canvas.cpp Example File
graphicsview/portedcanvas/canvas.cpp
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#include <QDateTime>
#include <QMainWindow>
#include <QStatusBar>
#include <QMessageBox>
#include <QMenuBar>
#include <QApplication>
#include <QPainter>
#include <QPrinter>
#include <QPrintDialog>
#include <QLabel>
#include <QImage>
#include <QProgressDialog>
#include <QPixmap>
#include <QMouseEvent>
#include <QStyleOptionGraphicsItem>
#include <QDebug>
#include "canvas.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;
};
class ImageItem: public QGraphicsRectItem
{
public:
ImageItem( QImage img );
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.fromImage(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:
QList<EdgeItem*> inList;
QList<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 );
setBoundingRegionGranularity(0.05);
}
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 == ItemPositionHasChanged) {
EdgeItem *edge;
foreach(edge, inList) {
edge->setToPoint( int(x()), int(y()) );
}
foreach(edge, outList) {
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()
{
scene()->clear();
}
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, Qt::WindowFlags f) :
QMainWindow(parent, f),
canvas(c)
{
editor = new FigureEditor(canvas,this);
QMenuBar* menu = menuBar();
QMenu* file = new QMenu("&File", menu );
file->addAction("&Fill canvas", this, SLOT(init()), Qt::CTRL+Qt::Key_F);
file->addAction("&Erase canvas", this, SLOT(clear()), Qt::CTRL+Qt::Key_E);
file->addAction("&New view", this, SLOT(newView()), Qt::CTRL+Qt::Key_N);
file->addSeparator();
file->addAction("&Print...", this, SLOT(print()), Qt::CTRL+Qt::Key_P);
file->addSeparator();
file->addAction("E&xit", qApp, SLOT(quit()), Qt::CTRL+Qt::Key_Q);
menu->addMenu(file);
QMenu* edit = new QMenu("&Edit", menu );
edit->addAction("Add &Circle", this, SLOT(addCircle()), Qt::ALT+Qt::Key_C);
edit->addAction("Add &Hexagon", this, SLOT(addHexagon()), Qt::ALT+Qt::Key_H);
edit->addAction("Add &Polygon", this, SLOT(addPolygon()), Qt::ALT+Qt::Key_P);
edit->addAction("Add Spl&ine", this, SLOT(addSpline()), Qt::ALT+Qt::Key_I);
edit->addAction("Add &Text", this, SLOT(addText()), Qt::ALT+Qt::Key_T);
edit->addAction("Add &Line", this, SLOT(addLine()), Qt::ALT+Qt::Key_L);
edit->addAction("Add &Rectangle", this, SLOT(addRectangle()), Qt::ALT+Qt::Key_R);
edit->addAction("Add &Sprite", this, SLOT(addSprite()), Qt::ALT+Qt::Key_S);
edit->addAction("Create &Mesh", this, SLOT(addMesh()), Qt::ALT+Qt::Key_M );
edit->addAction("Add &Alpha-blended image", this, SLOT(addButterfly()), Qt::ALT+Qt::Key_A);
menu->addMenu(edit);
QMenu* view = new QMenu("&View", menu );
view->addAction("&Enlarge", this, SLOT(enlarge()), Qt::SHIFT+Qt::CTRL+Qt::Key_Plus);
view->addAction("Shr&ink", this, SLOT(shrink()), Qt::SHIFT+Qt::CTRL+Qt::Key_Minus);
view->addSeparator();
view->addAction("&Rotate clockwise", this, SLOT(rotateClockwise()), Qt::CTRL+Qt::Key_PageDown);
view->addAction("Rotate &counterclockwise", this, SLOT(rotateCounterClockwise()), Qt::CTRL+Qt::Key_PageUp);
view->addAction("&Zoom in", this, SLOT(zoomIn()), Qt::CTRL+Qt::Key_Plus);
view->addAction("Zoom &out", this, SLOT(zoomOut()), Qt::CTRL+Qt::Key_Minus);
view->addAction("Translate left", this, SLOT(moveL()), Qt::CTRL+Qt::Key_Left);
view->addAction("Translate right", this, SLOT(moveR()), Qt::CTRL+Qt::Key_Right);
view->addAction("Translate up", this, SLOT(moveU()), Qt::CTRL+Qt::Key_Up);
view->addAction("Translate down", this, SLOT(moveD()), Qt::CTRL+Qt::Key_Down);
view->addAction("&Mirror", this, SLOT(mirror()), Qt::CTRL+Qt::Key_Home);
menu->addMenu(view);
menu->addSeparator();
QMenu* help = new QMenu("&Help", menu );
help->addAction("&About", this, SLOT(help()), Qt::Key_F1);
menu->addMenu(help);
statusBar();
setCentralWidget(editor);
#if !defined(Q_OS_SYMBIAN)
printer = 0;
#endif
init();
}
void Main::init()
{
clear();
static int r=24;
qsrand(++r);
mainCount++;
butterflyimg = 0;
logoimg = 0;
int i;
for ( i=0; i < int(canvas.width()) / 56; i++) {
addButterfly();
}
for ( i=0; i < int(canvas.width()) / 85; i++) {
addHexagon();
}
for ( i=0; i < int(canvas.width()) / 128; i++) {
addLogo();
}
}
Main::~Main()
{
#if !defined(Q_OS_SYMBIAN)
delete printer;
#endif
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); // AKr, Qt::WA_DeleteOnClose);
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);
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, qMax(canvas.width()*3/4, qreal(1.0)), qMax(canvas.height()*3/4, qreal(1.0)));
}
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 !defined(Q_OS_SYMBIAN)
if ( !printer ) printer = new QPrinter;
QPrintDialog dialog(printer, this);
if(dialog.exec()) {
QPainter pp(printer);
canvas.render(&pp);
}
#endif
}
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].scaled( int(butterflyimg[0].width()*0.75),
int(butterflyimg[0].height()*0.75), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
butterflyimg[2] = butterflyimg[0].scaled( int(butterflyimg[0].width()*0.5),
int(butterflyimg[0].height()*0.5), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
butterflyimg[3] = butterflyimg[0].scaled( int(butterflyimg[0].width()*0.25),
int(butterflyimg[0].height()*0.25), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
}
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].scaled( int(logoimg[0].width()*0.75),
int(logoimg[0].height()*0.75), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
logoimg[2] = logoimg[0].scaled( int(logoimg[0].width()*0.5),
int(logoimg[0].height()*0.5), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
logoimg[3] = logoimg[0].scaled( int(logoimg[0].width()*0.25),
int(logoimg[0].height()*0.25), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
}
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);
QPolygon polygon;
polygon << QPoint(2*size,0)
<< QPoint(size,-size*173/100)
<< QPoint(-size,-size*173/100)
<< QPoint(-2*size,0)
<< QPoint(-size,size*173/100)
<< QPoint(size,size*173/100);
QGraphicsPolygonItem* i = canvas.addPolygon(polygon);
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);
QPolygon polygon;
polygon << QPoint(0,0)
<< QPoint(size,size/5)
<< QPoint(size*4/5,size)
<< QPoint(size/6,size*5/4)
<< QPoint(size*3/4,size*3/4)
<< QPoint(size*3/4,size/4);
QGraphicsPolygonItem* i = canvas.addPolygon(polygon);
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);
QPolygon polygon;
polygon << QPoint(0,0)
<< QPoint(size/2,0)
<< QPoint(size,size/2)
<< QPoint(size,size)
<< QPoint(size,size*3/2)
<< QPoint(size/2,size*2)
<< QPoint(0,size*2)
<< QPoint(-size/2,size*2)
<< QPoint(size/4,size*3/2)
<< QPoint(0,size)
<< QPoint(-size/4,size/2)
<< QPoint(-size/2,0);
QPainterPath path;
path.moveTo(polygon[0]);
for (int i = 1; i < polygon.size(); i += 3)
path.cubicTo(polygon[i], polygon[(i + 1) % polygon.size()], polygon[(i + 2) % polygon.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
QProgressDialog progress("Creating mesh...", "Abort", 0, rows, this);
#endif
canvas.update();
QVector<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.setValue( j );
if ( progress.wasCanceled() )
break;
#endif
}
#ifndef QT_NO_PROGRESSDIALOG
progress.setValue( 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);
}
