view panner.cpp @ 109:1721c580c10e

* Add a queueing mechanism for Hg actions, instead of refusing to start an action if something else is already happening.  This is essential now that actions can be prompted by asynchronous events (e.g. filesystem watcher).
 * Make Revert behave sensibly

/* -*- 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) 2010 Chris Cannam
    Copyright (c) 2010 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 <QPolygon>
#include <QMouseEvent>
#include <QColor>

#include <iostream>

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

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

void
Panner::setScene(QGraphicsScene *s)
{
    if (scene()) {
        disconnect(scene(), SIGNAL(sceneRectChanged(const QRectF &)),
                   this, SLOT(slotSceneRectChanged(const QRectF &)));
    }
    QGraphicsView::setScene(s);
    if (scene()) fitInView(sceneRect(), Qt::IgnoreAspectRatio);
    m_cache = QPixmap();
    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 *)
{
    if (scene()) fitInView(sceneRect(), Qt::IgnoreAspectRatio);
    m_cache = QPixmap();
}

void
Panner::slotSceneRectChanged(const QRectF &newRect)
{
    if (!scene()) return; // spurious
    fitInView(newRect, Qt::IgnoreAspectRatio);
    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)
{
    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()) {

    std::cerr << "Panner: recreating cache" << std::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();
    }

    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_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;
    QRectF nr = m_clickedRect;
    nr.translate(delta);
    slotSetPannedRect(nr);
    emit pannedRectChanged(m_pannedRect);
    viewport()->update();
}

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

    if (m_clicked) {
        mouseMoveEvent(e);
    }

    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 d = sp.x() - nr.center().x();
    nr.translate(d, 0);
    slotSetPannedRect(nr);
    emit pannedRectChanged(m_pannedRect);
    viewport()->update();
}