private void OwnedForm_Resizing(object sender, ResizeEventArgs e)
{
if (m_snapGrid != null)
{
m_snapGrid.SnapWhileResizing(e, ref m_rectangleBeforeSizeMove, MaxSnapDistance, InsensitiveBorderEndLength);
}
}
private void MdiChild_Resizing(object sender, ResizeEventArgs e)
{
if (m_snapGrid != null)
{
// Check if the MDI client rectangle changed during move/resize, because the client area may show or hide scrollbars during sizing/moving of the window.
CheckUpdateSizeMove();
m_snapGrid.SnapWhileResizing(e, ref m_rectangleBeforeSizeMove, MaxSnapDistance, InsensitiveBorderEndLength);
}
}
protected override void WndProc(ref Message m)
{
if (m.Msg == WM.SIZING)
{
// Marshal the size/move rectangle from the message.
RECT rc = (RECT)Marshal.PtrToStructure(m.LParam, typeof(RECT));
var e = new ResizeEventArgs(rc, (ResizeMode)m.WParam.ToInt32());
OnResizing(e);
// Marshal back the result.
Marshal.StructureToPtr(e.MoveResizeRect, m.LParam, true);
}
else if (m.Msg == WM.MOVING)
{
// Marshal the size/move rectangle from the message.
RECT rc = (RECT)Marshal.PtrToStructure(m.LParam, typeof(RECT));
// Add displacement resulting from continuous updates by OnMoving().
rc.Left += m_displacement.X;
rc.Top += m_displacement.Y;
rc.Right += m_displacement.X;
rc.Bottom += m_displacement.Y;
var e = new MoveResizeEventArgs(rc);
OnMoving(e);
// Calculate new displacement for the next WndProc() iteration.
m_displacement.X = rc.Left - e.MoveResizeRect.Left;
m_displacement.Y = rc.Top - e.MoveResizeRect.Top;
// Marshal back the result.
Marshal.StructureToPtr(e.MoveResizeRect, m.LParam, true);
}
base.WndProc(ref m);
}
/// <summary>
/// Modifies a <see cref="ResizeEventArgs"/> so a window will snap to segments
/// defined in this <see cref="SnapGrid"/> while it's being resized.
/// </summary>
/// <param name="e">
/// The <see cref="ResizeEventArgs"/> to modify.
/// </param>
/// <param name="rectangleBeforeSizeMove">
/// The bounds of the rectangle of the window before it was being resized.
/// </param>
/// <param name="maxSnapDistance">
/// The maximum distance from a line segment within which the window will snap to a line segment.
/// </param>
/// <param name="cutoff">
/// The length to cut off both ends of line segments representing the edges of the window being resized.
/// </param>
public void SnapWhileResizing(ResizeEventArgs e, ref Rectangle rectangleBeforeSizeMove, int maxSnapDistance, int cutoff)
{
// Evaluate left/right borders, then top/bottom borders.
// Initialize snap threshold.
int snapThresholdX = maxSnapDistance + 1;
switch (e.ResizeMode)
{
case ResizeMode.Left:
case ResizeMode.TopLeft:
case ResizeMode.BottomLeft:
LineSegment leftBorder = LeftEdge(ref e.MoveResizeRect, cutoff);
if (null != leftBorder)
{
foreach (LineSegment verticalSegment in VerticalSegments)
{
if (leftBorder.SnapSensitive(ref snapThresholdX, verticalSegment))
{
// Snap left border, preserve original location of right border of the rectangle.
e.MoveResizeRect.Left = verticalSegment.Position;
e.MoveResizeRect.Right = rectangleBeforeSizeMove.Right;
}
}
}
break;
case ResizeMode.Right:
case ResizeMode.TopRight:
case ResizeMode.BottomRight:
LineSegment rightBorder = RightEdge(ref e.MoveResizeRect, cutoff);
if (null != rightBorder)
{
foreach (LineSegment verticalSegment in VerticalSegments)
{
if (rightBorder.SnapSensitive(ref snapThresholdX, verticalSegment))
{
// Snap right border, preserve original location of left border of the rectangle.
e.MoveResizeRect.Left = rectangleBeforeSizeMove.Left;
e.MoveResizeRect.Right = verticalSegment.Position;
}
}
}
break;
}
// Initialize snap threshold.
int snapThresholdY = maxSnapDistance + 1;
switch (e.ResizeMode)
{
case ResizeMode.Top:
case ResizeMode.TopLeft:
case ResizeMode.TopRight:
LineSegment topBorder = TopEdge(ref e.MoveResizeRect, cutoff);
if (null != topBorder)
{
foreach (LineSegment horizontalSegment in HorizontalSegments)
{
if (topBorder.SnapSensitive(ref snapThresholdY, horizontalSegment))
{
// Snap top border, preserve original location of bottom border of the rectangle.
e.MoveResizeRect.Top = horizontalSegment.Position;
e.MoveResizeRect.Bottom = rectangleBeforeSizeMove.Bottom;
}
}
}
break;
case ResizeMode.Bottom:
case ResizeMode.BottomLeft:
case ResizeMode.BottomRight:
LineSegment bottomBorder = BottomEdge(ref e.MoveResizeRect, cutoff);
if (null != bottomBorder)
{
foreach (LineSegment horizontalSegment in HorizontalSegments)
{
if (bottomBorder.SnapSensitive(ref snapThresholdY, horizontalSegment))
{
// Snap bottom border, preserve original location of top border of the rectangle.
e.MoveResizeRect.Top = rectangleBeforeSizeMove.Top;
e.MoveResizeRect.Bottom = horizontalSegment.Position;
}
}
}
break;
}
}
/// <summary> /// Raises the <see cref="Resizing"/> event. /// </summary> /// <param name="e"> /// The <see cref="ResizeEventArgs"/> containing the event data. /// </param> protected virtual void OnResizing(ResizeEventArgs e) => Resizing?.Invoke(this, e);
