]> git.lyx.org Git - lyx.git/blobdiff - src/frontends/qt4/GuiWorkArea.cpp
Complete the removal of the embedding stuff. Maybe. It's hard to be sure we got every...
[lyx.git] / src / frontends / qt4 / GuiWorkArea.cpp
index 6b7b3ed7e729335c483f513b6142f1b45ca6f327..79277e7ff10582389b04b94e1f2331348ab842d1 100644 (file)
@@ -23,7 +23,6 @@
 #include "GuiApplication.h"
 #include "GuiKeySymbol.h"
 #include "GuiPainter.h"
-#include "GuiPopupMenu.h"
 #include "GuiView.h"
 #include "KeySymbol.h"
 #include "Language.h"
@@ -31,6 +30,7 @@
 #include "LyXRC.h"
 #include "MetricsInfo.h"
 #include "qt_helpers.h"
+#include "Text.h"
 #include "version.h"
 
 #include "graphics/GraphicsImage.h"
 #include <QContextMenuEvent>
 #include <QInputContext>
 #include <QHelpEvent>
+#ifdef Q_WS_MACX
+#include <QMacStyle>
+#endif
 #include <QMainWindow>
+#include <QMenu>
 #include <QPainter>
 #include <QPalette>
+#include <QPixmapCache>
 #include <QScrollBar>
-#include <QTabBar>
 #include <QTimer>
 #include <QToolButton>
 #include <QToolTip>
@@ -68,6 +72,7 @@ int const CursorWidth = 2;
 #else
 int const CursorWidth = 1;
 #endif
+int const TabIndicatorWidth = 3;
 
 #undef KeyPress
 #undef NoModifier 
@@ -121,44 +126,71 @@ public:
 
        void draw(QPainter & painter)
        {
-               if (show_ && rect_.isValid()) {
-                       switch (shape_) {
-                       case L_SHAPE:
-                               painter.fillRect(rect_.x(), rect_.y(), CursorWidth, rect_.height(), color_);
-                               painter.setPen(color_);
-                               painter.drawLine(rect_.bottomLeft().x() + CursorWidth, rect_.bottomLeft().y(),
-                                                                                                rect_.bottomRight().x(), rect_.bottomLeft().y());
-                               break;
-                       
-                       case REVERSED_L_SHAPE:
-                               painter.fillRect(rect_.x() + rect_.height() / 3, rect_.y(), CursorWidth, rect_.height(), color_);
-                               painter.setPen(color_);
-                               painter.drawLine(rect_.bottomRight().x() - CursorWidth, rect_.bottomLeft().y(),
-                                                                                                        rect_.bottomLeft().x(), rect_.bottomLeft().y());
-                               break;
-                                       
-                       default:
-                               painter.fillRect(rect_, color_);
-                               break;
+               if (!show_ || !rect_.isValid())
+                       return;
+               
+               int y = rect_.top();
+               int l = x_ - rect_.left();
+               int r = rect_.right() - x_;
+               int bot = rect_.bottom();
+
+               // draw vertica linel
+               painter.fillRect(x_, y, CursorWidth, rect_.height(), color_);
+               
+               // draw RTL/LTR indication
+               painter.setPen(color_);
+               if (l_shape_) {
+                       if (rtl_)
+                               painter.drawLine(x_, bot, x_ - l, bot);
+                       else
+                               painter.drawLine(x_, bot, x_ + CursorWidth + r, bot);
+               }
+               
+               // draw completion triangle
+               if (completable_) {
+                       int m = y + rect_.height() / 2;
+                       int d = TabIndicatorWidth - 1;
+                       if (rtl_) {
+                               painter.drawLine(x_ - 1, m - d, x_ - 1 - d, m);
+                               painter.drawLine(x_ - 1, m + d, x_ - 1 - d, m);
+                       } else {
+                               painter.drawLine(x_ + CursorWidth, m - d, x_ + CursorWidth + d, m);
+                               painter.drawLine(x_ + CursorWidth, m + d, x_ + CursorWidth + d, m);
                        }
                }
        }
 
-       void update(int x, int y, int h, CursorShape shape)
+       void update(int x, int y, int h, bool l_shape,
+               bool rtl, bool completable)
        {
                color_ = guiApp->colorCache().get(Color_cursor);
-               shape_ = shape;
-               switch (shape) {
-               case L_SHAPE:
-                       rect_ = QRect(x, y, CursorWidth + h / 3, h);
-                       break;
-               case REVERSED_L_SHAPE:
-                       rect_ = QRect(x - h / 3, y, CursorWidth + h / 3, h);
-                       break;
-               default: 
-                       rect_ = QRect(x, y, CursorWidth, h);
-                       break;
+               l_shape_ = l_shape;
+               rtl_ = rtl;
+               completable_ = completable;
+               x_ = x;
+               
+               // extension to left and right
+               int l = 0;
+               int r = 0;
+
+               // RTL/LTR indication
+               if (l_shape_) {
+                       if (rtl)
+                               l += h / 3;
+                       else
+                               r += h / 3;
                }
+               
+               // completion triangle
+               if (completable_) {
+                       if (rtl)
+                               l = max(l, TabIndicatorWidth);
+                       else
+                               r = max(r, TabIndicatorWidth);
+               }
+
+               // compute overall rectangle
+               rect_ = QRect(x - l, y, CursorWidth + r + l, h);
        }
 
        void show(bool set_show = true) { show_ = set_show; }
@@ -167,14 +199,20 @@ public:
        QRect const & rect() { return rect_; }
 
 private:
-       ///
-       CursorShape shape_;
+       /// cursor is in RTL or LTR text
+       bool rtl_;
+       /// indication for RTL or LTR
+       bool l_shape_;
+       /// triangle to show that a completion is available
+       bool completable_;
        ///
        bool show_;
        ///
        QColor color_;
-       ///
+       /// rectangle, possibly with l_shape and completion triangle
        QRect rect_;
+       /// x position (were the vertical line is drawn)
+       int x_;
 };
 
 
@@ -202,18 +240,35 @@ GuiWorkArea::GuiWorkArea(Buffer & buffer, GuiView & lv)
        if (time > 0) {
                cursor_timeout_.setInterval(time);
                cursor_timeout_.start();
-       } else
+       } else {
                // let's initialize this just to be safe
                cursor_timeout_.setInterval(500);
+       }
 
        screen_ = QPixmap(viewport()->width(), viewport()->height());
        cursor_ = new frontend::CursorWidget();
        cursor_->hide();
 
+       // HACK: Prevents an additional redraw when the scrollbar pops up
+       // which regularily happens on documents with more than one page.
+       // The policy  should be set to "Qt::ScrollBarAsNeeded" soon.
+       // Since we have no geometry information yet, we assume that
+       // a document needs a scrollbar if there is more then four
+       // paragraph in the outermost text.
+       if (buffer.text().paragraphs().size() > 4)
+               setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
+       QTimer::singleShot(50, this, SLOT(fixVerticalScrollBar()));
+
+
        setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
        setAcceptDrops(true);
        setMouseTracking(true);
        setMinimumSize(100, 70);
+#ifdef Q_WS_MACX
+       setFrameStyle(QFrame::NoFrame); 
+#else
+       setFrameStyle(QFrame::Box);
+#endif
        updateWindowTitle();
 
        viewport()->setAutoFillBackground(false);
@@ -250,6 +305,13 @@ GuiWorkArea::~GuiWorkArea()
 }
 
 
+void GuiWorkArea::fixVerticalScrollBar()
+{
+       if (!isFullScreen())
+               setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
+}
+
+
 void GuiWorkArea::close()
 {
        lyx_view_->removeWorkArea(this);
@@ -264,7 +326,11 @@ void GuiWorkArea::setFullScreen(bool full_screen)
                if (lyxrc.full_screen_scrollbar)
                        setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
        } else {
+#ifdef Q_WS_MACX
+               setFrameStyle(QFrame::NoFrame); 
+#else
                setFrameStyle(QFrame::Box);
+#endif
                setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
        }
 }
@@ -346,7 +412,6 @@ void GuiWorkArea::processKeySym(KeySymbol const & key, KeyModifier mod)
 
        theLyXFunc().setLyXView(lyx_view_);
        theLyXFunc().processKeySym(key, mod);
-       
 }
 
 
@@ -428,22 +493,19 @@ void GuiWorkArea::showCursor()
        if (cursor_visible_)
                return;
 
-       CursorShape shape = BAR_SHAPE;
-
+       // RTL or not RTL
+       bool l_shape = false;
        Font const & realfont = buffer_view_->cursor().real_current_font;
        BufferParams const & bp = buffer_view_->buffer().params();
        bool const samelang = realfont.language() == bp.language;
        bool const isrtl = realfont.isVisibleRightToLeft();
 
-       if (!samelang || isrtl != bp.language->rightToLeft()) {
-               shape = L_SHAPE;
-               if (isrtl)
-                       shape = REVERSED_L_SHAPE;
-       }
+       if (!samelang || isrtl != bp.language->rightToLeft())
+               l_shape = true;
 
        // The ERT language hack needs fixing up
        if (realfont.language() == latex_language)
-               shape = BAR_SHAPE;
+               l_shape = false;
 
        Font const font = buffer_view_->cursor().getFont();
        FontMetrics const & fm = theFontMetrics(font);
@@ -462,9 +524,13 @@ void GuiWorkArea::showCursor()
                cursorInView = false;
 
        // show cursor on screen
+       bool completable = cur.inset().showCompletionCursor()
+               && completer_.completionAvailable()
+               && !completer_.popupVisible()
+               && !completer_.inlineVisible();
        if (cursorInView) {
                cursor_visible_ = true;
-               showCursor(x, y, h, shape);
+               showCursor(x, y, h, l_shape, isrtl, completable);
        }
 }
 
@@ -492,11 +558,11 @@ void GuiWorkArea::updateScrollbar()
 {
        ScrollbarParameters const & scroll_ = buffer_view_->scrollbarParameters();
 
+       // Block the scrollbar signal to prevent recursive signal/slot calling.
+       verticalScrollBar()->blockSignals(true);
        verticalScrollBar()->setRange(scroll_.min, scroll_.max);
        verticalScrollBar()->setPageStep(scroll_.page_step);
        verticalScrollBar()->setSingleStep(scroll_.single_step);
-       // Block the scrollbar signal to prevent recursive signal/slot calling.
-       verticalScrollBar()->blockSignals(true);
        verticalScrollBar()->setValue(scroll_.position);
        verticalScrollBar()->setSliderPosition(scroll_.position);
        verticalScrollBar()->blockSignals(false);
@@ -564,7 +630,7 @@ void GuiWorkArea::contextMenuEvent(QContextMenuEvent * e)
                QAbstractScrollArea::contextMenuEvent(e);
                return;
        }
-       QMenu * menu = guiApp->menus().menu(toqstr(name));
+       QMenu * menu = guiApp->menus().menu(toqstr(name), *lyx_view_);
        if (!menu) {
                QAbstractScrollArea::contextMenuEvent(e);
                return;
@@ -578,7 +644,9 @@ void GuiWorkArea::contextMenuEvent(QContextMenuEvent * e)
 
 void GuiWorkArea::focusInEvent(QFocusEvent * e)
 {
-       lyx_view_->setCurrentWorkArea(this);
+       if (lyx_view_->currentWorkArea() != this)
+               lyx_view_->setCurrentWorkArea(this);
+
        // Repaint the whole screen.
        // Note: this is different from redraw() as only the backing pixmap
        // will be redrawn, which is cheap.
@@ -695,19 +763,29 @@ void GuiWorkArea::mouseMoveEvent(QMouseEvent * e)
 }
 
 
-void GuiWorkArea::wheelEvent(QWheelEvent * e)
+void GuiWorkArea::wheelEvent(QWheelEvent * ev)
 {
        // Wheel rotation by one notch results in a delta() of 120 (see
        // documentation of QWheelEvent)
-       double const lines = qApp->wheelScrollLines()
-               * lyxrc.mouse_wheel_speed
-               * e->delta() / 120.0;
-       LYXERR(Debug::SCROLLING, "wheelScrollLines = " << qApp->wheelScrollLines()
-               << " delta = " << e->delta()
-               << " lines = " << lines);
-       verticalScrollBar()->setValue(verticalScrollBar()->value() -
-               int(lines *  verticalScrollBar()->singleStep()));
-       e->accept();
+       int delta = ev->delta() / 120;
+       if (ev->modifiers() & Qt::ControlModifier) {
+               lyxrc.zoom -= 5 * delta;
+               if (lyxrc.zoom < 10)
+                       lyxrc.zoom = 10;
+               // The global QPixmapCache is used in GuiPainter to cache text
+               // painting so we must reset it.
+               QPixmapCache::clear();
+               guiApp->fontLoader().update();
+               lyx::dispatch(FuncRequest(LFUN_SCREEN_FONT_UPDATE));
+       } else {
+               double const lines = qApp->wheelScrollLines()
+                       * lyxrc.mouse_wheel_speed * delta;
+               LYXERR(Debug::SCROLLING, "wheelScrollLines = " << qApp->wheelScrollLines()
+                       << " delta = " << ev->delta() << " lines = " << lines);
+               verticalScrollBar()->setValue(verticalScrollBar()->value() -
+                       int(lines *  verticalScrollBar()->singleStep()));
+       }
+       ev->accept();
 }
 
 
@@ -743,13 +821,25 @@ void GuiWorkArea::keyPressEvent(QKeyEvent * ev)
                }
        }
        
-       // intercept tab for inline completion
+       // intercept keys for the completion
        if (ev->key() == Qt::Key_Tab) {
                completer_.tab();
                ev->accept();
                return;
+       } 
+
+       if (completer_.popupVisible() && ev->key() == Qt::Key_Escape) {
+               completer_.hidePopup();
+               ev->accept();
+               return;
        }
-       
+
+       if (completer_.inlineVisible() && ev->key() == Qt::Key_Escape) {
+               completer_.hideInline();
+               ev->accept();
+               return;
+       }
+
        // do nothing if there are other events
        // (the auto repeated events come too fast)
        // \todo FIXME: remove hard coded Qt keys, process the key binding
@@ -833,7 +923,8 @@ void GuiWorkArea::updateScreen()
 }
 
 
-void GuiWorkArea::showCursor(int x, int y, int h, CursorShape shape)
+void GuiWorkArea::showCursor(int x, int y, int h,
+       bool l_shape, bool rtl, bool completable)
 {
        if (schedule_redraw_) {
                buffer_view_->updateMetrics();
@@ -846,7 +937,7 @@ void GuiWorkArea::showCursor(int x, int y, int h, CursorShape shape)
                return;
        }
 
-       cursor_->update(x, y, h, shape);
+       cursor_->update(x, y, h, l_shape, rtl, completable);
        cursor_->show();
        viewport()->update(cursor_->rect());
 }
@@ -1054,14 +1145,53 @@ void GuiWorkArea::setReadOnly(bool)
 }
 
 
+bool GuiWorkArea::isFullScreen()
+{
+       return lyx_view_ && lyx_view_->isFullScreen();
+}
+
+
 ////////////////////////////////////////////////////////////////////
 //
 // TabWorkArea 
 //
 ////////////////////////////////////////////////////////////////////
 
-TabWorkArea::TabWorkArea(QWidget * parent) : QTabWidget(parent)
+#ifdef Q_WS_MACX
+class NoTabFrameMacStyle : public QMacStyle {
+public:
+       ///
+       QRect subElementRect(SubElement element, const QStyleOption * option,
+                            const QWidget * widget = 0) const
+       {
+               QRect rect = QMacStyle::subElementRect(element, option, widget);
+               bool noBar = static_cast<QTabWidget const *>(widget)->count() <= 1;
+               
+               // The Qt Mac style puts the contents into a 3 pixel wide box
+               // which looks very ugly and not like other Mac applications.
+               // Hence we remove this here, and moreover the 16 pixel round
+               // frame above if the tab bar is hidden.
+               if (element == QStyle::SE_TabWidgetTabContents) {
+                       rect.adjust(- rect.left(), 0, rect.left(), 0);
+                       if (noBar)
+                               rect.setTop(0);
+               }
+
+               return rect;
+       }
+};
+
+NoTabFrameMacStyle noTabFrameMacStyle;
+#endif
+
+
+TabWorkArea::TabWorkArea(QWidget * parent)
+       : QTabWidget(parent), clicked_tab_(-1)
 {
+#ifdef Q_WS_MACX
+       setStyle(&noTabFrameMacStyle);
+#endif
+
        QPalette pal = palette();
        pal.setColor(QPalette::Active, QPalette::Button,
                pal.color(QPalette::Active, QPalette::Window));
@@ -1074,30 +1204,29 @@ TabWorkArea::TabWorkArea(QWidget * parent) : QTabWidget(parent)
                this, SLOT(on_currentTabChanged(int)));
 
        QToolButton * closeBufferButton = new QToolButton(this);
-    closeBufferButton->setPalette(pal);
+       closeBufferButton->setPalette(pal);
        // FIXME: rename the icon to closebuffer.png
        closeBufferButton->setIcon(QIcon(":/images/closetab.png"));
-       closeBufferButton->setText("Close Buffer");
+       closeBufferButton->setText("Close File");
        closeBufferButton->setAutoRaise(true);
        closeBufferButton->setCursor(Qt::ArrowCursor);
-       closeBufferButton->setToolTip(tr("Close Buffer"));
+       closeBufferButton->setToolTip(qt_("Close File"));
        closeBufferButton->setEnabled(true);
        QObject::connect(closeBufferButton, SIGNAL(clicked()),
                this, SLOT(closeCurrentBuffer()));
        setCornerWidget(closeBufferButton, Qt::TopRightCorner);
-
-       QToolButton * closeTabButton = new QToolButton(this);
-    closeTabButton->setPalette(pal);
-       closeTabButton->setIcon(QIcon(":/images/hidetab.png"));
-       closeTabButton->setText("Hide tab");
-       closeTabButton->setAutoRaise(true);
-       closeTabButton->setCursor(Qt::ArrowCursor);
-       closeTabButton->setToolTip(tr("Hide tab"));
-       closeTabButton->setEnabled(true);
-       QObject::connect(closeTabButton, SIGNAL(clicked()),
-               this, SLOT(closeCurrentTab()));
-       setCornerWidget(closeTabButton, Qt::TopLeftCorner);
-
+       
+       // setup drag'n'drop
+       QTabBar* tb = new DragTabBar;
+       connect(tb, SIGNAL(tabMoveRequested(int, int)),
+               this, SLOT(moveTab(int, int)));
+       setTabBar(tb);
+
+       // make us responsible for the context menu of the tabbar
+       tb->setContextMenuPolicy(Qt::CustomContextMenu);
+       connect(tb, SIGNAL(customContextMenuRequested(const QPoint &)),
+               this, SLOT(showContextMenu(const QPoint &)));
+       
        setUsesScrollButtons(true);
 }
 
@@ -1127,7 +1256,7 @@ GuiWorkArea * TabWorkArea::currentWorkArea()
                return 0;
 
        GuiWorkArea * wa = dynamic_cast<GuiWorkArea *>(currentWidget()); 
-       BOOST_ASSERT(wa);
+       LASSERT(wa, /**/);
        return wa;
 }
 
@@ -1136,7 +1265,7 @@ GuiWorkArea * TabWorkArea::workArea(Buffer & buffer)
 {
        for (int i = 0; i != count(); ++i) {
                GuiWorkArea * wa = dynamic_cast<GuiWorkArea *>(widget(i));
-               BOOST_ASSERT(wa);
+               LASSERT(wa, return 0);
                if (&wa->bufferView().buffer() == &buffer)
                        return wa;
        }
@@ -1148,7 +1277,7 @@ void TabWorkArea::closeAll()
 {
        while (count()) {
                GuiWorkArea * wa = dynamic_cast<GuiWorkArea *>(widget(0));
-               BOOST_ASSERT(wa);
+               LASSERT(wa, /**/);
                removeTab(0);
                delete wa;
        }
@@ -1157,7 +1286,7 @@ void TabWorkArea::closeAll()
 
 bool TabWorkArea::setCurrentWorkArea(GuiWorkArea * work_area)
 {
-       BOOST_ASSERT(work_area);
+       LASSERT(work_area, /**/);
        int index = indexOf(work_area);
        if (index == -1)
                return false;
@@ -1180,19 +1309,24 @@ GuiWorkArea * TabWorkArea::addWorkArea(Buffer & buffer, GuiView & view)
        wa->setUpdatesEnabled(false);
        // Hide tabbar if there's no tab (avoid a resize and a flashing tabbar
        // when hiding it again below).
-       showBar(count() > 0);
+       if (!(currentWorkArea() && currentWorkArea()->isFullScreen()))
+               showBar(count() > 0);
        addTab(wa, wa->windowTitle());
        QObject::connect(wa, SIGNAL(titleChanged(GuiWorkArea *)),
                this, SLOT(updateTabText(GuiWorkArea *)));
-       // Hide tabbar if there's only one tab.
-       showBar(count() > 1);
+       if (currentWorkArea() && currentWorkArea()->isFullScreen())
+               setFullScreen(true);
+       else
+               // Hide tabbar if there's only one tab.
+               showBar(count() > 1);
+
        return wa;
 }
 
 
 bool TabWorkArea::removeWorkArea(GuiWorkArea * work_area)
 {
-       BOOST_ASSERT(work_area);
+       LASSERT(work_area, return false);
        int index = indexOf(work_area);
        if (index == -1)
                return false;
@@ -1204,17 +1338,26 @@ bool TabWorkArea::removeWorkArea(GuiWorkArea * work_area)
        if (count()) {
                // make sure the next work area is enabled.
                currentWidget()->setUpdatesEnabled(true);
-               // Hide tabbar if there's only one tab.
-               showBar(count() > 1);
+               if (currentWorkArea() && currentWorkArea()->isFullScreen())
+                       setFullScreen(true);
+               else
+                       // Hide tabbar if there's only one tab.
+                       showBar(count() > 1);
+       } else {
+               lastWorkAreaRemoved();
        }
+
        return true;
 }
 
 
 void TabWorkArea::on_currentTabChanged(int i)
 {
+       // returns e.g. on application destruction
+       if (i == -1)
+               return;
        GuiWorkArea * wa = dynamic_cast<GuiWorkArea *>(widget(i));
-       BOOST_ASSERT(wa);
+       LASSERT(wa, return);
        BufferView & bv = wa->bufferView();
        bv.cursor().fixIfBroken();
        bv.updateMetrics();
@@ -1231,13 +1374,22 @@ void TabWorkArea::on_currentTabChanged(int i)
 
 void TabWorkArea::closeCurrentBuffer()
 {
+       if (clicked_tab_ != -1)
+               setCurrentIndex(clicked_tab_);
+
        lyx::dispatch(FuncRequest(LFUN_BUFFER_CLOSE));
 }
 
 
 void TabWorkArea::closeCurrentTab()
 {
-       removeWorkArea(currentWorkArea());
+       if (clicked_tab_ == -1)
+               removeWorkArea(currentWorkArea());
+       else {
+               GuiWorkArea * wa = dynamic_cast<GuiWorkArea *>(widget(clicked_tab_)); 
+               LASSERT(wa, /**/);
+               removeWorkArea(wa);
+       }
 }
 
 
@@ -1249,6 +1401,133 @@ void TabWorkArea::updateTabText(GuiWorkArea * wa)
        setTabText(i, wa->windowTitle());
 }
 
+
+void TabWorkArea::showContextMenu(const QPoint & pos)
+{
+       // which tab?
+       clicked_tab_ = static_cast<DragTabBar *>(tabBar())->tabAt(pos);
+       if (clicked_tab_ != -1) {
+               // show tab popup
+               QMenu popup;
+               popup.addAction(QIcon(":/images/hidetab.png"),
+                        qt_("Hide tab"), this, SLOT(closeCurrentTab()));
+               popup.addAction(QIcon(":/images/closetab.png"),
+                        qt_("Close tab"), this, SLOT(closeCurrentBuffer()));
+               popup.exec(tabBar()->mapToGlobal(pos));
+               
+               clicked_tab_ = -1;
+       }
+}
+
+
+void TabWorkArea::moveTab(int fromIndex, int toIndex)
+{
+       QWidget * w = widget(fromIndex);
+       QIcon icon = tabIcon(fromIndex);
+       QString text = tabText(fromIndex);
+
+       setCurrentIndex(fromIndex);
+       removeTab(fromIndex);
+       insertTab(toIndex, w, icon, text);
+       setCurrentIndex(toIndex);
+}
+       
+
+DragTabBar::DragTabBar(QWidget* parent)
+       : QTabBar(parent)
+{
+       setAcceptDrops(true);
+}
+
+
+#if QT_VERSION < 0x040300
+int DragTabBar::tabAt(QPoint const & position) const
+{
+       const int max = count();
+       for (int i = 0; i < max; ++i) {
+               if (tabRect(i).contains(position))
+                       return i;
+       }
+       return -1;
+}
+#endif
+
+
+void DragTabBar::mousePressEvent(QMouseEvent * event)
+{
+       if (event->button() == Qt::LeftButton)
+               dragStartPos_ = event->pos();
+       QTabBar::mousePressEvent(event);
+}
+
+
+void DragTabBar::mouseMoveEvent(QMouseEvent * event)
+{
+       // If the left button isn't pressed anymore then return
+       if (!(event->buttons() & Qt::LeftButton))
+               return;
+       
+       // If the distance is too small then return
+       if ((event->pos() - dragStartPos_).manhattanLength()
+           < QApplication::startDragDistance())
+               return;
+
+       // did we hit something after all?
+       int tab = tabAt(dragStartPos_);
+       if (tab == -1)
+               return;
+       
+       // simulate button release to remove highlight from button
+       int i = currentIndex();
+       QMouseEvent me(QEvent::MouseButtonRelease, dragStartPos_,
+               event->button(), event->buttons(), 0);
+       QTabBar::mouseReleaseEvent(&me);
+       setCurrentIndex(i);
+       
+       // initiate Drag
+       QDrag * drag = new QDrag(this);
+       QMimeData * mimeData = new QMimeData;
+       // a crude way to distinguish tab-reodering drops from other ones
+       mimeData->setData("action", "tab-reordering") ;
+       drag->setMimeData(mimeData);
+       
+#if QT_VERSION >= 0x040300
+       // get tab pixmap as cursor
+       QRect r = tabRect(tab);
+       QPixmap pixmap(r.size());
+       render(&pixmap, - r.topLeft());
+       drag->setPixmap(pixmap);
+       drag->exec();
+#else
+       drag->start(Qt::MoveAction);
+#endif
+       
+}
+
+
+void DragTabBar::dragEnterEvent(QDragEnterEvent * event)
+{
+       // Only accept if it's an tab-reordering request
+       QMimeData const * m = event->mimeData();
+       QStringList formats = m->formats();
+       if (formats.contains("action") 
+           && m->data("action") == "tab-reordering")
+               event->acceptProposedAction();
+}
+
+
+void DragTabBar::dropEvent(QDropEvent * event)
+{
+       int fromIndex = tabAt(dragStartPos_);
+       int toIndex = tabAt(event->pos());
+       
+       // Tell interested objects that 
+       if (fromIndex != toIndex)
+               tabMoveRequested(fromIndex, toIndex);
+       event->acceptProposedAction();
+}
+
+
 } // namespace frontend
 } // namespace lyx