Inline RendererBase._get_text_path_transform.

This private helper is only used in a single place (and not by
subclasses).  Inlining it makes it clearer that this is not something
third-party backends need to worry about (and avoids having to duplicate
the description of the parameters).

Also clarify the actual behavior of the `ismath` parameter in
`draw_text`.

Author: anntzer

lib/matplotlib/backend_bases.py

@@ -510,75 +510,44 @@ def draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None):
         angle : float
             The rotation angle in degrees anti-clockwise.
         ismath : bool or "TeX"
-            If True, use mathtext parser. If "TeX", use tex for rendering.
+            If True, use mathtext parser.
         mtext : `~matplotlib.text.Text`
             The original text object to be rendered.
+
+        Notes
+        -----
+        **Notes for backend implementers:**
+
+        `.RendererBase.draw_text` also supports passing "TeX" to the *ismath*
+        parameter to use TeX rendering, but this is not required for actual
+        rendering backends, and indeed many builtin backends do not support
+        this.  Rather, TeX rendering is provided by `~.RendererBase.draw_tex`.
         """
         self._draw_text_as_path(gc, x, y, s, prop, angle, ismath)
 
-    def _get_text_path_transform(self, x, y, s, prop, angle, ismath):
+    def _draw_text_as_path(self, gc, x, y, s, prop, angle, ismath):
         """
-        Return the text path and transform.
+        Draw the text by converting them to paths using `.TextToPath`.
 
-        Parameters
-        ----------
-        x : float
-            The x location of the text in display coords.
-        y : float
-            The y location of the text baseline in display coords.
-        s : str
-            The text to be converted.
-        prop : `~matplotlib.font_manager.FontProperties`
-            The font property.
-        angle : float
-            Angle in degrees to render the text at.
-        ismath : bool or "TeX"
-            If True, use mathtext parser. If "TeX", use tex for rendering.
+        This private helper supports the same parameters as
+        `~.RendererBase.draw_text`; setting *ismath* to "TeX" triggers TeX
+        rendering.
         """
-
         text2path = self._text2path
         fontsize = self.points_to_pixels(prop.get_size_in_points())
         verts, codes = text2path.get_text_path(prop, s, ismath=ismath)
-
         path = Path(verts, codes)
-        angle = np.deg2rad(angle)
         if self.flipy():
             width, height = self.get_canvas_width_height()
             transform = (Affine2D()
                          .scale(fontsize / text2path.FONT_SCALE)
-                         .rotate(angle)
+                         .rotate_deg(angle)
                          .translate(x, height - y))
         else:
             transform = (Affine2D()
                          .scale(fontsize / text2path.FONT_SCALE)
-                         .rotate(angle)
+                         .rotate_deg(angle)
                          .translate(x, y))
-
-        return path, transform
-
-    def _draw_text_as_path(self, gc, x, y, s, prop, angle, ismath):
-        """
-        Draw the text by converting them to paths using `.TextToPath`.
-
-        Parameters
-        ----------
-        gc : `.GraphicsContextBase`
-            The graphics context.
-        x : float
-            The x location of the text in display coords.
-        y : float
-            The y location of the text baseline in display coords.
-        s : str
-            The text to be converted.
-        prop : `~matplotlib.font_manager.FontProperties`
-            The font property.
-        angle : float
-            Angle in degrees to render the text at.
-        ismath : bool or "TeX"
-            If True, use mathtext parser. If "TeX", use tex for rendering.
-        """
-        path, transform = self._get_text_path_transform(
-            x, y, s, prop, angle, ismath)
         color = gc.get_rgb()
         gc.set_linewidth(0.0)
         self.draw_path(gc, path, transform, rgbFace=color)