Refined positioning of vertex text labels

src/graph/draw/graph_cairo_draw.cc

@@ -436,7 +436,7 @@ public:
         if (text != "")
         {
             double text_pos = _attrs.template get<double>(VERTEX_TEXT_POSITION);
-            if (text_pos < 0)
+            if (text_pos == -1)
             {
                 cr.select_font_face(_attrs.template get<string>(VERTEX_FONT_FAMILY),
                                     static_cast<Cairo::FontSlant>(_attrs.template get<int32_t>(VERTEX_FONT_SLANT)),

src/graph_tool/draw/cairo_draw.py

@@ -550,7 +550,9 @@ def graph_draw(g, pos=None, vprops=None, eprops=None, vorder=None, eorder=None,
         |               | correspond to an angle in radians, which will     |                        |                                  |
         |               | determine where the text will be placed outside   |                        |                                  |
         |               | the vertex. If the value is negative, the text    |                        |                                  |
-        |               | will be placed inside the vertex.                 |                        |                                  |
+        |               | will be placed inside the vertex. If the value is |                        |                                  |
+        |               | ``-1``, the vertex size will be automatically     |                        |                                  |
+        |               | increased to accommodate the text.                |                        |                                  |
         +---------------+---------------------------------------------------+------------------------+----------------------------------+
         | font_family   | Font family used to draw the text.                | ``str``                | ``"serif"``                      |
         +---------------+---------------------------------------------------+------------------------+----------------------------------+