private void PositionHandles(Rect elemRect, SizingHandles ignore)
{
double halfSize = (SizingHandleSize / 2);
if (ignore != SizingHandles.TopLeft)
{
Canvas.SetLeft(m_handles[(int)SizingHandles.TopLeft], elemRect.Left - halfSize);
Canvas.SetTop(m_handles[(int)SizingHandles.TopLeft], elemRect.Top - halfSize);
}
if (ignore != SizingHandles.TopRight)
{
Canvas.SetLeft(m_handles[(int)SizingHandles.TopRight], elemRect.Right - halfSize);
Canvas.SetTop(m_handles[(int)SizingHandles.TopRight], elemRect.Top - halfSize);
}
if (ignore != SizingHandles.BottomLeft)
{
Canvas.SetLeft(m_handles[(int)SizingHandles.BottomLeft], elemRect.Left - halfSize);
Canvas.SetTop(m_handles[(int)SizingHandles.BottomLeft], elemRect.Bottom - halfSize);
}
if (ignore != SizingHandles.BottomRight)
{
Canvas.SetLeft(m_handles[(int)SizingHandles.BottomRight], elemRect.Right - halfSize);
Canvas.SetTop(m_handles[(int)SizingHandles.BottomRight], elemRect.Bottom - halfSize);
}
}
protected override void OnPreviewMouseLeftButtonDown(MouseButtonEventArgs e)
{
base.OnPreviewMouseLeftButtonDown(e);
bool hadSelection = false;
this.m_isDragging = false;
this.m_isDraggingHandle = false;
this.m_origLocation = e.GetPosition(this);
// Mark that we had a previously selected element
if (this.m_selectedElement != null)
hadSelection = true;
// Get the selected element (also the one being dragged)
this.m_dragElement = this.FindCanvasChild(e.Source as DependencyObject);
// If the selection is null, do nothing
if (this.m_dragElement == null)
{
this.m_selectedElement = null;
// If we had a previous selection, hide the handles
if (hadSelection)
SetHandleVisibility(false);
if (OnSelectedElementChanged != null && hadSelection)
OnSelectedElementChanged(this, new EventArgs());
return;
}
// Check if we are dragging a handle
for (int i = 0; i < m_handles.Length; i++)
{
if (this.m_dragElement == m_handles[i])
{
this.m_isDraggingHandle = true;
this.m_isDragHandleSelected = (SizingHandles)i;
break;
}
}
// Get the position of the element (NaN's mean the object isn't bound to the side)
double left = Canvas.GetLeft(this.m_dragElement);
double right = Canvas.GetRight(this.m_dragElement);
double top = Canvas.GetTop(this.m_dragElement);
double bottom = Canvas.GetBottom(this.m_dragElement);
// FE of element being dragged
FrameworkElement fse = (FrameworkElement)this.m_dragElement;
// Normalize coordinates of the element (if they're whacko)
if (Double.IsNaN(left))
{
double nl = right - fse.Width;
Canvas.SetLeft(this.m_dragElement, nl);
Canvas.SetRight(this.m_dragElement, Double.NaN);
}
if (Double.IsNaN(top))
{
double nt = bottom - fse.Height;
Canvas.SetTop(this.m_dragElement, nt);
Canvas.SetBottom(this.m_dragElement, Double.NaN);
}
m_origX = Canvas.GetLeft(this.m_dragElement);
m_origY = Canvas.GetTop(this.m_dragElement);
// If we aren't dragging a handle, cache the rectangle of the selected element
if (!m_isDraggingHandle)
{
if (this.m_dragElement != this.m_selectedElement)
{
this.m_selectedElement = this.m_dragElement;
if (OnSelectedElementChanged != null)
OnSelectedElementChanged(this, new EventArgs());
}
double x = Canvas.GetLeft(this.m_selectedElement);
double y = Canvas.GetTop(this.m_selectedElement);
this.m_origSelectedRect = new Rect(x, y, fse.Width, fse.Height);
// Position the sizing handles around the object
PositionHandles(this.m_origSelectedRect, SizingHandles.BottomCentre);
// If we didn't have a previous selections, show the handles
if (!hadSelection)
SetHandleVisibility(true);
}
this.m_newSelectedRect = this.m_origSelectedRect;
// Mark that we will drag
this.m_isDragging = true;
// Mark that we handles the mouse down
e.Handled = true;
}