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
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.