protected override void OnMouseUp(MouseEventArgs e)
{
if (Capture && e.Button == MouseButtons.Left)
{
// If the mouse is captured and it's the Left button being released, the user is
// done creating a new Ellipse.
// Stop capturing the mouse.
Capture = false;
// Final update of the Ellipse under construction
UpdateEllipseUnderConstruction(e.Location);
// Add the new Ellipse to our list unless its width or height are zero which would result in a non-visible ellipse
if (ellipseConstruction.Ellipse.Rectangle.Width > 0 && ellipseConstruction.Ellipse.Rectangle.Height > 0)
{
ellipses.Add(ellipseConstruction.Ellipse);
}
// Since we are done constructing a new Ellipse, we don't need the construction object
ellipseConstruction = null;
}
base.OnMouseUp(e);
}
protected override void OnKeyDown(KeyEventArgs e)
{
// Allow Ellipse creation to be cancelled with the Escape key
if (Capture && e.KeyData == Keys.Escape)
{
Capture = false; // End mouse capture
ellipseConstruction = null; // Remove construction ellipse
Invalidate(); // Notify operating system that we need to be repainted.
}
base.OnKeyDown(e);
}
protected override void OnMouseDown(MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
// Capture mouse until button up.
Capture = true;
// Create a new Ellipse object and record the [X, Y] origin of this click
ellipseConstruction = new EllipseConstruction
{
Origin = e.Location,
Ellipse = new Ellipse {
Color = EllipseColors[Rand.Next(EllipseColors.Length)], PenWidth = Rand.Next(1, 6)
},
};
}
base.OnMouseDown(e);
}
