public void DrawFilledRectangle(Pen pen, int x_start, int y_start, int width, int height)
{
if (height == -1)
{
height = width;
}
for (int y = y_start; y < y_start + height; y++)
{
canvas.DrawLine(pen, x_start, y, x_start + width + 1, y);
}
}
