private ITileMapSelection ChooseSelection()
{
ITileMapSelection result = null;
if (DesignControl.AltKeyHeld)
{
var firstIndex = TileMap1D.GetTileIndex(
FirstGridTile,
TileMap.GridWidth);
var activeIndex = TileMap1D.GetTileIndex(
ActiveGridTile,
TileMap.GridWidth);
var originIndex = Min(firstIndex, activeIndex);
var endIndex = Max(firstIndex, activeIndex);
var count = endIndex - originIndex + 1;
result = new LinearTileMapSelection(
firstIndex < activeIndex ? FirstGridTile : ActiveGridTile,
count,
TileMap.GridWidth);
}
else
{
var origin = new Point(
Min(FirstGridTile.X, ActiveGridTile.X),
Min(FirstGridTile.Y, ActiveGridTile.Y));
var end = new Point(
Max(FirstGridTile.X, ActiveGridTile.X),
Max(FirstGridTile.Y, ActiveGridTile.Y));
var size = new Size(
end.X + 1 - origin.X,
end.Y + 1 - origin.Y);
result = new BoxTileMapSelection(
origin,
size,
TileMap.GridWidth);
}
if (DesignControl.ControlKeyHeld && CurrentSelection != null)
{
result = new EnumerableTileMapSelection(
CurrentSelection.Union(result),
TileMap.GridWidth);
}
return(result);
}