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# canvas.cpp Example File
graphicsview/portedcanvas/canvas.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2006-2006 Trolltech ASA. All rights reserved.
    **
    ** This file is part of the example classes of the Qt Toolkit.
    **
    ** Licensees holding valid Qt Preview licenses may use this file in
    ** accordance with the Qt Preview License Agreement provided with the
    ** Software.
    **
    ** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
    ** information about Qt Commercial License Agreements.
    **
    ** Contact info@trolltech.com if any conditions of this licensing are
    ** not clear to you.
    **
    ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
    ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
    **
    ****************************************************************************/

    #include <qdatetime.h>
    #include <qmainwindow.h>
    #include <qstatusbar.h>
    #include <qmessagebox.h>
    #include <qmenubar.h>
    #include <qapplication.h>
    #include <qpainter.h>
    #include <qprinter.h>
    #include <qlabel.h>
    #include <qimage.h>
    #include <q3progressdialog.h>
    #include <Q3PointArray>
    #include <Q3PtrList>
    #include <QPixmap>
    #include <Q3PopupMenu>
    #include <QMouseEvent>
    #include <Q3MemArray>
    #include "canvas.h"
    #include <QStyleOptionGraphicsItem>
    #include <qdebug.h>
    #include <stdlib.h>

    // We use a global variable to save memory - all the brushes and pens in
    // the mesh are shared.
    static QBrush *tb = 0;
    static QPen *tp = 0;

    class EdgeItem;
    class NodeItem;

    class EdgeItem: public QGraphicsLineItem
    {
    public:
        EdgeItem( NodeItem*, NodeItem* );
        void setFromPoint( int x, int y ) ;
        void setToPoint( int x, int y );
        static int count() { return c; }
    private:
        static int c;
    };

    static const int imageRTTI = 984376;

    class ImageItem: public QGraphicsRectItem
    {
    public:
        ImageItem( QImage img );
        int rtti () const { return imageRTTI; }
    protected:
        void paint( QPainter *, const QStyleOptionGraphicsItem *option, QWidget *widget );
    private:
        QImage image;
        QPixmap pixmap;
    };

    ImageItem::ImageItem( QImage img )
        : image(img)
    {
        setRect(0, 0, image.width(), image.height());
        setFlag(ItemIsMovable);
    #if !defined(Q_WS_QWS)
        pixmap.convertFromImage(image, Qt::OrderedAlphaDither);
    #endif
    }

    void ImageItem::paint( QPainter *p, const QStyleOptionGraphicsItem *option, QWidget * )
    {
    // On Qt/Embedded, we can paint a QImage as fast as a QPixmap,
    // but on other platforms, we need to use a QPixmap.
    #if defined(Q_WS_QWS)
        p->drawImage( option->exposedRect, image, option->exposedRect, Qt::OrderedAlphaDither );
    #else
        p->drawPixmap( option->exposedRect, pixmap, option->exposedRect );
    #endif
    }

    class NodeItem: public QGraphicsEllipseItem
    {
    public:
        NodeItem();
        ~NodeItem() {}

        void addInEdge( EdgeItem *edge ) { inList.append( edge ); }
        void addOutEdge( EdgeItem *edge ) { outList.append( edge ); }

    protected:
        QVariant itemChange(GraphicsItemChange change, const QVariant &value);

        //    QPoint center() { return boundingRect().center(); }
    private:
        Q3PtrList<EdgeItem> inList;
        Q3PtrList<EdgeItem> outList;
    };

    int EdgeItem::c = 0;

    EdgeItem::EdgeItem( NodeItem *from, NodeItem *to )
        : QGraphicsLineItem( )
    {
        c++;
        setPen( *tp );
        from->addOutEdge( this );
        to->addInEdge( this );
        setLine( QLineF(int(from->x()), int(from->y()), int(to->x()), int(to->y()) ));
        setZValue( 127 );
    }

    void EdgeItem::setFromPoint( int x, int y )
    {
        setLine(QLineF( x,y, line().p2().x(), line().p2().y() ));
    }

    void EdgeItem::setToPoint( int x, int y )
    {
        setLine(QLineF( line().p1().x(), line().p1().y(), x, y ));
    }

    QVariant NodeItem::itemChange(GraphicsItemChange change, const QVariant &value)
    {
        if (change == ItemPositionChange) {
            Q3PtrListIterator<EdgeItem> it1( inList );
            EdgeItem *edge;
            while (( edge = it1.current() )) {
                ++it1;
                edge->setToPoint( int(x()), int(y()) );
            }
            Q3PtrListIterator<EdgeItem> it2( outList );
            while (( edge = it2.current() )) {
                ++it2;
                edge->setFromPoint( int(x()), int(y()) );
            }
        }

        return QGraphicsEllipseItem::itemChange(change, value);
    }

    NodeItem::NodeItem( )
        : QGraphicsEllipseItem( QRectF(-3, -3, 6, 6) )
    {
        setPen( *tp );
        setBrush( *tb );
        setZValue( 128 );
        setFlag(ItemIsMovable);
    }

    FigureEditor::FigureEditor(
            QGraphicsScene& c, QWidget* parent,
            const char* name, Qt::WindowFlags f) :
        QGraphicsView(&c,parent)
    {
        setObjectName(name);
        setWindowFlags(f);
        setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
    }

    void FigureEditor::clear()
    {
        QList<QGraphicsItem *> list = scene()->items();
        QList<QGraphicsItem *>::Iterator it = list.begin();
        for (; it != list.end(); ++it) {
            if ( *it )
                delete *it;
        }
    }

    BouncyLogo::BouncyLogo() :
        xvel(0), yvel(0)
    {
        setPixmap(QPixmap(":/trolltech/examples/graphicsview/portedcanvas/qt-trans.xpm"));
    }

    const int logo_rtti = 1234;

    int BouncyLogo::type() const
    {
        return logo_rtti;
    }

    QPainterPath BouncyLogo::shape() const
    {
        QPainterPath path;
        path.addRect(boundingRect());
        return path;
    }

    void BouncyLogo::initPos()
    {
        initSpeed();
        int trial=1000;
        do {
            setPos(qrand()%int(scene()->width()),qrand()%int(scene()->height()));
            advance(0);
        } while (trial-- && xvel==0.0 && yvel==0.0);
    }

    void BouncyLogo::initSpeed()
    {
        const double speed = 4.0;
        double d = (double)(qrand()%1024) / 1024.0;
        xvel = d*speed*2-speed;
        yvel = (1-d)*speed*2-speed;
    }

    void BouncyLogo::advance(int stage)
    {
        switch ( stage ) {
          case 0: {
            double vx = xvel;
            double vy = yvel;

            if ( vx == 0.0 && vy == 0.0 ) {
                // stopped last turn
                initSpeed();
                vx = xvel;
                vy = yvel;
            }

            double nx = x() + vx;
            double ny = y() + vy;

            if ( nx < 0 || nx >= scene()->width() )
                vx = -vx;
            if ( ny < 0 || ny >= scene()->height() )
                vy = -vy;

            for (int bounce=0; bounce<4; bounce++) {
                QList<QGraphicsItem *> l=scene()->collidingItems(this);
                for (QList<QGraphicsItem *>::Iterator it=l.begin(); it!=l.end(); ++it) {
                    QGraphicsItem *hit = *it;
                    QPainterPath advancedShape = QMatrix().translate(xvel, yvel).map(shape());
                    if ( hit->type()==logo_rtti && hit->collidesWithPath(mapToItem(hit, advancedShape)) ) {
                        switch ( bounce ) {
                          case 0:
                            vx = -vx;
                            break;
                          case 1:
                            vy = -vy;
                            vx = -vx;
                            break;
                          case 2:
                            vx = -vx;
                            break;
                          case 3:
                            // Stop for this turn
                            vx = 0;
                            vy = 0;
                            break;
                        }
                        xvel = vx;
                        yvel = vy;
                        break;
                    }
                }
            }

            if ( x()+vx < 0 || x()+vx >= scene()->width() )
                vx = 0;
            if ( y()+vy < 0 || y()+vy >= scene()->height() )
                vy = 0;

            xvel = vx;
            yvel = vy;
          } break;
          case 1:
            moveBy(xvel, yvel);
            break;
        }
    }

    static uint mainCount = 0;
    static QImage *butterflyimg;
    static QImage *logoimg;

    Main::Main(QGraphicsScene& c, QWidget* parent, const char* name, Qt::WindowFlags f) :
        Q3MainWindow(parent,name,f),
        canvas(c)
    {
        editor = new FigureEditor(canvas,this);
        QMenuBar* menu = menuBar();

        Q3PopupMenu* file = new Q3PopupMenu( menu );
        file->insertItem("&Fill canvas", this, SLOT(init()), Qt::CTRL+Qt::Key_F);
        file->insertItem("&Erase canvas", this, SLOT(clear()), Qt::CTRL+Qt::Key_E);
        file->insertItem("&New view", this, SLOT(newView()), Qt::CTRL+Qt::Key_N);
        file->insertSeparator();
        file->insertItem("&Print...", this, SLOT(print()), Qt::CTRL+Qt::Key_P);
        file->insertSeparator();
        file->insertItem("E&xit", qApp, SLOT(quit()), Qt::CTRL+Qt::Key_Q);
        menu->insertItem("&File", file);

        Q3PopupMenu* edit = new Q3PopupMenu( menu );
        edit->insertItem("Add &Circle", this, SLOT(addCircle()), Qt::ALT+Qt::Key_C);
        edit->insertItem("Add &Hexagon", this, SLOT(addHexagon()), Qt::ALT+Qt::Key_H);
        edit->insertItem("Add &Polygon", this, SLOT(addPolygon()), Qt::ALT+Qt::Key_P);
        edit->insertItem("Add Spl&ine", this, SLOT(addSpline()), Qt::ALT+Qt::Key_I);
        edit->insertItem("Add &Text", this, SLOT(addText()), Qt::ALT+Qt::Key_T);
        edit->insertItem("Add &Line", this, SLOT(addLine()), Qt::ALT+Qt::Key_L);
        edit->insertItem("Add &Rectangle", this, SLOT(addRectangle()), Qt::ALT+Qt::Key_R);
        edit->insertItem("Add &Sprite", this, SLOT(addSprite()), Qt::ALT+Qt::Key_S);
        edit->insertItem("Create &Mesh", this, SLOT(addMesh()), Qt::ALT+Qt::Key_M );
        edit->insertItem("Add &Alpha-blended image", this, SLOT(addButterfly()), Qt::ALT+Qt::Key_A);
        menu->insertItem("&Edit", edit);

        Q3PopupMenu* view = new Q3PopupMenu( menu );
        view->insertItem("&Enlarge", this, SLOT(enlarge()), Qt::SHIFT+Qt::CTRL+Qt::Key_Plus);
        view->insertItem("Shr&ink", this, SLOT(shrink()), Qt::SHIFT+Qt::CTRL+Qt::Key_Minus);
        view->insertSeparator();
        view->insertItem("&Rotate clockwise", this, SLOT(rotateClockwise()), Qt::CTRL+Qt::Key_PageDown);
        view->insertItem("Rotate &counterclockwise", this, SLOT(rotateCounterClockwise()), Qt::CTRL+Qt::Key_PageUp);
        view->insertItem("&Zoom in", this, SLOT(zoomIn()), Qt::CTRL+Qt::Key_Plus);
        view->insertItem("Zoom &out", this, SLOT(zoomOut()), Qt::CTRL+Qt::Key_Minus);
        view->insertItem("Translate left", this, SLOT(moveL()), Qt::CTRL+Qt::Key_Left);
        view->insertItem("Translate right", this, SLOT(moveR()), Qt::CTRL+Qt::Key_Right);
        view->insertItem("Translate up", this, SLOT(moveU()), Qt::CTRL+Qt::Key_Up);
        view->insertItem("Translate down", this, SLOT(moveD()), Qt::CTRL+Qt::Key_Down);
        view->insertItem("&Mirror", this, SLOT(mirror()), Qt::CTRL+Qt::Key_Home);
        menu->insertItem("&View", view);

        menu->insertSeparator();

        Q3PopupMenu* help = new Q3PopupMenu( menu );
        help->insertItem("&About", this, SLOT(help()), Qt::Key_F1);
        help->setItemChecked(dbf_id, TRUE);
        menu->insertItem("&Help",help);

        statusBar();

        setCentralWidget(editor);

        printer = 0;

        init();
    }

    void Main::init()
    {
        clear();

        static int r=24;
        qsrand(++r);

        mainCount++;
        butterflyimg = 0;
        logoimg = 0;

        int i;
        for ( i=0; i<canvas.width() / 56; i++) {
            addButterfly();
        }
        for ( i=0; i<canvas.width() / 85; i++) {
            addHexagon();
        }
        for ( i=0; i<canvas.width() / 128; i++) {
            addLogo();
        }
    }

    Main::~Main()
    {
        delete printer;
        if ( !--mainCount ) {
            delete[] butterflyimg;
            butterflyimg = 0;
            delete[] logoimg;
            logoimg = 0;
        }
    }

    void Main::newView()
    {
        // Open a new view... have it delete when closed.
        Main *m = new Main(canvas, 0, 0, Qt::WDestructiveClose);
        m->show();
    }

    void Main::clear()
    {
        editor->clear();
    }

    void Main::help()
    {
        static QMessageBox* about = new QMessageBox( "Qt Canvas Example",
                "<h3>The QCanvas classes example</h3>"
                "<ul>"
                    "<li> Press ALT-S for some sprites."
                    "<li> Press ALT-C for some circles."
                    "<li> Press ALT-L for some lines."
                    "<li> Drag the objects around."
                    "<li> Read the code!"
                "</ul>", QMessageBox::Information, 1, 0, 0, this, 0, FALSE );
        about->setButtonText( 1, "Dismiss" );
        about->show();
    }

    void Main::aboutQt()
    {
        QMessageBox::aboutQt( this, "Qt Canvas Example" );
    }

    void Main::enlarge()
    {
        canvas.setSceneRect(0, 0, canvas.width()*4/3, canvas.height()*4/3);
    }

    void Main::shrink()
    {
        canvas.setSceneRect(0, 0, canvas.width()*3/4, canvas.height()*3/4);
    }

    void Main::rotateClockwise()
    {
        editor->rotate( 22.5 );
    }

    void Main::rotateCounterClockwise()
    {
        editor->rotate( -22.5 );
    }

    void Main::zoomIn()
    {
        editor->scale( 2.0, 2.0 );
    }

    void Main::zoomOut()
    {
        editor->scale( 0.5, 0.5 );
    }

    void Main::mirror()
    {
        editor->scale( -1, 1 );
    }

    void Main::moveL()
    {
        editor->translate( -16, 0 );
    }

    void Main::moveR()
    {
        editor->translate( +16, 0 );
    }

    void Main::moveU()
    {
        editor->translate( 0, -16 );
    }

    void Main::moveD()
    {
        editor->translate( 0, +16 );
    }

    void Main::print()
    {
        if ( !printer ) printer = new QPrinter;
        if ( printer->setup(this) ) {
            QPainter pp(printer);
            canvas.render(&pp);
        }
    }

    void Main::addSprite()
    {
        BouncyLogo* i = new BouncyLogo;
        canvas.addItem(i);
        i->initPos();
        i->setZValue(qrand()%256);
    }

    QString butterfly_fn;
    QString logo_fn;

    void Main::addButterfly()
    {
        if ( butterfly_fn.isEmpty() )
            return;
        if ( !butterflyimg ) {
            butterflyimg = new QImage[4];
            butterflyimg[0].load( butterfly_fn );
            butterflyimg[1] = butterflyimg[0].smoothScale( int(butterflyimg[0].width()*0.75),
                    int(butterflyimg[0].height()*0.75) );
            butterflyimg[2] = butterflyimg[0].smoothScale( int(butterflyimg[0].width()*0.5),
                    int(butterflyimg[0].height()*0.5) );
            butterflyimg[3] = butterflyimg[0].smoothScale( int(butterflyimg[0].width()*0.25),
                    int(butterflyimg[0].height()*0.25) );
        }
        QAbstractGraphicsShapeItem* i = new ImageItem(butterflyimg[qrand()%4]);
        canvas.addItem(i);
        i->setPos(qrand()%int(canvas.width()-butterflyimg->width()),
                qrand()%int(canvas.height()-butterflyimg->height()));
        i->setZValue(qrand()%256+250);
    }

    void Main::addLogo()
    {
        if ( logo_fn.isEmpty() )
            return;
        if ( !logoimg ) {
            logoimg = new QImage[4];
            logoimg[0].load( logo_fn );
            logoimg[1] = logoimg[0].smoothScale( int(logoimg[0].width()*0.75),
                    int(logoimg[0].height()*0.75) );
            logoimg[2] = logoimg[0].smoothScale( int(logoimg[0].width()*0.5),
                    int(logoimg[0].height()*0.5) );
            logoimg[3] = logoimg[0].smoothScale( int(logoimg[0].width()*0.25),
                    int(logoimg[0].height()*0.25) );
        }
        QAbstractGraphicsShapeItem* i = new ImageItem(logoimg[qrand()%4]);
        canvas.addItem(i);
        i->setPos(qrand()%int(canvas.width()-logoimg->width()),
                qrand()%int(canvas.height()-logoimg->width()));
        i->setZValue(qrand()%256+256);
    }

    void Main::addCircle()
    {
        QAbstractGraphicsShapeItem* i = canvas.addEllipse(QRectF(0,0,50,50));
        i->setFlag(QGraphicsItem::ItemIsMovable);
        i->setPen(Qt::NoPen);
        i->setBrush( QColor(qrand()%32*8,qrand()%32*8,qrand()%32*8) );
        i->setPos(qrand()%int(canvas.width()),qrand()%int(canvas.height()));
        i->setZValue(qrand()%256);
    }

    void Main::addHexagon()
    {
        const int size = int(canvas.width() / 25);
        Q3PointArray pa(6);
        pa[0] = QPoint(2*size,0);
        pa[1] = QPoint(size,-size*173/100);
        pa[2] = QPoint(-size,-size*173/100);
        pa[3] = QPoint(-2*size,0);
        pa[4] = QPoint(-size,size*173/100);
        pa[5] = QPoint(size,size*173/100);
        QGraphicsPolygonItem* i = canvas.addPolygon(pa);
        i->setFlag(QGraphicsItem::ItemIsMovable);
        i->setPen(Qt::NoPen);
        i->setBrush( QColor(qrand()%32*8,qrand()%32*8,qrand()%32*8) );
        i->setPos(qrand()%int(canvas.width()),qrand()%int(canvas.height()));
        i->setZValue(qrand()%256);
    }

    void Main::addPolygon()
    {
        const int size = int(canvas.width()/2);
        Q3PointArray pa(6);
        pa[0] = QPoint(0,0);
        pa[1] = QPoint(size,size/5);
        pa[2] = QPoint(size*4/5,size);
        pa[3] = QPoint(size/6,size*5/4);
        pa[4] = QPoint(size*3/4,size*3/4);
        pa[5] = QPoint(size*3/4,size/4);
        QGraphicsPolygonItem* i = canvas.addPolygon(pa);
        i->setFlag(QGraphicsItem::ItemIsMovable);
        i->setPen(Qt::NoPen);
        i->setBrush( QColor(qrand()%32*8,qrand()%32*8,qrand()%32*8) );
        i->setPos(qrand()%int(canvas.width()),qrand()%int(canvas.height()));
        i->setZValue(qrand()%256);
    }

    void Main::addSpline()
    {
        const int size = int(canvas.width()/6);

        Q3PointArray pa(12);
        pa[0] = QPoint(0,0);
        pa[1] = QPoint(size/2,0);
        pa[2] = QPoint(size,size/2);
        pa[3] = QPoint(size,size);
        pa[4] = QPoint(size,size*3/2);
        pa[5] = QPoint(size/2,size*2);
        pa[6] = QPoint(0,size*2);
        pa[7] = QPoint(-size/2,size*2);
        pa[8] = QPoint(size/4,size*3/2);
        pa[9] = QPoint(0,size);
        pa[10]= QPoint(-size/4,size/2);
        pa[11]= QPoint(-size/2,0);

        QPainterPath path;
        path.moveTo(pa[0]);
        for (int i = 1; i < pa.size(); i += 3)
            path.cubicTo(pa[i], pa[(i + 1) % pa.size()], pa[(i + 2) % pa.size()]);

        QGraphicsPathItem* item = canvas.addPath(path);
        item->setFlag(QGraphicsItem::ItemIsMovable);
        item->setPen(Qt::NoPen);
        item->setBrush( QColor(qrand()%32*8,qrand()%32*8,qrand()%32*8) );
        item->setPos(qrand()%int(canvas.width()),qrand()%int(canvas.height()));
        item->setZValue(qrand()%256);
    }

    void Main::addText()
    {
        QGraphicsTextItem* i = canvas.addText("QCanvasText");
        i->setFlag(QGraphicsItem::ItemIsMovable);
        i->setPos(qrand()%int(canvas.width()),qrand()%int(canvas.height()));
        i->setZValue(qrand()%256);
    }

    void Main::addLine()
    {
        QGraphicsLineItem* i = canvas.addLine(QLineF( qrand()%int(canvas.width()), qrand()%int(canvas.height()),
                                                      qrand()%int(canvas.width()), qrand()%int(canvas.height()) ));
        i->setFlag(QGraphicsItem::ItemIsMovable);
        i->setPen( QPen(QColor(qrand()%32*8,qrand()%32*8,qrand()%32*8), 6) );
        i->setZValue(qrand()%256);
    }

    void Main::addMesh()
    {
        int x0 = 0;
        int y0 = 0;

        if ( !tb ) tb = new QBrush( Qt::red );
        if ( !tp ) tp = new QPen( Qt::black );

        int nodecount = 0;

        int w = int(canvas.width());
        int h = int(canvas.height());

        const int dist = 30;
        int rows = h / dist;
        int cols = w / dist;

    #ifndef QT_NO_PROGRESSDIALOG
        Q3ProgressDialog progress( "Creating mesh...", "Abort", rows,
                                  this, "progress", TRUE );
    #endif

        Q3MemArray<NodeItem*> lastRow(cols);
        for ( int j = 0; j < rows; j++ ) {
            int n = j%2 ? cols-1 : cols;
            NodeItem *prev = 0;
            for ( int i = 0; i < n; i++ ) {
                NodeItem *el = new NodeItem;
                canvas.addItem(el);
                nodecount++;
                int r = qrand();
                int xrand = r %20;
                int yrand = (r/20) %20;
                el->setPos( xrand + x0 + i*dist + (j%2 ? dist/2 : 0 ),
                            yrand + y0 + j*dist );

                if ( j > 0 ) {
                    if ( i < cols-1 )
                        canvas.addItem(new EdgeItem( lastRow[i], el));
                    if ( j%2 )
                        canvas.addItem(new EdgeItem( lastRow[i+1], el));
                    else if ( i > 0 )
                        canvas.addItem(new EdgeItem( lastRow[i-1], el));
                }
                if ( prev ) {
                    canvas.addItem(new EdgeItem( prev, el));
                }
                if ( i > 0 ) lastRow[i-1] = prev;
                prev = el;
            }
            lastRow[n-1]=prev;
    #ifndef QT_NO_PROGRESSDIALOG
            progress.setProgress( j );
            if ( progress.wasCancelled() )
                break;
    #endif
        }
    #ifndef QT_NO_PROGRESSDIALOG
        progress.setProgress( rows );
    #endif
        // qDebug( "%d nodes, %d edges", nodecount, EdgeItem::count() );
    }

    void Main::addRectangle()
    {
        QAbstractGraphicsShapeItem *i = canvas.addRect( QRectF(qrand()%int(canvas.width()),
                                                              qrand()%int(canvas.height()),
                                                              canvas.width()/5,
                                                              canvas.width()/5) );
        i->setFlag(QGraphicsItem::ItemIsMovable);
        int z = qrand()%256;
        i->setBrush( QColor(z,z,z) );
        i->setPen( QPen(QColor(qrand()%32*8,qrand()%32*8,qrand()%32*8), 6) );
        i->setZValue(z);
    }