Change line_to path method to behave like move_to for empty paths - gsl-shell.git - gsl-shell

diff --git a/agg-plot/lua-draw.cpp b/agg-plot/lua-draw.cpp
index b9a3a13e..4148c3c8 100644
--- a/agg-plot/lua-draw.cpp
+++ b/agg-plot/lua-draw.cpp

@@ -147,7 +147,10 @@ path_cmd (draw::path *p, int _cmd, struct cmd_call_stack *s)

ps.move_to (s->f[0], s->f[1]);

break;

case CMD_LINE_TO:

- ps.line_to (s->f[0], s->f[1]);

+ if (ps.total_vertices() == 0)

+ ps.move_to (s->f[0], s->f[1]);

+ else

+ ps.line_to (s->f[0], s->f[1]);

break;

case CMD_CLOSE:

ps.close_polygon ();

diff --git a/doc/user-manual/graphics.rst b/doc/user-manual/graphics.rst
index b331f35c..443acfb2 100644
--- a/doc/user-manual/graphics.rst
+++ b/doc/user-manual/graphics.rst

@@ -658,6 +658,11 @@ Graphical Objects

.. method:: line_to(x, y)

Add a line into the path from the previous point to the specified (x, y) coordinates.

+ As a special case, if the path is empty, this method is equivalent to :meth:`~Path.move_to`.

+

+ .. hint::

+ If you want to define a polygonal line you don't need to use the :meth:`~Path.move_to` method for the first point.

+ Instead you can use the method :meth:`~Path.line_to` to add each point.

.. method:: close()