private static void LockToGrid(CanvasPixelPosition canvasOffset, [NotNull] TileCanvas target, ref double x, ref double y)
{
if (canvasOffset == null)
{
return;
}
var scale = 1.0 / target.CurrentZoom();
var grid = TileCanvas.GridSize * scale;
var bias = (3 * grid) / 5.0;
x = Math.Round((x + bias) / grid) * grid;
x -= (canvasOffset.X * scale) % grid;
y = Math.Round((y + bias) / grid) * grid;
y -= (canvasOffset.Y * scale) % grid;
}
/// <summary>
/// Continue a pen stroke
/// </summary>
public void Stroke(PointerEventArgs penEvent, CanvasPixelPosition canvasOffset, [NotNull] TileCanvas target)
{
try
{
if (penEvent?.CurrentPoint?.Properties == null)
{
return;
}
var x = penEvent.CurrentPoint.Position.X;
var y = penEvent.CurrentPoint.Position.Y;
var isEraser = penEvent.CurrentPoint.Properties.IsEraser || penEvent.CurrentPoint.Properties.IsRightButtonPressed; // treat right-click as erase
if (penEvent.KeyModifiers.HasFlag(VirtualKeyModifiers.Control))
{
// hacky straight line tool:
if (_stroke.Count > 1)
{
_stroke.RemoveAt(_stroke.Count - 1); // replace last point instead of adding a new one
}
}
if (penEvent.KeyModifiers.HasFlag(VirtualKeyModifiers.Menu))// this is actually *ALT*
{
LockToGrid(canvasOffset, target, ref x, ref y);
}
_stroke.Add(new DPoint
{
X = x,
Y = y,
StylusId = GuessPointerId(penEvent.CurrentPoint),
Pressure = penEvent.CurrentPoint.Properties.Pressure,
IsErase = isEraser
});
_renderTarget.Invalidate();
}
catch (Exception ex)
{
Logging.WriteLogMessage(ex.ToString());
}
}
