view src/panner.cpp @ 571:012ba1b83328

Show cancel button with progress bar only when running an operation that it makes sense to cancel (we don't really want people cancelling e.g. initial folder scan because it would leave things in an inconsistent state)

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

/*
    EasyMercurial

    Based on HgExplorer by Jari Korhonen
    Copyright (c) 2010 Jari Korhonen
    Copyright (c) 2012 Chris Cannam
    Copyright (c) 2012 Queen Mary, University of London
    
    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 "panner.h"
#include "panned.h"
#include "debug.h"

#include <QPolygon>
#include <QMouseEvent>
#include <QColor>

#include <iostream>

class PannerScene : public QGraphicsScene
{
public:
    friend class Panner;
};

Panner::Panner() :
    m_clicked(false),
    m_moved(false)
{
    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setOptimizationFlags(QGraphicsView::DontSavePainterState |
                         QGraphicsView::IndirectPainting);
    setMouseTracking(true);
    setInteractive(false);
}

void
Panner::fit(QRectF r)
{
    Qt::AspectRatioMode m = Qt::IgnoreAspectRatio;
    if (height() > width()) {
        // Our panner is vertical; if the source is not tall,
        // don't stretch it to fit in the height, it'd look weird
        if (r.height() < height() * 2) {
            m = Qt::KeepAspectRatio;
        }
    } else {
        // Similarly, but horizontal
        if (r.width() < width() * 2) {
            m = Qt::KeepAspectRatio;
        }
    }
    DEBUG << "Panner: fit mode " << m << endl;
    fitInView(r, m);
}

void
Panner::setScene(QGraphicsScene *s)
{
    if (scene()) {
        disconnect(scene(), SIGNAL(changed(const QList<QRectF> &)),
                   this, SLOT(slotSceneChanged(const QList<QRectF> &)));
        disconnect(scene(), SIGNAL(sceneRectChanged(const QRectF &)),
                   this, SLOT(slotSceneRectChanged(const QRectF &)));
    }
    QGraphicsView::setScene(s);
    m_cache = QPixmap();
    if (scene()) {
        QRectF r = sceneRect();
        DEBUG << "scene rect: " << r << ", my rect " << rect() << endl;
        fit(r);
        connect(scene(), SIGNAL(changed(const QList<QRectF> &)),
                this, SLOT(slotSceneChanged(const QList<QRectF> &)));
        connect(scene(), SIGNAL(sceneRectChanged(const QRectF &)),
                this, SLOT(slotSceneRectChanged(const QRectF &)));
    }
}

void
Panner::connectToPanned(Panned *p)
{
    connect(p, SIGNAL(pannedRectChanged(QRectF)),
            this, SLOT(slotSetPannedRect(QRectF)));

    connect(this, SIGNAL(pannedRectChanged(QRectF)),
            p, SLOT(slotSetPannedRect(QRectF)));

    connect(this, SIGNAL(zoomIn()),
            p, SLOT(zoomIn()));

    connect(this, SIGNAL(zoomOut()),
            p, SLOT(zoomOut()));
}

void
Panner::slotSetPannedRect(QRectF rect) 
{
    m_pannedRect = rect;
    viewport()->update();
}

void
Panner::resizeEvent(QResizeEvent *)
{
    DEBUG << "Panner::resizeEvent" << endl;
    if (scene()) fit(sceneRect());
    m_cache = QPixmap();
}

void
Panner::slotSceneRectChanged(const QRectF &newRect)
{
    DEBUG << "Panner::slotSceneRectChanged" << endl;
    if (!scene()) return; // spurious
    fit(newRect);
    m_cache = QPixmap();
    viewport()->update();
}

void
Panner::slotSceneChanged(const QList<QRectF> &)
{
    DEBUG << "Panner::slotSceneChanged" << endl;
    if (!scene()) return; // spurious
    m_cache = QPixmap();
    viewport()->update();
}

void
Panner::paintEvent(QPaintEvent *e)
{
    QPaintEvent *e2 = new QPaintEvent(e->region().boundingRect());
    QGraphicsView::paintEvent(e2);

    QPainter paint;
    paint.begin(viewport());
    paint.setClipRegion(e->region());

    QPainterPath path;
    path.addRect(rect());
    path.addPolygon(mapFromScene(m_pannedRect));

    QColor c(QColor::fromHsv(211, 194, 238));
    c.setAlpha(80);
    paint.setPen(Qt::NoPen);
    paint.setBrush(c);
    paint.drawPath(path);

    paint.setBrush(Qt::NoBrush);
    paint.setPen(QPen(QColor::fromHsv(211, 194, 238), 0));
    paint.drawConvexPolygon(mapFromScene(m_pannedRect));

    paint.end();

    emit pannerChanged(m_pannedRect);
}

void
Panner::updateScene(const QList<QRectF> &rects)
{
    DEBUG << "Panner::updateScene" << endl;
//    if (!m_cache.isNull()) m_cache = QPixmap();
    QGraphicsView::updateScene(rects);
}

void
Panner::drawItems(QPainter *painter, int numItems,
                  QGraphicsItem *items[],
                  const QStyleOptionGraphicsItem options[])
{
    if (m_cache.size() != viewport()->size()) {

        DEBUG << "Panner: cache size " << m_cache.size() << " != viewport size " << viewport()->size() << ": recreating cache" << endl;

        QGraphicsScene *s = scene();
        if (!s) return;
        PannerScene *ps = static_cast<PannerScene *>(s);

        m_cache = QPixmap(viewport()->size());
        m_cache.fill(Qt::transparent);
        QPainter cachePainter;
        cachePainter.begin(&m_cache);
        cachePainter.setTransform(viewportTransform());
        ps->drawItems(&cachePainter, numItems, items, options);
        cachePainter.end();

        DEBUG << "done" << endl;
    }

    painter->save();
    painter->setTransform(QTransform());
    painter->drawPixmap(0, 0, m_cache);
    painter->restore();
}
 
void
Panner::mousePressEvent(QMouseEvent *e)
{
    if (e->button() != Qt::LeftButton) {
        QGraphicsView::mouseDoubleClickEvent(e);
        return;
    }
    m_clicked = true;
    m_moved = false;
    m_clickedRect = m_pannedRect;
    m_clickedPoint = e->pos();
}

void
Panner::mouseDoubleClickEvent(QMouseEvent *e)
{
    if (e->button() != Qt::LeftButton) {
        QGraphicsView::mouseDoubleClickEvent(e);
        return;
    }

    moveTo(e->pos());
}

void
Panner::mouseMoveEvent(QMouseEvent *e)
{
    if (!m_clicked) return;
    QPointF cp = mapToScene(m_clickedPoint);
    QPointF mp = mapToScene(e->pos());
    QPointF delta = mp - cp;
    if (!m_moved) {
        if ((m_clickedPoint - e->pos()).manhattanLength() > 2) {
            m_moved = true;
        } else {
            return;
        }
    }
    QRectF nr = m_clickedRect;
    nr.translate(delta);
    m_pannedRect = nr;
    emit pannedRectChanged(m_pannedRect);
    viewport()->update();
}

void
Panner::mouseReleaseEvent(QMouseEvent *e)
{
    if (e->button() != Qt::LeftButton) {
        QGraphicsView::mouseDoubleClickEvent(e);
        return;
    }

    if (m_clicked) {
        if (m_moved) {
            mouseMoveEvent(e);
        } else {
            moveTo(e->pos());
        }
    }

    m_clicked = false;
    viewport()->update();
}

void
Panner::wheelEvent(QWheelEvent *e)
{
    int d = e->delta();
    if (d > 0) {
        while (d > 0) {
            emit zoomOut();
            d -= 120;
        }
    } else {
        while (d < 0) {
            emit zoomIn();
            d += 120;
        }
    }
}

void
Panner::moveTo(QPoint p)
{
    QPointF sp = mapToScene(p);
    QRectF nr = m_pannedRect;
    double dx = sp.x() - nr.center().x();
    double dy = sp.y() - nr.center().y();
    nr.translate(dx, dy);
    slotSetPannedRect(nr);
    emit pannedRectChanged(m_pannedRect);
    viewport()->update();
}