Rename/change signature of PyGlyph_new.

Unlike all other ExtensionType_new functions, PyGlyph_new is not a
tp_new (https://docs.python.org/3/c-api/typeobj.html#c.PyTypeObject.tp_new)
but simply a plain C function used to construct a struct from the fields
of a FT2Font.  Rename it to avoid confusion, and make it take a single
FT2Font as argument, too (with some additional fixes for
const-correctness).

Author: anntzer

src/ft2font.h

@@ -93,27 +93,27 @@ class FT2Font
     long get_name_index(char *name);
     PyObject* get_path();
 
-    FT_Face &get_face()
+    FT_Face const &get_face() const
     {
         return face;
     }
     FT2Image &get_image()
     {
         return image;
     }
-    FT_Glyph &get_last_glyph()
+    FT_Glyph const &get_last_glyph() const
     {
         return glyphs.back();
     }
-    size_t get_last_glyph_index()
+    size_t get_last_glyph_index() const
     {
         return glyphs.size() - 1;
     }
-    size_t get_num_glyphs()
+    size_t get_num_glyphs() const
     {
         return glyphs.size();
     }
-    long get_hinting_factor()
+    long get_hinting_factor() const
     {
         return hinting_factor;
     }

src/ft2font_wrapper.cpp

@@ -179,8 +179,13 @@ typedef struct
 static PyTypeObject PyGlyphType;
 
 static PyObject *
-PyGlyph_new(const FT_Face &face, const FT_Glyph &glyph, size_t ind, long hinting_factor)
+PyGlyph_from_FT2Font(const FT2Font *font)
 {
+    const FT_Face &face = font->get_face();
+    const FT_Glyph &glyph = font->get_last_glyph();
+    size_t ind = font->get_last_glyph_index();
+    long hinting_factor = font->get_hinting_factor();
+
     PyGlyph *self;
     self = (PyGlyph *)PyGlyphType.tp_alloc(&PyGlyphType, 0);
 
@@ -625,10 +630,7 @@ static PyObject *PyFT2Font_load_char(PyFT2Font *self, PyObject *args, PyObject *
 
     CALL_CPP("load_char", (self->x->load_char(charcode, flags)));
 
-    return PyGlyph_new(self->x->get_face(),
-                       self->x->get_last_glyph(),
-                       self->x->get_last_glyph_index(),
-                       self->x->get_hinting_factor());
+    return PyGlyph_from_FT2Font(self->x);
 }
 
 const char *PyFT2Font_load_glyph__doc__ =
@@ -664,10 +666,7 @@ static PyObject *PyFT2Font_load_glyph(PyFT2Font *self, PyObject *args, PyObject
 
     CALL_CPP("load_glyph", (self->x->load_glyph(glyph_index, flags)));
 
-    return PyGlyph_new(self->x->get_face(),
-                       self->x->get_last_glyph(),
-                       self->x->get_last_glyph_index(),
-                       self->x->get_hinting_factor());
+    return PyGlyph_from_FT2Font(self->x);
 }
 
 const char *PyFT2Font_get_width_height__doc__ =