private static void SetResizingMouseCursor(ResizeClickPosition clickPos)
{
Cursor newCursor = null;
switch (clickPos)
{
case ResizeClickPosition.Left:
case ResizeClickPosition.Right:
newCursor = Cursors.SizeWE;
break;
case ResizeClickPosition.Top:
case ResizeClickPosition.Bottom:
newCursor = Cursors.SizeNS;
break;
case ResizeClickPosition.LeftTop:
case ResizeClickPosition.RightBottom:
newCursor = Cursors.SizeNWSE;
break;
case ResizeClickPosition.RightTop:
case ResizeClickPosition.LeftBottom:
newCursor = Cursors.SizeNESW;
break;
}
if (Mouse.OverrideCursor != newCursor)
{
Mouse.OverrideCursor = newCursor;
}
}
/// <summary>
/// Start dragging
/// </summary>
/// <param name="e"></param>
protected override void OnPreviewMouseLeftButtonDown(MouseButtonEventArgs e)
{
if (_isBeingDragged)
{
return;
}
base.OnPreviewMouseLeftButtonDown(e);
if (_selectedElement == null)
{
return;
}
_dragStartCursorPos = e.GetPosition(this);
double x = GetLeft(_selectedElement);
double y = GetTop(_selectedElement);
switch (Mode)
{
case DragMode.Move:
_dragStartElementPos = new Point(x, y);
SetMovingMouseCursor();
break;
case DragMode.Resize:
_dragStartElementRect = new Rect(x, y, _selectedElement.Width, _selectedElement.Height);
_resizeClickPos = DetectResizeClickPosition(_dragStartCursorPos, _dragStartElementRect);
SetResizingMouseCursor(_resizeClickPos);
break;
}
_selectedElement.CaptureMouse();
_isBeingDragged = true;
e.Handled = true;
}
private static Rect CalcNewSize(Point cursorStart, Point cursorNow, Rect elementRect, ResizeClickPosition clickPos)
{
const int MinLineLen = 16;
// Do not touch Width and Height if border was not clicked
switch (clickPos)
{
case ResizeClickPosition.Inside:
case ResizeClickPosition.Outside:
return(elementRect);
}
// Get delta of X and Y
double xDelta = cursorNow.X - cursorStart.X;
double yDelta = cursorNow.Y - cursorStart.Y;
// Prepare variables
double x = elementRect.X;
double y = elementRect.Y;
double width = elementRect.Width;
double height = elementRect.Height;
// X Direction
switch (clickPos)
{
case ResizeClickPosition.Left:
case ResizeClickPosition.LeftTop:
case ResizeClickPosition.LeftBottom:
if (Math.Abs(xDelta) < double.Epsilon)
{
break;
}
if (0 < xDelta)
{ // L [-> ] R, delta is positive
if (xDelta + MinLineLen < width)
{
x += xDelta;
width -= xDelta;
}
else
{ // Guard
x += width - MinLineLen;
width = MinLineLen;
}
}
else
{ // L <-[ ] R, delta is negative
x += xDelta;
width -= xDelta;
}
break;
case ResizeClickPosition.Right:
case ResizeClickPosition.RightTop:
case ResizeClickPosition.RightBottom:
if (Math.Abs(xDelta) < double.Epsilon)
{
break;
}
if (0 < xDelta)
{ // L [ ]-> R, delta is positive
width += xDelta;
}
else
{ // L [ <-] R, delta is negative
if (MinLineLen < width + xDelta) // Guard
{
width += xDelta;
}
else
{
width = MinLineLen;
}
}
break;
}
// Y Direction
switch (clickPos)
{
case ResizeClickPosition.Top:
case ResizeClickPosition.LeftTop:
case ResizeClickPosition.RightTop:
if (Math.Abs(yDelta) < double.Epsilon)
{
break;
}
if (0 < yDelta)
{ // T [-> ] B, delta is positive
if (yDelta + MinLineLen < height)
{
y += yDelta;
height -= yDelta;
}
else
{ // Guard
y += height - MinLineLen;
height = MinLineLen;
}
}
else
{ // T <-[ ] B, delta is negative
y += yDelta;
height -= yDelta;
}
break;
case ResizeClickPosition.Bottom:
case ResizeClickPosition.LeftBottom:
case ResizeClickPosition.RightBottom:
if (Math.Abs(yDelta) < double.Epsilon)
{
break;
}
if (0 < yDelta)
{ // T [ ]-> B, delta is positive
height += yDelta;
}
else
{ // T [ <-] B, delta is negative
if (MinLineLen < height + yDelta) // Guard
{
height += yDelta;
}
else
{
height = MinLineLen;
}
}
break;
}
// Check if X and Width is correct
switch (clickPos)
{
case ResizeClickPosition.Left:
case ResizeClickPosition.LeftTop:
case ResizeClickPosition.LeftBottom:
if (x < 0)
{
width += x;
x = 0;
}
break;
case ResizeClickPosition.Right:
case ResizeClickPosition.RightTop:
case ResizeClickPosition.RightBottom:
if (CanvasWidthHeightLimit + ElementWidthHeightLimit < x + width)
{
width = CanvasWidthHeightLimit + ElementWidthHeightLimit - x;
}
break;
}
// Check if Y and Height is correct
switch (clickPos)
{
case ResizeClickPosition.Top:
case ResizeClickPosition.LeftTop:
case ResizeClickPosition.RightTop:
if (y < 0)
{
height += y;
y = 0;
}
break;
case ResizeClickPosition.Bottom:
case ResizeClickPosition.LeftBottom:
case ResizeClickPosition.RightBottom:
if (CanvasWidthHeightLimit + ElementWidthHeightLimit < y + height)
{
height = CanvasWidthHeightLimit + ElementWidthHeightLimit - y;
}
break;
}
return(new Rect(x, y, width, height));
}
