/// <summary>
/// Snap single element to close elements on canvas
/// </summary>
/// <param name="movedItem">Item to snap</param>
/// <param name="canvas">Main canvas holding all items</param>
private void SnapElement(ContentPresenter movedItem, CustomCanvas canvas)
{
double itemLeft = Canvas.GetLeft(movedItem);
double itemTop = Canvas.GetTop(movedItem);
TemplateViewModel context = (TemplateViewModel)canvas.DataContext;
// get list of close items according to snapDeltaPixels value
List <ContentPresenter> presenters = ControlHelper.GetUnselectedChildPresenters(canvas).ToList();
List <ContentPresenter> closeByLeft = presenters.Where(x => Math.Abs(Canvas.GetLeft(x) - itemLeft) <= snapDeltaPixels).ToList();
List <ContentPresenter> closeByTop = presenters.Where(x => Math.Abs(Canvas.GetTop(x) - itemTop) <= snapDeltaPixels).ToList();
List <Line> resultingSnapLines = new List <Line>();
if (closeByLeft.Count > 0)
{
// closest by left position and then by top
ContentPresenter closest = closeByLeft.OrderBy(x => Math.Abs(Canvas.GetLeft(x) - itemLeft))
.ThenBy(x => Math.Abs(Canvas.GetTop(x) - itemTop)).First();
// move snapped item to desired position
double targetLeft = Canvas.GetLeft(closest);
double targetTop = Canvas.GetTop(closest);
Canvas.SetLeft(movedItem, targetLeft);
// add lowest item height to the line length
double itemHeight = targetTop > itemTop ? closest.Height : movedItem.Height;
// draw snap line and add to the list
Line line = new Line();
line.X1 = line.X2 = targetLeft;
line.Y1 = Math.Max(Math.Min(itemTop, targetTop) - snapLineTail, 0);
line.Y2 = Math.Max(itemTop, targetTop) + itemHeight + snapLineTail;
resultingSnapLines.Add(line);
}
if (closeByTop.Count > 0)
{
// closes by top position and then by left
ContentPresenter closest = closeByTop.OrderBy(x => Math.Abs(Canvas.GetTop(x) - itemTop))
.ThenBy(x => Math.Abs(Canvas.GetLeft(x) - itemLeft)).First();
// move snapped item to desired position
double targetLeft = Canvas.GetLeft(closest);
double targetTop = Canvas.GetTop(closest);
Canvas.SetTop(movedItem, targetTop);
double itemWidth = targetLeft > itemLeft ? closest.Width : movedItem.Width;
// draw snap line and add to the list
Line line = new Line();
line.Y1 = line.Y2 = targetTop;
line.X1 = Math.Max(Math.Min(itemLeft, targetLeft) - snapLineTail, 0);
line.X2 = Math.Max(itemLeft, targetLeft) + itemWidth + snapLineTail;
resultingSnapLines.Add(line);
}
if (context.GotSnapLines)
{
context.CleanSnapLines();
}
// draw snap lines
foreach (Line snapLine in resultingSnapLines)
{
context.AddLine(snapLine);
}
}
/// <summary>
/// Snap group of elements
/// </summary>
/// <param name="movedGroup">Group of elements to snap</param>
/// <param name="canvas">Main canvas holding all items</param>
private void SnapGroup(List <ContentPresenter> movedGroup, CustomCanvas canvas)
{
// get bounding box Rect of snap group
Rect boundingBox = GetBoundingBox(movedGroup);
TemplateViewModel context = (TemplateViewModel)canvas.DataContext;
List <ContentPresenter> canvasItems = ControlHelper.GetUnselectedChildPresenters(canvas).ToList();
// get list of close items according to snapDeltaPixels value
List <Line> resultingSnapLines = new List <Line>();
List <ContentPresenter> closeByLeft = canvasItems.Where(x => Math.Abs(Canvas.GetLeft(x) - boundingBox.Left) <= snapDeltaPixels).ToList();
List <ContentPresenter> closeByTop = canvasItems.Where(x => Math.Abs(Canvas.GetTop(x) - boundingBox.Top) <= snapDeltaPixels).ToList();
if (closeByLeft.Count > 0)
{
// closes by left position and then by top
ContentPresenter closest = closeByLeft.OrderBy(x => Math.Abs(Canvas.GetLeft(x) - boundingBox.Left))
.ThenBy(x => Math.Abs(Canvas.GetTop(x) - boundingBox.Top)).First();
double targetLeft = Canvas.GetLeft(closest);
double targetTop = Canvas.GetTop(closest);
// snap each item of the group according to calculated distance to the target
double moveDelta = boundingBox.Left - targetLeft;
movedGroup.ForEach(x => Canvas.SetLeft(x, Canvas.GetLeft(x) - moveDelta));
// add lowest item height to the line length
double itemHeight = targetTop > boundingBox.Top ? closest.Height : boundingBox.Height;
// draw snap line and add to the list
Line line = new Line();
line.X1 = line.X2 = targetLeft;
line.Y1 = Math.Max(Math.Min(boundingBox.Top, targetTop) - snapLineTail, 0);
line.Y2 = Math.Max(boundingBox.Top, targetTop) + itemHeight + snapLineTail;
resultingSnapLines.Add(line);
}
if (closeByTop.Count > 0)
{
// closes by top position and then by left
ContentPresenter closest = closeByTop.OrderBy(x => Math.Abs(Canvas.GetTop(x) - boundingBox.Top))
.ThenBy(x => Math.Abs(Canvas.GetLeft(x) - boundingBox.Left)).First();
double targetLeft = Canvas.GetLeft(closest);
double targetTop = Canvas.GetTop(closest);
// snap each item of the group according to calculated distance to the target
double moveDelta = boundingBox.Top - targetTop;
movedGroup.ForEach(x => Canvas.SetTop(x, Canvas.GetTop(x) - moveDelta));
double itemWidth = targetLeft > boundingBox.Left ? closest.Width : boundingBox.Width;
// draw snap line and add to the list
Line line = new Line();
line.Y1 = line.Y2 = targetTop;
line.X1 = Math.Max(Math.Min(boundingBox.Left, targetLeft) - snapLineTail, 0);
line.X2 = Math.Max(boundingBox.Left, targetLeft) + itemWidth + snapLineTail;
resultingSnapLines.Add(line);
}
if (context.GotSnapLines)
{
context.CleanSnapLines();
}
// draw snap lines
foreach (Line snapLine in resultingSnapLines)
{
context.AddLine(snapLine);
}
}