Refactor the QtGraphicsTableView layout function.

3 files changed, 123 insertions, 44 deletions

diff --git a/src/qgraphicstableview.cpp b/src/qgraphicstableview.cpp
index 643b83a..e7fe534 100644
--- a/src/qgraphicstableview.cpp
+++ b/src/qgraphicstableview.cpp
@@ -25,11 +25,11 @@
 #include "qgraphicstableview_p.h"
 
 #include "qtablemodelinterface.h"
-#include "qtableselectionmanager.h"
 #include "qgraphicsheader.h"
 #include "qtablecontroller.h"
 
 #include <qdebug.h>
+#include <qstack.h>
 #include <qpainter.h>
 #include <qstyle.h>
 #include <qstyleoption.h>
@@ -112,8 +112,8 @@ void QtGraphicsTableViewItem::itemChanged(const QList<int> &roles)
 {
     Q_UNUSED(roles);
     // ### if the size changed, we need to let the layout know
-    prepareGeometryChange();
-    update();
+    //prepareGeometryChange();
+    //update();
 }
 
 QHash<int, QVariant> QtGraphicsTableViewItem::data(const QList<int> &roles) const
@@ -138,19 +138,19 @@ void QtGraphicsTableViewItem::paint(QPainter *painter, const QStyleOptionGraphic
     d->view->initStyleOption(&d->option);
     d->view->copyStyleOptionState(option, &d->option);
     d->view->initStyleOption(&d->option, d->row, d->column);
-    d->option.rect = QRectF(QPointF(), size()).toRect();
+    const QRect rect = QRectF(QPointF(), size()).toRect();
+    d->option.rect = rect;
     style()->drawControl(QStyle::CE_ItemViewItem, &d->option, painter, widget);
     // draw grid
     const QColor gridColor = static_cast<QRgb>(style()->styleHint(QStyle::SH_Table_GridLineColor, &d->option, widget));
-// TODO check for option and make the left+top painting ones actually work
     // left
-    //painter->fillRect(d->option.rect.left(), d->option.rect.bottom(), d->option.rect.width(), 1, gridColor);
+    //painter->fillRect(rect.left(), rect.bottom(), rect.width(), 1, gridColor);
     // top
-    //painter->fillRect(d->option.rect.right(), d->option.rect.top(), 1, d->option.rect.height(), gridColor);
+    //painter->fillRect(right(), d->option.rect.top(), 1, rect.height(), gridColor);
     // right
-    painter->fillRect(d->option.rect.left(), d->option.rect.bottom(), d->option.rect.width(), 1, gridColor);
+    painter->fillRect(rect.left(), rect.bottom(), rect.width(), 1, gridColor);
     // bottom
-    painter->fillRect(d->option.rect.right(), d->option.rect.top(), 1, d->option.rect.height(), gridColor);
+    painter->fillRect(rect.right(), rect.top(), 1, rect.height(), gridColor);
 }
 /*!
   \class QtGraphicsTableViewItemCreatorBase
@@ -241,12 +241,18 @@ void QtGraphicsTableViewPrivate::_q_cellsChanged(int firstRow, int firstColumn,
 void QtGraphicsTableViewPrivate::_q_selectionsChanged(const QList<QtTableSelectionRange> &changed)
 {
     // ### FIXME: naive lookup
-    for (int i = 0; i < items.count(); ++i) {
-        for (int j = 0; j < changed.count(); ++j) {
-            QtGraphicsTableViewItem *item = items.at(i);
-            if (changed.at(j).containsCell(item->row(), item->column())) {
-                item->update();
-                break;
+    // ### FIXME: check header mappings
+    if (!model)
+        return;
+    const int columnCount = model->columnCount();
+    for (int j = 0; j < changed.count(); ++j) {
+        QtTableSelectionRange range = changed.at(j);
+        if (range.intersects(visibleSections)) {
+            for (int row = range.topRow(); row <= range.bottomRow(); ++row) {
+                for (int column = range.leftColumn(); column <= range.rightColumn(); ++column) {
+                    if (QtGraphicsTableViewItem *item = items.value((row * columnCount) + column))
+                        item->update();
+                }
             }
         }
     }
@@ -254,14 +260,13 @@ void QtGraphicsTableViewPrivate::_q_selectionsChanged(const QList<QtTableSelecti
 
 void QtGraphicsTableViewPrivate::_q_currentChanged(int currentRow, int currentColumn, int previousRow, int previousColumn)
 {
-    Q_UNUSED(previousColumn);
-    Q_UNUSED(previousRow);
-    // ### FIXME: naive lookup
-    for (int i = 0; i < items.count(); ++i) {
-        QtGraphicsTableViewItem *item = items.at(i);
-        if (item->row() == currentRow && item->column() == currentColumn)
-            item->update();
-    }
+    if (!model)
+        return;
+    const int columnCount = model->columnCount();
+    if (QtGraphicsTableViewItem *current = items.value((currentRow * columnCount) + currentColumn))
+        current->update();
+    if (QtGraphicsTableViewItem *previous = items.value((previousRow * columnCount) + previousColumn))
+        previous->update();
 }
 
 void QtGraphicsTableViewPrivate::_q_rowsInserted(int row, int count)
@@ -948,6 +953,9 @@ void QtGraphicsTableView::doLayout()
     if (area.isEmpty())
         return;
 
+    const int columnCount = d->model->columnCount();
+    const int rowCount = d->model->rowCount();
+
     int horizontalCount;
     qreal horizontalOffset;
     QVector<int> horizontalMapping;
@@ -957,7 +965,7 @@ void QtGraphicsTableView::doLayout()
         horizontalOffset = d->horizontalHeader->offset();
         horizontalMapping = d->horizontalHeader->indexMapping();
     } else {
-        horizontalCount = qMin(d->model->columnCount(), int(area.width() / d->defaultColumnWidth));
+        horizontalCount = qMin(columnCount, int(area.width() / d->defaultColumnWidth));
         horizontalOffset = d->horizontalOffset;
     }
 
@@ -970,30 +978,93 @@ void QtGraphicsTableView::doLayout()
         verticalOffset = d->verticalHeader->offset();
         verticalMapping = d->verticalHeader->indexMapping();
     } else {
-        verticalCount = qMin(d->model->rowCount(), int(area.height() / d->defaultRowHeight));
+        verticalCount = qMin(rowCount, int(area.height() / d->defaultRowHeight));
         verticalOffset = d->verticalOffset;
     }
 
-    const int lastColumn = qMax(d->firstColumn + horizontalCount - 1, 0);
-    const int lastRow = qMax(d->firstRow + verticalCount - 1, 0);
-    const int firstIndex = (d->firstRow * horizontalCount) + d->firstColumn;
+    const int firstHorizontalSection = d->firstColumn;
+    const int firstVerticalSection = d->firstRow;
+    const int lastHorizontalSection = qMax(d->firstColumn + horizontalCount - 1, -1);
+    const int lastVerticalSection = qMax(d->firstRow + verticalCount - 1, -1);
+
+    const int oldFirstVerticalSection = d->visibleSections.topRow();
+    const int oldFirstHorizontalSection = d->visibleSections.leftColumn();
+    const int oldLastVerticalSection = d->visibleSections.bottomRow();
+    const int oldLastHorizontalSection = d->visibleSections.rightColumn();
+
+    // find unused items for reassignment
+    QStack<QtGraphicsTableViewItem*> unused;
+
+    /*
+    --------------
+    |            |
+    --------------
+    |  |      |  |
+    |  |      |  |
+    |  |      |  |
+    --------------
+    |            |
+    --------------
+    */
+
+    // top edge
+    for (int verticalSection = oldFirstVerticalSection; verticalSection < firstVerticalSection; ++verticalSection) {
+        const int row = verticalMapping.value(verticalSection, verticalSection);
+        for (int horizontalSection = oldFirstHorizontalSection; horizontalSection <= oldLastHorizontalSection; ++horizontalSection) {
+            const int column = horizontalMapping.value(horizontalSection, horizontalSection);
+            const int index = (row * columnCount) + column;
+            if (QtGraphicsTableViewItem *item = d->items.take(index))
+                unused.push(item);
+        }
+    }
+    // left edge
+    for (int horizontalSection = oldFirstHorizontalSection; horizontalSection < firstHorizontalSection; ++horizontalSection) {
+        int column = horizontalMapping.value(horizontalSection, horizontalSection);
+        for (int verticalSection = firstVerticalSection; verticalSection <= lastVerticalSection; ++verticalSection) {
+            const int row = verticalMapping.value(verticalSection, verticalSection);
+            const int index = (row * columnCount) + column;
+            if (QtGraphicsTableViewItem *item = d->items.take(index))
+                unused.push(item);
+        }
+    }
+    // bottom edge
+    for (int verticalSection = lastVerticalSection + 1; verticalSection <= oldLastVerticalSection; ++verticalSection) {
+        const int row = verticalMapping.value(verticalSection, verticalSection);
+        for (int horizontalSection = oldFirstHorizontalSection; horizontalSection <= oldLastHorizontalSection; ++horizontalSection) {
+            const int column = horizontalMapping.value(horizontalSection, horizontalSection);
+            const int index = (row * columnCount) + column;
+            if (QtGraphicsTableViewItem *item = d->items.take(index))
+                unused.push(item);
+        }
+    }
+    // right edge
+    for (int horizontalSection = lastHorizontalSection + 1; horizontalSection <= oldLastHorizontalSection; ++horizontalSection) {
+        int column = horizontalMapping.value(horizontalSection, horizontalSection);
+        for (int verticalSection = firstVerticalSection; verticalSection <= lastVerticalSection; ++verticalSection) {
+            const int row = verticalMapping.value(verticalSection, verticalSection);
+            const int index = (row * columnCount) + column;
+            if (QtGraphicsTableViewItem *item = d->items.take(index))
+                unused.push(item);
+        }
+    }
 
+    // move overlapping items
     qreal y = -verticalOffset;
-    for (int verticalSection = d->firstRow; verticalSection <= lastRow; ++verticalSection) {
+    for (int verticalSection = firstVerticalSection; verticalSection <= lastVerticalSection; ++verticalSection) {
         const int row = verticalMapping.value(verticalSection, verticalSection);
         const qreal height = rowHeight(row);
         qreal x = -horizontalOffset;
-        for (int horizontalSection = d->firstColumn; horizontalSection <= lastColumn; ++horizontalSection) {
+        for (int horizontalSection = firstHorizontalSection; horizontalSection <= lastHorizontalSection; ++horizontalSection) {
             const int column = horizontalMapping.value(horizontalSection, horizontalSection);
             const qreal width = columnWidth(column);
-            const int index = ((verticalSection * horizontalCount) + horizontalSection) - firstIndex;
-            QtGraphicsTableViewItem *item = d->items.value(index, 0);
-            // ### FIXME: scroll the items properly
-            if (item) {
-                item = d->creator->reassign(row, column, item);
-            } else if (index >= d->items.count()) {
-                item = d->creator->create(row, column, this);
-                d->items.append(item);
+            const int index = (row * columnCount) + column;
+            QtGraphicsTableViewItem *item = d->items.value(index);
+            if (!item) {
+                if (!unused.isEmpty())
+                    item = d->creator->reassign(row, column, unused.pop());
+                else
+                    item = d->creator->create(row, column, this);
+                d->items.insert(index, item);
             }
             item->setGeometry(x, y, width, height);
             x += width;
@@ -1001,10 +1072,15 @@ void QtGraphicsTableView::doLayout()
         y += height;
     }
 
-    const int lastIndex = (lastRow * horizontalCount) + lastColumn;
-    const int removeCount = d->items.count() - (lastIndex - firstIndex) - 1;
-    for (int i = 0; i < removeCount; ++i)
-        d->creator->recycle(d->items.takeLast());
+    // update internal structures
+    d->visibleSections.setRange(firstVerticalSection, firstHorizontalSection, lastVerticalSection, lastHorizontalSection);
+
+    // recycle any unused items left
+    for (int i = 0; i < unused.count(); ++i)
+        d->creator->recycle(unused.at(i));
+
+    Q_ASSERT(d->items.count() == (horizontalCount * verticalCount));
+    //Q_ASSERT(d->items.count() == childItems().count());
 }
 
 /*!
diff --git a/src/qgraphicstableview.h b/src/qgraphicstableview.h
index ee3950f..9c561f6 100644
--- a/src/qgraphicstableview.h
+++ b/src/qgraphicstableview.h
@@ -123,7 +123,6 @@ public:
     void setTextElideMode(Qt::TextElideMode mode);
 
     bool isGridShown() const;
-    void setGridShown(bool show);
 
     qreal rowHeight(int row) const;
     void setRowHeight(int row, qreal height);
@@ -183,6 +182,7 @@ public:
     void copyStyleOptionState(const QStyleOptionGraphicsItem *source, QStyleOptionViewItemV4 *dest);
 
 public Q_SLOTS:
+    void setGridShown(bool show);
     void setFirstRow(int row);
     void setFirstColumn(int column);
     void setHorizontalOffset(qreal offset);
diff --git a/src/qgraphicstableview_p.h b/src/qgraphicstableview_p.h
index c8e5c61..800f2c7 100644
--- a/src/qgraphicstableview_p.h
+++ b/src/qgraphicstableview_p.h
@@ -39,6 +39,8 @@
 #include <qfont.h>
 #include <qvariant.h>
 
+#include <qtableselectionmanager.h>
+
 QT_BEGIN_NAMESPACE
 
 class QtTableModelInterface;
@@ -114,7 +116,8 @@ public:
     mutable int cachedDataColumn;
 
     // view items
-    QList<QtGraphicsTableViewItem*> items;
+    QtTableSelectionRange visibleSections;
+    QHash<int, QtGraphicsTableViewItem*> items;
     QtGraphicsTableViewItemCreatorBase *creator;
 
     QtGraphicsTableView *q_ptr;