void graphics::paintEvent(QPaintEvent *){ QPainter painter(this); if(mode == 2) HinhTron(painter); if(mode == 3) HinhVuong(painter); if(mode == 4) {HinhTron(painter); HinhVuong(painter);} if(mode == 5) HinhTC(painter); if(mode == 6) Venha(painter);}

void graphics::HinhTron(QPainter& painter){

painter.setPen(Qt::green); int w,h; w=width(); h=height(); QPoint A(w/2,h/2); painter.drawEllipse(A,100,100);}void graphics::HinhVuong(QPainter& painter){ painter.setPen(Qt::blue); int w,h; float x,y; w=width(); h=height(); x=w/2-50*sqrt(2); y=h/2-50*sqrt(2);

painter.drawRect(x,y,200/sqrt(2),200/sqrt(2));}void graphics::HinhTC(QPainter& painter){ painter.setPen(Qt::red); int w,h; w=width(); h=height(); QPoint A(w/2,h/2); painter.drawEllipse(A,100,100); QPoint B(w/2+50,h/2); QPoint C(w/2-50,h/2); painter.drawEllipse(B,10,10); painter.drawEllipse(C,10,10); painter.drawArc(w/2-100,h/2-50,100,100,0,-180*16); painter.drawArc(w/2,h/2-50,100,100,0,180*16);

}void graphics::Venha(QPainter& painter){ painter.setPen(Qt::blue); int w,h; w=width(); h=height(); QPolygon nha; nha<<QPoint(100,200)<<QPoint(200,200)<<QPoint(200,100)<<QPoint(150,50)<<QPoint(100,100); painter.drawPolygon(nha); QPolygon cuachinh; cuachinh<<QPoint(125,200)<<QPoint(125,160)<<QPoint(150,160)<<QPoint(150,200); painter.drawPolyline(cuachinh); QPolygon cuaso;

cuaso<<QPoint(160,140)<<QPoint(180,140)<<QPoint(180,120)<<QPoint(160,120); painter.drawPolygon(cuaso); QPolygon ongkhoi; ongkhoi<<QPoint(110,90)<<QPoint(110,50)<<QPoint(120,50)<<QPoint(120,80); painter.drawPolyline(ongkhoi);

}