draw a point

[Malek]

Starting /home/MALEK/soso-build-desktop/soso...
QPainter::begin: Paint device returned engine == 0, type: 2
QPainter::setRenderHint: Painter must be active to set rendering hints
QPainter::save: Painter not active
QPainter::setClipRect: Painter not active
QPainter::setWorldTransform: Painter not active
QPainter::worldTransform: Painter not active
QPainter::save: Painter not active
QPainter::setWorldTransform: Painter not active
QPainter::setOpacity: Painter not active
QPainter::setPen: Painter not active
QPainter::setBrush: Painter not active
QPainter::drawRects: Painter not active
QPainter::restore: Unbalanced save/restore
QPainter::setWorldTransform: Painter not active
QPainter::restore: Unbalanced save/restore
QPainter::end: Painter not active, aborted
/home/MALEK/soso-build-desktop/soso exited with code 0

Even When I use the code of the tutorial this msgs appears !!

I use this code

QGraphicsScene scene;
 scene.addRect(QRectF(0, 0, 100, 200), QPen(Qt::black), QBrush(Qt::green));
 
 QPixmap pixmap;
 QPainter painter(&pixmap);
 painter.setRenderHint(QPainter::Antialiasing);
 scene.render(&painter);
 painter.end();
 
 pixmap.save("scene.png");

QGraphicsScene scene;
 scene.addRect(QRectF(0, 0, 100, 200), QPen(Qt::black), QBrush(Qt::green));

 QPixmap pixmap;
 QPainter painter(&pixmap);
 painter.setRenderHint(QPainter::Antialiasing);
 scene.render(&painter);
 painter.end();

 pixmap.save("scene.png");

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from this link:
http://doc.qt.nokia.com/4.6/graphicsview.html

[Malek]

It is very simple issue.I just draw it like this

QPen pen;
   pen.color().blue();
   QGraphicsScene *scene = new QGraphicsScene();
   scene->addEllipse(QRectF(0,0 ,10 ,10 ), pen, QBrush(Qt::red));
   ui->graphicsView->setScene(scene);

QPen pen;
   pen.color().blue();
   QGraphicsScene *scene = new QGraphicsScene();
   scene->addEllipse(QRectF(0,0 ,10 ,10 ), pen, QBrush(Qt::red));
   ui->graphicsView->setScene(scene);

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NOW !!!
You MUST help me in this.

1) I want to change the point location. It is always in the same location even when I replace (0,0 ,10,10) by (168,324,10,10) for example.

2) How can I change the location of the point as (Lat, Lon),Since my background will be the map of the WORLD.


THANKS FOR ALL.

[Malek]

911 !!
Help me please !!

[norobro]

1) I want to change the point location. It is always in the same location even when I replace (0,0 ,10,10) by (168,324,10,10) for example.

From the docs: "Note that the item's geometry is provided in item coordinates, and its position is initialized to (0, 0)." If you only have one item on your scene it will always be in the same location. Try adding two ellipse items.

2) How can I change the location of the point as (Lat, Lon),Since my background will be the map of the WORLD.

Try something like this:

QGraphicsScene scene;
QPixmap pixmap("/path/to/worldmap.jpg");
scene.addPixmap(pixmap);
scene.addEllipse(QRectF(168,324,10,10),QPen(Qt::red),QBrush(Qt::red));
QGraphicsView view(&scene);
view.show();

QGraphicsScene scene;
QPixmap pixmap("/path/to/worldmap.jpg");
scene.addPixmap(pixmap);
scene.addEllipse(QRectF(168,324,10,10),QPen(Qt::red),QBrush(Qt::red));
QGraphicsView view(&scene);
view.show();

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You'll have to handle translating lat/long to scene coordinates.