draw a curve on qt

[ramy]

Hi,

I'm trying to draw an helix on a qt dialog or widget but it's not working!

here are the parametric equations of an helix in 2d.

x=30*cos(2*pi*t)
y=t;

that's what i have written so far in the paintEvent function
but the curve does not appear;

void MainWindow::paintEvent(QPaintEvent *){
QPainter paint(this);
for(qreal i=0;i<2*M_PI;i=i+0.1){
y=+300*cos(i); // I know that i did not use the same values that i have written above, i don't care about the values as long
QPoint T(y,i); // as i can draw a random helix!
polygon.push_back(T);
}
paint.drawPolygon(polygon);

}



PS: i don't want to use a graph. Actually i'm trying to draw a spring i need it for a project i'm working on

Thanks For your help :)

[anda_skoa]

Have you checked that the values you are generating are within the visible range?

0 <= x <= width()
0 <= y <= height()

Cheers,
_

[ramy]

Thanks anda_skoa, but i have found the problem!

[d_stranz]

but i have found the problem!

The purpose of this forum is not just to ask questions, but to also give your solution when you get something working. Telling the world that "I solved it" isn't very helpful to the rest of the forum readers who don't know what you did wrong.