public static void StraightLine(WriteableBitmap b, int x, int y, int width, Color color)
{
byte[] oldBytes = null;
bmp = b;
if (!isSelecting)
{
startPoint = new P(x, y);
}
currentPoint = new P(x, y);
if (isSelecting)
{
oldBytes = History.Undo().bmp;
bmp.PixelBuffer.AsStream().Write(oldBytes, 0, oldBytes.Length);
}
isSelecting = true;
bmp.DrawLineCustom(startPoint.x, startPoint.y, currentPoint.x, currentPoint.y, color, width);
oldBytes = bmp.PixelBuffer.ToArray();
bmp.PixelBuffer.ToArray().CopyTo(oldBytes, 0);
History.EndAction(new Action(oldBytes));
}