annotate widgets/Pane.cpp @ 77:fd348f36c0d3

* Implement harmonic cursor in spectrogram
* Implement layer export.  This doesn't quite do the right thing for the SV
  XML layer export yet -- it doesn't include layer display information, so
  when imported, it only creates an invisible model.  Could also do with
  fixing CSV file import so as to work correctly for note and text layers.

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 Chris Cannam.
    
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#include "widgets/Pane.h"
#include "base/Layer.h"
#include "base/Model.h"
#include "base/ZoomConstraint.h"
#include "base/RealTime.h"
#include "base/Profiler.h"
#include "base/ViewManager.h"
#include "layer/WaveformLayer.h"

#include <QPaintEvent>
#include <QPainter>
#include <iostream>
#include <cmath>

using std::cerr;
using std::endl;

Pane::Pane(QWidget *w) :
    View(w, true),
    m_identifyFeatures(false),
    m_clickedInRange(false),
    m_shiftPressed(false),
    m_ctrlPressed(false),
    m_navigating(false),
    m_resizing(false),
    m_centreLineVisible(true)
{
    setObjectName("Pane");
    setMouseTracking(true);
}

bool
Pane::shouldIlluminateLocalFeatures(const Layer *layer, QPoint &pos) const
{
    QPoint discard;
    bool b0, b1;

    if (layer == getSelectedLayer() &&
	!shouldIlluminateLocalSelection(discard, b0, b1)) {

	pos = m_identifyPoint;
	return m_identifyFeatures;
    }

    return false;
}

bool
Pane::shouldIlluminateLocalSelection(QPoint &pos,
				     bool &closeToLeft,
				     bool &closeToRight) const
{
    if (m_identifyFeatures &&
	m_manager &&
	m_manager->getToolMode() == ViewManager::EditMode &&
	!m_manager->getSelections().empty() &&
	!selectionIsBeingEdited()) {

	Selection s(getSelectionAt(m_identifyPoint.x(),
				   closeToLeft, closeToRight));

	if (!s.isEmpty()) {
	    if (getSelectedLayer() && getSelectedLayer()->isLayerEditable()) {
		
		pos = m_identifyPoint;
		return true;
	    }
	}
    }

    return false;
}

bool
Pane::selectionIsBeingEdited() const
{
    if (!m_editingSelection.isEmpty()) {
	if (m_mousePos != m_clickPos &&
	    getFrameForX(m_mousePos.x()) != getFrameForX(m_clickPos.x())) {
	    return true;
	}
    }
    return false;
}

void
Pane::setCentreLineVisible(bool visible)
{
    m_centreLineVisible = visible;
    update();
}

void
Pane::paintEvent(QPaintEvent *e)
{
    QPainter paint;

    QRect r(rect());

    if (e) {
	r = e->rect();
    }
/*
    paint.begin(this);
    paint.setClipRect(r);

    if (hasLightBackground()) {
	paint.setPen(Qt::white);
	paint.setBrush(Qt::white);
    } else {
	paint.setPen(Qt::black);
	paint.setBrush(Qt::black);
    }
    paint.drawRect(r);

    paint.end();
*/
    View::paintEvent(e);

    paint.begin(this);

    if (e) {
	paint.setClipRect(r);
    }

    const Model *waveformModel = 0; // just for reporting purposes
    int verticalScaleWidth = 0;
    
    int fontHeight = paint.fontMetrics().height();
    int fontAscent = paint.fontMetrics().ascent();

    for (LayerList::iterator vi = m_layers.end(); vi != m_layers.begin(); ) {
        --vi;
            
        if (dynamic_cast<WaveformLayer *>(*vi)) {
            waveformModel = (*vi)->getModel();
        }

        if (m_manager &&
            !m_manager->isPlaying() &&
            m_manager->getToolMode() == ViewManager::SelectMode) {

            std::vector<QRect> crosshairExtents;

            if ((*vi)->getCrosshairExtents(this, paint, m_identifyPoint,
                                           crosshairExtents)) {
                (*vi)->paintCrosshairs(this, paint, m_identifyPoint);
            }
        }

        if (!m_manager ||
            m_manager->getOverlayMode() == ViewManager::NoOverlays) {
            break;
        }

        verticalScaleWidth = (*vi)->getVerticalScaleWidth(this, paint);

        if (verticalScaleWidth > 0 && r.left() < verticalScaleWidth) {

//	    Profiler profiler("Pane::paintEvent - painting vertical scale", true);

//	    std::cerr << "Pane::paintEvent: calling paint.save() in vertical scale block" << std::endl;
            paint.save();
            
            paint.setPen(Qt::black);
            paint.setBrush(Qt::white);
            paint.drawRect(0, -1, verticalScaleWidth, height()+1);
            
            paint.setBrush(Qt::NoBrush);
            (*vi)->paintVerticalScale
                (this, paint, QRect(0, 0, verticalScaleWidth, height()));
            
            paint.restore();
        }
	
        if (m_identifyFeatures) {
            
            QPoint pos = m_identifyPoint;
            QString desc = (*vi)->getFeatureDescription(this, pos);
	    
            if (desc != "") {
                
                paint.save();
                
                int tabStop =
                    paint.fontMetrics().width(tr("Some lengthy prefix:"));
                
                QRect boundingRect = 
                    paint.fontMetrics().boundingRect
                    (rect(),
                     Qt::AlignRight | Qt::AlignTop | Qt::TextExpandTabs,
                     desc, tabStop);

                if (hasLightBackground()) {
                    paint.setPen(Qt::NoPen);
                    paint.setBrush(QColor(250, 250, 250, 200));
                } else {
                    paint.setPen(Qt::NoPen);
                    paint.setBrush(QColor(50, 50, 50, 200));
                }

                int extra = paint.fontMetrics().descent();
                paint.drawRect(width() - boundingRect.width() - 10 - extra,
                               10 - extra,
                               boundingRect.width() + 2 * extra,
                               boundingRect.height() + extra);

                if (hasLightBackground()) {
                    paint.setPen(QColor(150, 20, 0));
                } else {
                    paint.setPen(QColor(255, 150, 100));
                }
		
                QTextOption option;
                option.setWrapMode(QTextOption::NoWrap);
                option.setAlignment(Qt::AlignRight | Qt::AlignTop);
                option.setTabStop(tabStop);
                paint.drawText(QRectF(width() - boundingRect.width() - 10, 10,
                                      boundingRect.width(),
                                      boundingRect.height()),
                               desc,
                               option);

                paint.restore();
            }
        }

        break;
    }
    
    int sampleRate = getModelsSampleRate();
    paint.setBrush(Qt::NoBrush);

    if (m_centreLineVisible) {

	if (hasLightBackground()) {
	    paint.setPen(QColor(50, 50, 50));
	} else {
	    paint.setPen(QColor(200, 200, 200));
	}	
	paint.drawLine(width() / 2, 0, width() / 2, height() - 1);

	paint.setPen(QColor(50, 50, 50));

	int y = height() - fontHeight
	    + fontAscent - 6;
	
	LayerList::iterator vi = m_layers.end();
	
	if (vi != m_layers.begin()) {
	    
	    switch ((*--vi)->getPreferredFrameCountPosition()) {
		
	    case Layer::PositionTop:
		y = fontAscent + 6;
		break;
		
	    case Layer::PositionMiddle:
		y = (height() - fontHeight) / 2
		    + fontAscent;
		break;

	    case Layer::PositionBottom:
		// y already set correctly
		break;
	    }
	}

        if (m_manager &&
            m_manager->getOverlayMode() != ViewManager::NoOverlays) {

            if (sampleRate) {

                QString text(QString::fromStdString
                             (RealTime::frame2RealTime
                              (m_centreFrame, sampleRate).toText(true)));
                
                int tw = paint.fontMetrics().width(text);
                int x = width()/2 - 4 - tw;
                
                drawVisibleText(paint, x, y, text, OutlinedText);
            }
            
            QString text = QString("%1").arg(m_centreFrame);
            
            int tw = paint.fontMetrics().width(text);
            int x = width()/2 + 4;
            
            drawVisibleText(paint, x, y, text, OutlinedText);
        }

    } else {

	paint.setPen(QColor(50, 50, 50));
    }

    if (waveformModel &&
        m_manager &&
        m_manager->getOverlayMode() != ViewManager::NoOverlays &&
	r.y() + r.height() >= height() - fontHeight - 6) {

	size_t mainModelRate = m_manager->getMainModelSampleRate();
	size_t playbackRate = m_manager->getPlaybackSampleRate();
	    
	QString srNote = "";

	// Show (R) for waveform models that will be resampled on
	// playback, and (X) for waveform models that will be played
	// at the wrong rate because their rate differs from that of
	// the main model.

	if (sampleRate == mainModelRate) {
	    if (sampleRate != playbackRate) srNote = " " + tr("(R)");
	} else {
	    std::cerr << "Sample rate = " << sampleRate << ", main model rate = " << mainModelRate << std::endl;
	    srNote = " " + tr("(X)");
	}

	QString desc = tr("%1 / %2Hz%3")
	    .arg(RealTime::frame2RealTime(waveformModel->getEndFrame(),
					  sampleRate)
		 .toText(false).c_str())
	    .arg(sampleRate)
	    .arg(srNote);

	if (r.x() < verticalScaleWidth + 5 + paint.fontMetrics().width(desc)) {
	    drawVisibleText(paint, verticalScaleWidth + 5,
			    height() - fontHeight + fontAscent - 6,
			    desc, OutlinedText);
	}
    }

    if (m_manager &&
        m_manager->getOverlayMode() == ViewManager::AllOverlays &&
        r.y() + r.height() >= height() - m_layers.size() * fontHeight - 6) {

	std::vector<QString> texts;
	int maxTextWidth = 0;

	for (LayerList::iterator i = m_layers.begin(); i != m_layers.end(); ++i) {

	    QString text = (*i)->getLayerPresentationName();
	    int tw = paint.fontMetrics().width(text);
            bool reduced = false;
            while (tw > width() / 3 && text.length() > 4) {
                if (!reduced && text.length() > 8) {
                    text = text.left(text.length() - 4);
                } else {
                    text = text.left(text.length() - 2);
                }
                reduced = true;
                tw = paint.fontMetrics().width(text + "...");
            }
            if (reduced) {
                texts.push_back(text + "...");
            } else {
                texts.push_back(text);
            }
	    if (tw > maxTextWidth) maxTextWidth = tw;
	}
    
	int lly = height() - 6;

	if (r.x() + r.width() >= width() - maxTextWidth - 5) {
	    
	    for (int i = 0; i < texts.size(); ++i) {

		if (i == texts.size() - 1) {
		    paint.setPen(Qt::black);
		}
		
		drawVisibleText(paint, width() - maxTextWidth - 5,
				lly - fontHeight + fontAscent,
				texts[i], OutlinedText);
		
		lly -= fontHeight;
	    }
	}
    }

    if (m_clickedInRange && m_shiftPressed) {
	if (m_manager && (m_manager->getToolMode() == ViewManager::NavigateMode)) {
	    //!!! be nice if this looked a bit more in keeping with the
	    //selection block
	    paint.setPen(Qt::blue);
	    paint.drawRect(m_clickPos.x(), m_clickPos.y(),
			   m_mousePos.x() - m_clickPos.x(),
			   m_mousePos.y() - m_clickPos.y());
	}
    }
    
    if (selectionIsBeingEdited()) {

	int offset = m_mousePos.x() - m_clickPos.x();
	int p0 = getXForFrame(m_editingSelection.getStartFrame()) + offset;
	int p1 = getXForFrame(m_editingSelection.getEndFrame()) + offset;

	if (m_editingSelectionEdge < 0) {
	    p1 = getXForFrame(m_editingSelection.getEndFrame());
	} else if (m_editingSelectionEdge > 0) {
	    p0 = getXForFrame(m_editingSelection.getStartFrame());
	}

	paint.save();
	if (hasLightBackground()) {
	    paint.setPen(QPen(Qt::black, 2));
	} else {
	    paint.setPen(QPen(Qt::white, 2));
	}

	//!!! duplicating display policy with View::drawSelections

	if (m_editingSelectionEdge < 0) {
	    paint.drawLine(p0, 1, p1, 1);
	    paint.drawLine(p0, 0, p0, height());
	    paint.drawLine(p0, height() - 1, p1, height() - 1);
	} else if (m_editingSelectionEdge > 0) {
	    paint.drawLine(p0, 1, p1, 1);
	    paint.drawLine(p1, 0, p1, height());
	    paint.drawLine(p0, height() - 1, p1, height() - 1);
	} else {
	    paint.setBrush(Qt::NoBrush);
	    paint.drawRect(p0, 1, p1 - p0, height() - 2);
	}
	paint.restore();
    }

    paint.end();
}

Selection
Pane::getSelectionAt(int x, bool &closeToLeftEdge, bool &closeToRightEdge) const
{
    closeToLeftEdge = closeToRightEdge = false;

    if (!m_manager) return Selection();

    long testFrame = getFrameForX(x - 5);
    if (testFrame < 0) {
	testFrame = getFrameForX(x);
	if (testFrame < 0) return Selection();
    }

    Selection selection = m_manager->getContainingSelection(testFrame, true);
    if (selection.isEmpty()) return selection;

    int lx = getXForFrame(selection.getStartFrame());
    int rx = getXForFrame(selection.getEndFrame());
    
    int fuzz = 2;
    if (x < lx - fuzz || x > rx + fuzz) return Selection();

    int width = rx - lx;
    fuzz = 3;
    if (width < 12) fuzz = width / 4;
    if (fuzz < 1) fuzz = 1;

    if (x < lx + fuzz) closeToLeftEdge = true;
    if (x > rx - fuzz) closeToRightEdge = true;

    return selection;
}

void
Pane::mousePressEvent(QMouseEvent *e)
{
    m_clickPos = e->pos();
    m_clickedInRange = true;
    m_editingSelection = Selection();
    m_editingSelectionEdge = 0;
    m_shiftPressed = (e->modifiers() & Qt::ShiftModifier);
    m_ctrlPressed = (e->modifiers() & Qt::ControlModifier);

    ViewManager::ToolMode mode = ViewManager::NavigateMode;
    if (m_manager) mode = m_manager->getToolMode();

    m_navigating = false;

    if (mode == ViewManager::NavigateMode || (e->buttons() & Qt::MidButton)) {

	if (mode != ViewManager::NavigateMode) {
	    setCursor(Qt::PointingHandCursor);
	}

	m_navigating = true;
	m_dragCentreFrame = m_centreFrame;

    } else if (mode == ViewManager::SelectMode) {

	bool closeToLeft = false, closeToRight = false;
	Selection selection = getSelectionAt(e->x(), closeToLeft, closeToRight);

	if ((closeToLeft || closeToRight) && !(closeToLeft && closeToRight)) {

	    m_manager->removeSelection(selection);

	    if (closeToLeft) {
		m_selectionStartFrame = selection.getEndFrame();
	    } else {
		m_selectionStartFrame = selection.getStartFrame();
	    }

	    m_manager->setInProgressSelection(selection, false);
	    m_resizing = true;
	
	} else {

	    int mouseFrame = getFrameForX(e->x());
	    size_t resolution = 1;
	    int snapFrame = mouseFrame;
	
	    Layer *layer = getSelectedLayer();
	    if (layer) {
		layer->snapToFeatureFrame(this, snapFrame,
					  resolution, Layer::SnapLeft);
	    }
	    
	    if (snapFrame < 0) snapFrame = 0;
	    m_selectionStartFrame = snapFrame;
	    if (m_manager) {
		m_manager->setInProgressSelection(Selection(snapFrame,
							    snapFrame + resolution),
						  !m_ctrlPressed);
	    }

	    m_resizing = false;
	}

	update();

    } else if (mode == ViewManager::DrawMode) {

	Layer *layer = getSelectedLayer();
	if (layer && layer->isLayerEditable()) {
	    layer->drawStart(this, e);
	}

    } else if (mode == ViewManager::EditMode) {

	if (!editSelectionStart(e)) {
	    Layer *layer = getSelectedLayer();
	    if (layer && layer->isLayerEditable()) {
		layer->editStart(this, e);
	    }
	}
    }

    emit paneInteractedWith();
}

void
Pane::mouseReleaseEvent(QMouseEvent *e)
{
    ViewManager::ToolMode mode = ViewManager::NavigateMode;
    if (m_manager) mode = m_manager->getToolMode();

    if (m_clickedInRange) {
	mouseMoveEvent(e);
    }

    if (m_navigating || mode == ViewManager::NavigateMode) {

	m_navigating = false;

	if (mode != ViewManager::NavigateMode) {
	    // restore cursor
	    toolModeChanged();
	}

	if (m_shiftPressed) {

	    int x0 = std::min(m_clickPos.x(), m_mousePos.x());
	    int x1 = std::max(m_clickPos.x(), m_mousePos.x());
	    int w = x1 - x0;
	    
	    long newStartFrame = getFrameForX(x0);
	    
	    long visibleFrames = getEndFrame() - getStartFrame();
	    if (newStartFrame <= -visibleFrames) {
		newStartFrame  = -visibleFrames + 1;
	    }
	    
	    if (newStartFrame >= long(getModelsEndFrame())) {
		newStartFrame  = getModelsEndFrame() - 1;
	    }
	    
	    float ratio = float(w) / float(width());
//	std::cerr << "ratio: " << ratio << std::endl;
	    size_t newZoomLevel = (size_t)nearbyint(m_zoomLevel * ratio);
	    if (newZoomLevel < 1) newZoomLevel = 1;

//	std::cerr << "start: " << m_startFrame << ", level " << m_zoomLevel << std::endl;
	    setZoomLevel(getZoomConstraintBlockSize(newZoomLevel));
	    setStartFrame(newStartFrame);

	    //cerr << "mouseReleaseEvent: start frame now " << m_startFrame << endl;
//	update();
	}

    } else if (mode == ViewManager::SelectMode) {

	if (m_manager && m_manager->haveInProgressSelection()) {

	    bool exclusive;
	    Selection selection = m_manager->getInProgressSelection(exclusive);
	    
	    if (selection.getEndFrame() < selection.getStartFrame() + 2) {
		selection = Selection();
	    }
	    
	    m_manager->clearInProgressSelection();
	    
	    if (exclusive) {
		m_manager->setSelection(selection);
	    } else {
		m_manager->addSelection(selection);
	    }
	}
	
	update();

    } else if (mode == ViewManager::DrawMode) {

	Layer *layer = getSelectedLayer();
	if (layer && layer->isLayerEditable()) {
	    layer->drawEnd(this, e);
	    update();
	}

    } else if (mode == ViewManager::EditMode) {

	if (!editSelectionEnd(e)) {
	    Layer *layer = getSelectedLayer();
	    if (layer && layer->isLayerEditable()) {
		layer->editEnd(this, e);
		update();
	    }
	}
    }

    m_clickedInRange = false;

    emit paneInteractedWith();
}

void
Pane::mouseMoveEvent(QMouseEvent *e)
{
    ViewManager::ToolMode mode = ViewManager::NavigateMode;
    if (m_manager) mode = m_manager->getToolMode();

    QPoint prevPoint = m_identifyPoint;
    m_identifyPoint = e->pos();

    if (!m_clickedInRange) {
	
	if (mode == ViewManager::SelectMode) {
	    bool closeToLeft = false, closeToRight = false;
	    getSelectionAt(e->x(), closeToLeft, closeToRight);
	    if ((closeToLeft || closeToRight) && !(closeToLeft && closeToRight)) {
		setCursor(Qt::SizeHorCursor);
	    } else {
		setCursor(Qt::ArrowCursor);
	    }
	}

//!!!	if (mode != ViewManager::DrawMode) {

        if (!m_manager->isPlaying()) {

	if (getSelectedLayer()) {

	    bool previouslyIdentifying = m_identifyFeatures;
	    m_identifyFeatures = true;
	    
	    if (m_identifyFeatures != previouslyIdentifying ||
		m_identifyPoint != prevPoint) {
		update();
	    }
	}

        }

//	}

	return;
    }

    if (m_navigating || mode == ViewManager::NavigateMode) {

	if (m_shiftPressed) {

	    m_mousePos = e->pos();
	    update();

	} else {

	    long frameOff = getFrameForX(e->x()) - getFrameForX(m_clickPos.x());

	    size_t newCentreFrame = m_dragCentreFrame;
	    
	    if (frameOff < 0) {
		newCentreFrame -= frameOff;
	    } else if (newCentreFrame >= size_t(frameOff)) {
		newCentreFrame -= frameOff;
	    } else {
		newCentreFrame = 0;
	    }
	    
	    if (newCentreFrame >= getModelsEndFrame()) {
		newCentreFrame = getModelsEndFrame();
		if (newCentreFrame > 0) --newCentreFrame;
	    }

	    if (getXForFrame(m_centreFrame) != getXForFrame(newCentreFrame)) {
		setCentreFrame(newCentreFrame);
	    }
	}

    } else if (mode == ViewManager::SelectMode) {

	int mouseFrame = getFrameForX(e->x());
	size_t resolution = 1;
	int snapFrameLeft = mouseFrame;
	int snapFrameRight = mouseFrame;
	
	Layer *layer = getSelectedLayer();
	if (layer) {
	    layer->snapToFeatureFrame(this, snapFrameLeft,
				      resolution, Layer::SnapLeft);
	    layer->snapToFeatureFrame(this, snapFrameRight,
				      resolution, Layer::SnapRight);
	}
	
//	std::cerr << "snap: frame = " << mouseFrame << ", start frame = " << m_selectionStartFrame << ", left = " << snapFrameLeft << ", right = " << snapFrameRight << std::endl;

	if (snapFrameLeft < 0) snapFrameLeft = 0;
	if (snapFrameRight < 0) snapFrameRight = 0;
	
	size_t min, max;
	
	if (m_selectionStartFrame > snapFrameLeft) {
	    min = snapFrameLeft;
	    max = m_selectionStartFrame;
	} else if (snapFrameRight > m_selectionStartFrame) {
	    min = m_selectionStartFrame;
	    max = snapFrameRight;
	} else {
	    min = snapFrameLeft;
	    max = snapFrameRight;
	}

	if (m_manager) {
	    m_manager->setInProgressSelection(Selection(min, max),
					      !m_resizing && !m_ctrlPressed);
	}

	bool doScroll = false;
	if (!m_manager) doScroll = true;
	if (!m_manager->isPlaying()) doScroll = true;
	if (m_followPlay != PlaybackScrollContinuous) doScroll = true;

	if (doScroll) {
	    int offset = mouseFrame - getStartFrame();
	    int available = getEndFrame() - getStartFrame();
	    if (offset >= available * 0.95) {
		int move = int(offset - available * 0.95) + 1;
		setCentreFrame(m_centreFrame + move);
	    } else if (offset <= available * 0.10) {
		int move = int(available * 0.10 - offset) + 1;
		if (m_centreFrame > move) {
		    setCentreFrame(m_centreFrame - move);
		} else {
		    setCentreFrame(0);
		}
	    }
	}

	update();

    } else if (mode == ViewManager::DrawMode) {

	Layer *layer = getSelectedLayer();
	if (layer && layer->isLayerEditable()) {
	    layer->drawDrag(this, e);
	}

    } else if (mode == ViewManager::EditMode) {

	if (!editSelectionDrag(e)) {
	    Layer *layer = getSelectedLayer();
	    if (layer && layer->isLayerEditable()) {
		layer->editDrag(this, e);
	    }
	}
    }
}

void
Pane::mouseDoubleClickEvent(QMouseEvent *e)
{
    std::cerr << "mouseDoubleClickEvent" << std::endl;

    m_clickPos = e->pos();
    m_clickedInRange = true;
    m_shiftPressed = (e->modifiers() & Qt::ShiftModifier);
    m_ctrlPressed = (e->modifiers() & Qt::ControlModifier);

    ViewManager::ToolMode mode = ViewManager::NavigateMode;
    if (m_manager) mode = m_manager->getToolMode();

    if (mode == ViewManager::EditMode) {

	Layer *layer = getSelectedLayer();
	if (layer && layer->isLayerEditable()) {
	    layer->editOpen(this, e);
	}
    }
}

void
Pane::leaveEvent(QEvent *)
{
    bool previouslyIdentifying = m_identifyFeatures;
    m_identifyFeatures = false;
    if (previouslyIdentifying) update();
}

void
Pane::wheelEvent(QWheelEvent *e)
{
    //std::cerr << "wheelEvent, delta " << e->delta() << std::endl;

    int count = e->delta();

    if (count > 0) {
	if (count >= 120) count /= 120;
	else count = 1;
    } 

    if (count < 0) {
	if (count <= -120) count /= 120;
	else count = -1;
    }

    if (e->modifiers() & Qt::ControlModifier) {

	// Scroll left or right, rapidly

	if (getStartFrame() < 0 && 
	    getEndFrame() >= getModelsEndFrame()) return;

	long delta = ((width() / 2) * count * m_zoomLevel);

	if (int(m_centreFrame) < delta) {
	    setCentreFrame(0);
	} else if (int(m_centreFrame) - delta >= int(getModelsEndFrame())) {
	    setCentreFrame(getModelsEndFrame());
	} else {
	    setCentreFrame(m_centreFrame - delta);
	}

    } else {

	// Zoom in or out

	int newZoomLevel = m_zoomLevel;
  
	while (count > 0) {
	    if (newZoomLevel <= 2) {
		newZoomLevel = 1;
		break;
	    }
	    newZoomLevel = getZoomConstraintBlockSize(newZoomLevel - 1, 
						      ZoomConstraint::RoundDown);
	    --count;
	}
	
	while (count < 0) {
	    newZoomLevel = getZoomConstraintBlockSize(newZoomLevel + 1,
						      ZoomConstraint::RoundUp);
	    ++count;
	}
	
	if (newZoomLevel != m_zoomLevel) {
	    setZoomLevel(newZoomLevel);
	}
    }

    emit paneInteractedWith();
}

bool
Pane::editSelectionStart(QMouseEvent *e)
{
    if (!m_identifyFeatures ||
	!m_manager ||
	m_manager->getToolMode() != ViewManager::EditMode) {
	return false;
    }

    bool closeToLeft, closeToRight;
    Selection s(getSelectionAt(e->x(), closeToLeft, closeToRight));
    if (s.isEmpty()) return false;
    m_editingSelection = s;
    m_editingSelectionEdge = (closeToLeft ? -1 : closeToRight ? 1 : 0);
    m_mousePos = e->pos();
    return true;
}

bool
Pane::editSelectionDrag(QMouseEvent *e)
{
    if (m_editingSelection.isEmpty()) return false;
    m_mousePos = e->pos();
    update();
    return true;
}

bool
Pane::editSelectionEnd(QMouseEvent *e)
{
    if (m_editingSelection.isEmpty()) return false;

    int offset = m_mousePos.x() - m_clickPos.x();
    Layer *layer = getSelectedLayer();

    if (offset == 0 || !layer) {
	m_editingSelection = Selection();
	return true;
    }

    int p0 = getXForFrame(m_editingSelection.getStartFrame()) + offset;
    int p1 = getXForFrame(m_editingSelection.getEndFrame()) + offset;

    long f0 = getFrameForX(p0);
    long f1 = getFrameForX(p1);

    Selection newSelection(f0, f1);
    
    if (m_editingSelectionEdge == 0) {
	
	layer->moveSelection(m_editingSelection, f0);
	
    } else {
	
	if (m_editingSelectionEdge < 0) {
	    f1 = m_editingSelection.getEndFrame();
	} else {
	    f0 = m_editingSelection.getStartFrame();
	}

	newSelection = Selection(f0, f1);
	layer->resizeSelection(m_editingSelection, newSelection);
    }
    
    m_manager->removeSelection(m_editingSelection);
    m_manager->addSelection(newSelection);

    m_editingSelection = Selection();
    return true;
}

void
Pane::toolModeChanged()
{
    ViewManager::ToolMode mode = m_manager->getToolMode();
    std::cerr << "Pane::toolModeChanged(" << mode << ")" << std::endl;

    switch (mode) {

    case ViewManager::NavigateMode:
	setCursor(Qt::PointingHandCursor);
	break;
	
    case ViewManager::SelectMode:
	setCursor(Qt::ArrowCursor);
	break;
	
    case ViewManager::EditMode:
	setCursor(Qt::UpArrowCursor);
	break;
	
    case ViewManager::DrawMode:
	setCursor(Qt::CrossCursor);
	break;
/*	
    case ViewManager::TextMode:
	setCursor(Qt::IBeamCursor);
	break;
*/
    }
}

QString
Pane::toXmlString(QString indent, QString extraAttributes) const
{
    return View::toXmlString
	(indent,
	 QString("type=\"pane\" centreLineVisible=\"%1\" height=\"%2\" %3")
	 .arg(m_centreLineVisible).arg(height()).arg(extraAttributes));
}


#ifdef INCLUDE_MOCFILES
#include "Pane.moc.cpp"
#endif