// Arrange the orientation of a polygon, all polygons in a path,
// or in all paths. After calling arrange_orientations() or
// arrange_orientations_all_paths(), all the polygons will have
// the same orientation, i.e. path_flags_cw or path_flags_ccw
//--------------------------------------------------------------------
public int arrange_polygon_orientation(int start, ShapePath.FlagsAndCommand orientation)
{
if (orientation == ShapePath.FlagsAndCommand.FlagNone)
{
return(start);
}
// Skip all non-vertices at the beginning
while (start < vertices.total_vertices() &&
!ShapePath.is_vertex(vertices.command(start)))
{
++start;
}
// Skip all insignificant move_to
while (start + 1 < vertices.total_vertices() &&
ShapePath.is_move_to(vertices.command(start)) &&
ShapePath.is_move_to(vertices.command(start + 1)))
{
++start;
}
// Find the last vertex
int end = start + 1;
while (end < vertices.total_vertices() &&
!ShapePath.is_next_poly(vertices.command(end)))
{
++end;
}
if (end - start > 2)
{
if (perceive_polygon_orientation(start, end) != orientation)
{
// Invert polygon, set orientation flag, and skip all end_poly
invert_polygon(start, end);
ShapePath.FlagsAndCommand PathAndFlags;
while (end < vertices.total_vertices() &&
ShapePath.is_end_poly(PathAndFlags = vertices.command(end)))
{
vertices.modify_command(end++, PathAndFlags | orientation); // Path.set_orientation(cmd, orientation));
}
}
}
return(end);
}
public void modify_command(int index, ShapePath.FlagsAndCommand PathAndFlags)
{
vertices.modify_command(index, PathAndFlags);
}