How to pan Image inside PictureBox

Question

I have a custom PictureBox which can zoom in using MouseWheel event. Now I want to add a panning feature to it. I mean when PictureBox is in zoomed

Answer 1

I think the math is backwards. Try it like this:

private Point startingPoint = Point.Empty;
private Point movingPoint = Point.Empty;
private bool panning = false;

void pictureBox1_MouseDown(object sender, MouseEventArgs e) {
  panning = true;
  startingPoint = new Point(e.Location.X - movingPoint.X,
                            e.Location.Y - movingPoint.Y);
}

void pictureBox1_MouseUp(object sender, MouseEventArgs e) {
  panning = false;
}

void pictureBox1_MouseMove(object sender, MouseEventArgs e) {
  if (panning) {
    movingPoint = new Point(e.Location.X - startingPoint.X, 
                            e.Location.Y - startingPoint.Y);
    pictureBox1.Invalidate();
  }
}

void pictureBox1_Paint(object sender, PaintEventArgs e) {
  e.Graphics.Clear(Color.White);
  e.Graphics.DrawImage(Image, movingPoint);
}

You aren't disposing your graphic object, and CreateGraphics is just a temporary drawing anyway (minimizing would erase it) so I moved the drawing code to the Paint event and am just invalidating as the user is panning.