QT Drawing Tutorial 3:qt Basic Drawing

1. Drawing graphics
[CPP]View Plain copy protected:void paintevent (qpaintevent *); void Widget::p aintevent ((qpaintevent *event) {qpainter painter (this);//this as a drawing device, that is, drawing on the part Painter.draw   Line (qpaint (0, 0), Qpaint (100, 100)); } qpainter painter (this); Will immediately begin drawing on the device, call the Begin () function automatically, and then call the end () function in the destructor to finish drawing.
Qpainter painter;//without parameters, you can call Qpainter::begin (Qpaintdevice *device) later to specify the drawing settings, and then call the end () function when you are finished.

Equivalent to
[CPP]View plain copy void Widget::p aintevent ((qpaintevent *event) {qpainter painter;       Painter.begin (this);       Painter.drawline (qpaint (0, 0), Qpaint (100, 100));   Painter.end (); } 2. Using Paint brushes
Paint brush to set color and fill modes
[CPP]View Plain copy Qbrush brush (Qcolor (0,0,255), Qt::D ense4pattern);   Painter.setbrush (brush); 3. Using brushes
[CPP]View plain copy//parameters are: Paint brush, line width, brush style, draw nib Point, brush connection style Qpen pen (qt::green, 5, Qt::D otline, Qt::roundcap, Qt::roundjoin);   Painter.setpen (pen); 4. Draw a Rectangle
[CPP]View Plain copy painter.drawrect (0, 0, 100, 80); X,y,w,h 5. Draw Ellipse (circle)
[CPP]View Plain copy painter.drawellipse (0, 0, 100, 80); X,y,w,h 6. Drawing arcs
[CPP]View Plain copy QRECTF rect (70.0, 40.0, 80.0, 60.0); X,y,w,h