Manually adjust geometry in custom widget

[Rooster]

I have a subclassed widget that I paint on. What I want to do is is click on a zoom in button and have the widget expand horizontally. Right now what happens is I click on zoom in and the widget stays the same size. Here is a snippet of what I am currently doing with the resizing.

Chart::Chart(QWidget *parent) : QWidget(parent)
{
  setSizePolicy ( QSizePolicy::Expanding, QSizePolicy::Expanding);
  setGeometry(0,0,base_width,base_height);
}
 
Chart::set_resize(int w, int h)
{
  QSize size(w,h);
  resize(size);
}

Chart::Chart(QWidget *parent) : QWidget(parent)
{
  setSizePolicy ( QSizePolicy::Expanding, QSizePolicy::Expanding);
  setGeometry(0,0,base_width,base_height);
}

Chart::set_resize(int w, int h)
{
  QSize size(w,h);
  resize(size);
}

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What am I doing wrong?
Any suggestions?

Thank You