protected override void OnMouseLeave(EventArgs e)
{
/* Called when the mouse leaves the GridBox altogether.
* We must reset the colour of the last active square
* to its own BackColor.
*
* We don't need to handle a specific MouseEnter() event for the GridBox
* because the MouseMove handler will already pick it up. */
if (ActiveSquare != null)
{
ActiveSquare.OnMouseLeave();
ActiveSquare = null;
}
}
protected override void OnMouseMove(MouseEventArgs e)
{
/* We have to check the position of the mouse on the grid (in pixels),
* and obtain the Square object which resides in that position.
* If that square is not also the currently set ActiveSquare,
* it means that we've left the previously active square, and we
* have to reset its colour to its own BackColor. */
Square squareObj = GetSquare(e.X, e.Y);
if (squareObj == null)
{
// No such square. We must be out of bounds.
Console.WriteLine("MouseMove error. No such square. Out of bounds.");
return;
}
if (squareObj != ActiveSquare)
{
/* Either ActiveSquare is null, or there's a previously active square.
* In the case of a previously active on, we must call OnMouseLeave() on it.
* We also have to call OnMouseEnter() on the new square. */
if (ActiveSquare != null)
{
// There is a previously active square
ActiveSquare.OnMouseLeave();
ActiveSquare = squareObj;
}
/* Call OnMouseEnter() on the newly entered square.
* We do this here to avoid calling OnMouseEnter()
* whenever the mouse moves inside the square
* after having already entered its area.
*
* However, before calling OnMouseEnter(), we must check whether
* one of the mouse buttons is currently pressed.
* If it's pressed, it means that the square is caught in a mouse drag,
* and therefore should be notified that this is happening. */
if (LeftMouseDown)
{
squareObj.MouseEvent = MouseEventType.LeftButtonDrag;
}
else if (RightMouseDown)
{
squareObj.MouseEvent = MouseEventType.RightButtonDrag;
}
squareObj.OnMouseEnter();
}
// Set our current square object as the active square
ActiveSquare = squareObj;
}