Question

I am writing an application in C++ with QT where you have n points and compute the convex hull of this. However, once this is computed I have no idea how to plot the points and draw the border of the hull. Making menu buttons and such is simple enough, but I’m not sure I know the tools to do this.

How do you do this?

Answer 1

You can just create a custom class deriving from QWidget where you override the void paintEvent(QPaintEvent* event) method. In that you put the points into some sort of point list, either std::vector<QPoint> or QList<QPoint> and then paint it with a Polyline method. For instance:

void Foo::paintEvent(QPaintEvent* event)
{
  QPainter painter(this);
  std::vector<QPoint> points;
  // Fill points with the points
  painter.drawPolyLine(points.data(), static_cast<int>(points.size()));
}