private void autoScrollTimer_Tick(object sender, EventArgs e)
{
m_autoScrollTimer.Stop();
if (!VisibleClientRectangle.Contains(m_currentPoint))
{
if (m_isMultiSelecting)
{
Rectangle selectionRect = MakeSelectionRect(m_currentPoint, m_firstPoint);
ControlPaint.DrawReversibleFrame(selectionRect, BackColor, FrameStyle.Dashed);
}
const int autoScrollSpeed = 10;
Rectangle visibleRect = VisibleClientRectangle;
Point scroll = m_scroll;
if (m_currentPoint.X < 0)
{
scroll.X += autoScrollSpeed;
}
else if (m_currentPoint.X > visibleRect.Width)
{
scroll.X -= autoScrollSpeed;
}
if (m_currentPoint.Y < 0)
{
scroll.Y += autoScrollSpeed;
}
else if (m_currentPoint.Y > visibleRect.Height)
{
scroll.Y -= autoScrollSpeed;
}
Point diff = m_scroll;
ScrollPosition = new Point(scroll.X, scroll.Y);
diff.X = m_scroll.X - diff.X;
diff.Y = m_scroll.Y - diff.Y;
// adjust mouse positions
m_firstPoint.X += diff.X;
m_firstPoint.Y += diff.Y;
m_last = m_currentPoint;
OnAutoScroll();
base.Update(); // without this, the selection rect doesn't draw correctly
if (m_isMultiSelecting)
{
Rectangle rect = MakeSelectionRect(m_currentPoint, m_firstPoint);
ControlPaint.DrawReversibleFrame(rect, BackColor, FrameStyle.Dashed);
}
m_autoScrollTimer.Start();
}
}
/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Control.MouseMove"></see> event</summary>
/// <param name="e">A <see cref="T:System.Windows.Forms.MouseEventArgs"></see> that contains the event data</param>
protected override void OnMouseMove(MouseEventArgs e)
{
m_last = m_currentPoint;
m_currentPoint = new Point(e.X, e.Y);
int xDelta = Math.Abs(m_currentPoint.X - m_firstPoint.X);
int yDelta = Math.Abs(m_currentPoint.Y - m_firstPoint.Y);
if (m_isDragging &&
!m_dragOverThreshold &&
(xDelta > m_dragThreshold || yDelta > m_dragThreshold))
{
m_dragOverThreshold = true;
if (m_constrain)
{
m_constrainX = (xDelta < yDelta);
}
}
if (m_constrain)
{
if (m_constrainX)
{
m_currentPoint.X = m_firstPoint.X;
}
else
{
m_currentPoint.Y = m_firstPoint.Y;
}
}
if (m_dragOverThreshold)
{
Point delta = DragDelta;
// auto scroll if mouse is outside control
if (m_autoScroll && !VisibleClientRectangle.Contains(m_currentPoint) && !m_autoScrollTimer.Enabled)
{
m_autoScrollTimer.Start();
}
if (m_isMultiSelecting)
{
Rectangle rect;
rect = MakeSelectionRect(m_last, m_firstPoint);
ControlPaint.DrawReversibleFrame(rect, BackColor, FrameStyle.Dashed);
rect = MakeSelectionRect(m_currentPoint, m_firstPoint);
ControlPaint.DrawReversibleFrame(rect, BackColor, FrameStyle.Dashed);
}
else if (m_isScrolling)
{
ScrollPosition = new Point(
m_autoScrollPositionStart.X + delta.X,
m_autoScrollPositionStart.Y + delta.Y);
}
else if (m_isZooming)
{
float xScale = 1 + 2 * delta.X / (float)Width;
float yScale = 1 + 2 * delta.Y / (float)Height;
if (m_constrain || UniformZoom)
{
xScale = yScale = Math.Max(xScale, yScale);
}
SetZoom(m_xZoomStart * xScale, m_yZoomStart * yScale);
ScrollPosition = new Point((int)(m_firstPoint.X - m_zoomCenterStart.X * m_xZoom),
(int)(m_firstPoint.Y - m_zoomCenterStart.Y * m_yZoom));
}
}
base.OnMouseMove(e);
}
