimensions have not changed
+    QSurfaceDataArray *dataArray = m_dataArray;
+    if (imageWidth != qptr()->columnCount() || imageHeight != dataArray->size()) {
+        dataArray = new QSurfaceDataArray;
+        dataArray->reserve(imageHeight);
+        for (int i = 0; i < imageHeight; i++) {
+            QSurfaceDataRow *newProxyRow = new QSurfaceDataRow(imageWidth);
+            dataArray->append(newProxyRow);
+        }
+    }
+
     if (heightImage.isGrayscale()) {
         // Grayscale, it's enough to read Red byte
-        for (int i = imageHeight; i > 0; i--, bitCount -= widthBits) {
-            QSurfaceDataRow *newRow = new QSurfaceDataRow(imageWidth);
+        for (int i = 0; i < imageHeight; i++, bitCount -= widthBits) {
+            QSurfaceDataRow &newRow = *dataArray->at(i);
             for (int j = 0; j < imageWidth; j++)
-                (*newRow)[j] = qreal(bits[bitCount + (j * 4)]);
-            *dataArray << newRow;
+                newRow[j] = qreal(bits[bitCount + (j * 4)]);
         }
     } else {
         // Not grayscale, we'll need to calculate height from RGB
-        for (int i = imageHeight; i > 0; i--, bitCount -= widthBits) {
-            QSurfaceDataRow *newRow = new QSurfaceDataRow(imageWidth);
+        for (int i = 0; i < imageHeight; i++, bitCount -= widthBits) {
+            QSurfaceDataRow &newRow = *dataArray->at(i);
             for (int j = 0; j < imageWidth; j++) {
                 int nextpixel = j * 4;
                 height = (qreal(bits[bitCount + nextpixel])
                         + qreal(bits[1 + bitCount + nextpixel])
                         + qreal(bits[2 + bitCount + nextpixel]));
-                (*newRow)[j] = (height / 3.0);
+                newRow[j] = height / 3.0;
             }
-            *dataArray << newRow;
         }
     }
 
diff --git a/src/datavisualization/data/qsurfacedataproxy.cpp b/src/datavisualization/data/qsurfacedataproxy.cpp
index 1a2e29ce..98998f10 100644
--- a/src/datavisualization/data/qsurfacedataproxy.cpp
+++ b/src/datavisualization/data/qsurfacedataproxy.cpp
@@ -143,23 +143,29 @@ QSurfaceDataProxy::~QSurfaceDataProxy()
 }
 
 /*!
- * Clears the existing array and takes ownership of the \a newArray. Do not use \a newArray pointer
- * to further modify data after QSurfaceDataProxy assumes ownership of it, as such modifications will
- * not trigger proper signals.
- * Passing null array clears all data.
- * Row and column ranges are reset to defaults.
+ * Takes ownership of the \a newArray. Clears the existing array and if the \a newArray is
+ * different than the existing array. If it's the same array, this just triggers arrayReset()
+ * signal.
+ * Passing null array deletes the old array and creates a new empty array.
+ * All rows in \a newArray must be of same length.
+ * Row and column ranges are reset to defaults, unless \a newArray is the same as the old array.
+ * In that case, old row and column ranges are kept.
  */
 void QSurfaceDataProxy::resetArray(QSurfaceDataArray *newArray)
 {
-    if (dptr()->resetArray(newArray, defaultMinValue, defaultMaxValue, defaultMinValue, defaultMaxValue))
-        emit arrayReset();
+    if (dptr()->m_dataArray != newArray) {
+        dptr()->resetArray(newArray, defaultMinValue, defaultMaxValue, defaultMinValue,
+                           defaultMaxValue);
+    }
+    emit arrayReset();
 }
 
 /*!
- * Clears the existing array and takes ownership of the \a newArray. Do not use \a newArray pointer
- * to further modify data after QSurfaceDataProxy assumes ownership of it, as such modifications will
- * not trigger proper signals.
- * Passing null array clears all data.
+ * Takes ownership of the \a newArray. Clears the existing array and if the \a newArray is
+ * different than the existing array. If it's the same array, this just triggers arrayReset()
+ * signal and updates row/column values.
+ * Passing null array deletes the old array and creates a new empty array.
+ * All rows in \a newArray must be of same length.
  * Row and column ranges are set to values defined by the rest of the parameters: \a minValueRows,
  * \a maxValueRows, \a minValueColumns, and \a maxValueColumns.
  */
@@ -167,8 +173,8 @@ void QSurfaceDataProxy::resetArray(QSurfaceDataArray *newArray, qreal minValueRo
                                    qreal maxValueRows, qreal minValueColumns,
                                    qreal maxValueColumns)
 {
-    if (dptr()->resetArray(newArray, minValueRows, maxValueRows, minValueColumns, maxValueColumns))
-        emit arrayReset();
+    dptr()->resetArray(newArray, minValueRows, maxValueRows, minValueColumns, maxValueColumns);
+    emit arrayReset();
 }
 
 /*!
@@ -346,30 +352,20 @@ QSurfaceDataProxyPrivate::~QSurfaceDataProxyPrivate()
     clearArray();
 }
 
-bool QSurfaceDataProxyPrivate::resetArray(QSurfaceDataArray *newArray, qreal minValueRows,
+void QSurfaceDataProxyPrivate::resetArray(QSurfaceDataArray *newArray, qreal minValueRows,
                                           qreal maxValueRows, qreal minValueColumns,
                                           qreal maxValueColumns)
 {
-    if (!m_dataArray->size() && (!newArray || !newArray->size()))
-        return false;
-
-    clearArray();
+    if (!newArray)
+        newArray = new QSurfaceDataArray;
 
-    if (newArray) {
-        for (int i = 0; i < newArray->size(); i++) {
-            Q_ASSERT_X((newArray->at(i) && newArray->at(i)->size() == newArray->at(0)->size()),
-                       __FUNCTION__,
-                       "All rows of QSurfaceDataArray mustn't be NULL and must be of equal size.");
-        }
+    if (newArray != m_dataArray) {
+        clearArray();
         m_dataArray = newArray;
-    } else {
-        m_dataArray = new QSurfaceDataArray;
     }
 
     setValueRangeRows(minValueRows, maxValueRows);
     setValueRangeColumns(minValueColumns, maxValueColumns);
-
-    return true;
 }
 
 void QSurfaceDataProxyPrivate::setValueRangeRows(qreal min, qreal max)
diff --git a/src/datavisualization/data/qsurfacedataproxy_p.h b/src/datavisualization/data/qsurfacedataproxy_p.h
index 8a60e93d..a40e8d65 100644
--- a/src/datavisualization/data/qsurfacedataproxy_p.h
+++ b/src/datavisualization/data/qsurfacedataproxy_p.h
@@ -43,7 +43,7 @@ public:
     QSurfaceDataProxyPrivate(QSurfaceDataProxy *q);
     virtual ~QSurfaceDataProxyPrivate();
 
-    bool resetArray(QSurfaceDataArray *newArray, qreal minValueRows, qreal maxValueRows,
+    void resetArray(QSurfaceDataArray *newArray, qreal minValueRows, qreal maxValueRows,
                     qreal minValueColumns, qreal maxValueColumns);
 
     void setValueRangeRows(qreal min, qreal max);
@@ -58,12 +58,14 @@ public:
 
     void limitValues(QVector3D &minValues, QVector3D &maxValues);
 
+protected:
+    QSurfaceDataArray *m_dataArray;
+
 private:
     QSurfaceDataProxy *qptr();
     void clearRow(int rowIndex);
     void clearArray();
 
-    QSurfaceDataArray *m_dataArray;
     qreal m_minValueRows;
     qreal m_maxValueRows;
     qreal m_minValueColumns;
diff --git a/src/datavisualization/data/surfaceitemmodelhandler.cpp b/src/datavisualization/data/surfaceitemmodelhandler.cpp
index bc85847c..d32b442b 100644
--- a/src/datavisualization/data/surfaceitemmodelhandler.cpp
+++ b/src/datavisualization/data/surfaceitemmodelhandler.cpp
@@ -23,7 +23,8 @@ QT_DATAVISUALIZATION_BEGIN_NAMESPACE
 
 SurfaceItemModelHandler::SurfaceItemModelHandler(QItemModelSurfaceDataProxy *proxy, QObject *parent)
     : AbstractItemModelHandler(parent),
-      m_proxy(proxy)
+      m_proxy(proxy),
+      m_proxyArray(0)
 {
 }
 
@@ -51,7 +52,6 @@ void SurfaceItemModelHandler::resolveModel()
     float minColumnValue = 0.0f;
     float maxColumnValue = 1.0f;
 
-    QSurfaceDataArray *newProxyArray = new QSurfaceDataArray;
     QHash<int, QByteArray> roleHash = m_itemModel->roleNames();
 
     // Default to display role if no mapping
@@ -60,11 +60,20 @@ void SurfaceItemModelHandler::resolveModel()
     int columnCount = m_itemModel->columnCount();
 
     if (mapping->useModelCategories()) {
+        // If dimensions have changed, recreate the array
+        if (!m_proxyArray || columnCount != m_proxy->columnCount()
+                || rowCount != m_proxyArray->size()) {
+            m_proxyArray = new QSurfaceDataArray;
+            m_proxyArray->reserve(rowCount);
+            for (int i = 0; i < rowCount; i++) {
+                QSurfaceDataRow *newProxyRow = new QSurfaceDataRow(columnCount);
+                m_proxyArray->append(newProxyRow);
+            }
+        }
         for (int i = 0; i < rowCount; i++) {
-            QSurfaceDataRow *newProxyRow = new QSurfaceDataRow(columnCount);
+            QSurfaceDataRow &newProxyRow = *m_proxyArray->at(i);
             for (int j = 0; j < columnCount; j++)
-                (*newProxyRow)[j] = m_itemModel->index(i, j).data(valueRole).toReal();
-            newProxyArray->append(newProxyRow);
+                newProxyRow[j] = m_itemModel->index(i, j).data(valueRole).toReal();
         }
         if (rowCount) {
             minRowValue = m_itemModel->headerData(0, Qt::Vertical).toFloat();
@@ -118,12 +127,22 @@ void SurfaceItemModelHandler::resolveModel()
         else
             columnList = mapping->columnCategories();
 
-        // Create new data array from itemValueMap
-        foreach (QString rowKey, rowList) {
-            QSurfaceDataRow *newProxyRow = new QSurfaceDataRow(columnList.size());
-            for (int i = 0; i < columnList.size(); i++)
-                (*newProxyRow)[i] = itemValueMap[rowKey][columnList.at(i)];
-            newProxyArray->append(newProxyRow);
+        // If dimensions have changed, recreate the array
+        if (!m_proxyArray || columnList.size() != m_proxy->columnCount()
+                || rowList.size() != m_proxyArray->size()) {
+            m_proxyArray = new QSurfaceDataArray;
+            m_proxyArray->reserve(rowList.size());
+            for (int i = 0; i < rowList.size(); i++) {
+                QSurfaceDataRow *newProxyRow = new QSurfaceDataRow(columnList.size());
+                m_proxyArray->append(newProxyRow);
+            }
+        }
+        // Create data array from itemValueMap
+        for (int i = 0; i < rowList.size(); i++) {
+            QString rowKey = rowList.at(i);
+            QSurfaceDataRow &newProxyRow = *m_proxyArray->at(i);
+            for (int j = 0; j < columnList.size(); j++)
+                newProxyRow[j] = itemValueMap[rowKey][columnList.at(j)];
         }
 
         // Use first and last roles converted to values for limits
@@ -137,7 +156,7 @@ void SurfaceItemModelHandler::resolveModel()
         }
     }
 
-    m_proxy->resetArray(newProxyArray, minRowValue, maxRowValue, minColumnValue, maxColumnValue);
+    m_proxy->resetArray(m_proxyArray, minRowValue, maxRowValue, minColumnValue, maxColumnValue);
 }
 
 QT_DATAVISUALIZATION_END_NAMESPACE
diff --git a/src/datavisualization/data/surfaceitemmodelhandler_p.h b/src/datavisualization/data/surfaceitemmodelhandler_p.h
index 045ac379..bcf642c5 100644
--- a/src/datavisualization/data/surfaceitemmodelhandler_p.h
+++ b/src/datavisualization/data/surfaceitemmodelhandler_p.h
@@ -45,6 +45,7 @@ protected:
     void virtual resolveModel();
 
     QItemModelSurfaceDataProxy *m_proxy; // Not owned
+    QSurfaceDataArray *m_proxyArray; // Not owned
 };
 
 QT_DATAVISUALIZATION_END_NAMESPACE