From 64735bfd46695ec6980195e50a4f167a64a9d3ab Mon Sep 17 00:00:00 2001
From: Manuel Nickschas <sputnick@quassel-irc.org>
Date: Fri, 15 Aug 2008 16:55:40 +0200
Subject: [PATCH] Introduce discardable LayoutData

---
 src/qtui/chatitem.cpp | 42 ++++++++++++++++++++++++------------------
 src/qtui/chatitem.h   | 21 ++++++++++++++++-----
 2 files changed, 40 insertions(+), 23 deletions(-)

diff --git a/src/qtui/chatitem.cpp b/src/qtui/chatitem.cpp
index 051151c5..da9bbf54 100644
--- a/src/qtui/chatitem.cpp
+++ b/src/qtui/chatitem.cpp
@@ -36,7 +36,7 @@ ChatItem::ChatItem(int col, QAbstractItemModel *model, QGraphicsItem *parent)
     _fontMetrics(0),
     _col(col),
     _lines(0),
-    _layout(0),
+    _layoutData(0),
     _selectionMode(NoSelection),
     _selectionStart(-1)
 {
@@ -48,7 +48,7 @@ ChatItem::ChatItem(int col, QAbstractItemModel *model, QGraphicsItem *parent)
 }
 
 ChatItem::~ChatItem() {
-  delete _layout;
+  delete _layoutData;
 }
 
 QVariant ChatItem::data(int role) const {
@@ -94,25 +94,31 @@ QTextLayout *ChatItem::createLayout(QTextOption::WrapMode wrapMode, Qt::Alignmen
   return layout;
 }
 
+void ChatItem::setLayout(QTextLayout *layout) {
+  if(!_layoutData)
+    _layoutData = new LayoutData;
+  _layoutData->layout = layout;
+}
+
 void ChatItem::updateLayout() {
   switch(data(ChatLineModel::ColumnTypeRole).toUInt()) {
     case ChatLineModel::TimestampColumn:
-      if(!haveLayout()) _layout = createLayout(QTextOption::WrapAnywhere, Qt::AlignLeft);
+      if(!haveLayout()) setLayout(createLayout(QTextOption::WrapAnywhere, Qt::AlignLeft));
       // fallthrough
     case ChatLineModel::SenderColumn:
-      if(!haveLayout()) _layout = createLayout(QTextOption::WrapAnywhere, Qt::AlignRight);
-      _layout->beginLayout();
+      if(!haveLayout()) setLayout(createLayout(QTextOption::WrapAnywhere, Qt::AlignRight));
+      layout()->beginLayout();
       {
-        QTextLine line = _layout->createLine();
+        QTextLine line = layout()->createLine();
         if(line.isValid()) {
           line.setLineWidth(width());
           line.setPosition(QPointF(0,0));
         }
-        _layout->endLayout();
+        layout()->endLayout();
       }
       break;
     case ChatLineModel::ContentsColumn: {
-      if(!haveLayout()) _layout = createLayout(QTextOption::WrapAnywhere);
+      if(!haveLayout()) setLayout(createLayout(QTextOption::WrapAnywhere));
 
       // Now layout
       ChatLineModel::WrapList wrapList = data(ChatLineModel::WrapListRole).value<ChatLineModel::WrapList>();
@@ -120,26 +126,26 @@ void ChatItem::updateLayout() {
 
       qreal h = 0;
       WrapColumnFinder finder(this);
-      _layout->beginLayout();
+      layout()->beginLayout();
       forever {
-        QTextLine line = _layout->createLine();
+        QTextLine line = layout()->createLine();
         if(!line.isValid())
           break;
 
         int col = finder.nextWrapColumn();
-        line.setNumColumns(col >= 0 ? col - line.textStart() : _layout->text().length());
+        line.setNumColumns(col >= 0 ? col - line.textStart() : layout()->text().length());
         line.setPosition(QPointF(0, h));
         h += line.height() + fontMetrics()->leading();
       }
-      _layout->endLayout();
+      layout()->endLayout();
     }
     break;
   }
 }
 
-void ChatItem::clearLayout() {
-  delete _layout;
-  _layout = 0;
+void ChatItem::clearLayoutData() {
+  delete _layoutData;
+  _layoutData = 0;
 }
 
 // NOTE: This is not the most time-efficient implementation, but it saves space by not caching unnecessary data
@@ -167,15 +173,15 @@ void ChatItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
     }
     formats.append(selectFmt);
   }
-  _layout->draw(painter, QPointF(0,0), formats, boundingRect());
+  layout()->draw(painter, QPointF(0,0), formats, boundingRect());
 }
 
 qint16 ChatItem::posToCursor(const QPointF &pos) {
   if(pos.y() > height()) return data(MessageModel::DisplayRole).toString().length();
   if(pos.y() < 0) return 0;
   if(!haveLayout()) updateLayout();
-  for(int l = _layout->lineCount() - 1; l >= 0; l--) {
-    QTextLine line = _layout->lineAt(l);
+  for(int l = layout()->lineCount() - 1; l >= 0; l--) {
+    QTextLine line = layout()->lineAt(l);
     if(pos.y() >= line.y()) {
       return line.xToCursor(pos.x(), QTextLine::CursorOnCharacter);
     }
diff --git a/src/qtui/chatitem.h b/src/qtui/chatitem.h
index cecd0121..678c3c6f 100644
--- a/src/qtui/chatitem.h
+++ b/src/qtui/chatitem.h
@@ -47,8 +47,8 @@ class ChatItem : public QGraphicsItem {
     inline qreal width() const { return _boundingRect.width(); }
     inline qreal height() const { return _boundingRect.height(); }
 
-    inline bool haveLayout() const { return _layout != 0; }
-    void clearLayout();
+    inline bool haveLayout() const { return _layoutData != 0 && layout() != 0; }
+    void clearLayoutData();
     void updateLayout();
     virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0);
 
@@ -73,6 +73,11 @@ class ChatItem : public QGraphicsItem {
     virtual void hoverMoveEvent(QGraphicsSceneHoverEvent *event);
 
   private:
+    struct LayoutData;
+    class WrapColumnFinder;
+
+    inline QTextLayout *layout() const;
+    void setLayout(QTextLayout *);
     qint16 posToCursor(const QPointF &pos);
     qreal computeHeight();
     QTextLayout *createLayout(QTextOption::WrapMode, Qt::Alignment = Qt::AlignLeft);
@@ -85,14 +90,20 @@ class ChatItem : public QGraphicsItem {
     int _col;
     quint8 _lines;
 
-    QTextLayout * _layout;
     QList<quint16> _wrapPositions;
 
     enum SelectionMode { NoSelection, PartialSelection, FullSelection };
     SelectionMode _selectionMode;
     qint16 _selectionStart, _selectionEnd;
 
-    class WrapColumnFinder;
+    LayoutData *_layoutData;
+};
+
+struct ChatItem::LayoutData {
+  QTextLayout *layout;
+
+  LayoutData() { layout = 0; }
+  ~LayoutData() { delete layout; }
 };
 
 class ChatItem::WrapColumnFinder {
@@ -115,6 +126,6 @@ class ChatItem::WrapColumnFinder {
 
 #include "chatline.h"
 inline int ChatItem::row() const { return static_cast<ChatLine *>(parentItem())->row(); }
-
+inline QTextLayout *ChatItem::layout() const { return _layoutData->layout; }
 
 #endif
-- 
2.20.1