Show direction legends in all four cardinals

lib/xmet/hodograph.py

@@ -119,33 +119,44 @@ class Hodograph():
         cr.restore()
 
     def draw_direction_legends(self, cr: cairo.Context, x, y):
+        cx, cy = self.sample_to_screen(0, 0)
+
+        legends = {
+            '0°': (
+                lambda e: x + cx - e.width / 2,
+                lambda e: y + self.height - 2 * e.height
+            ),
+
+            '90°': (
+                lambda e: x + cx - e.width  * 2,
+                lambda e: y + cy + e.height / 2
+            ),
+
+            '180°': (
+                lambda e: x + cx - e.width / 2,
+                lambda e: y + 2 * e.height
+            ),
+
+            '270°': (
+                lambda e: x + self.width - e.width * 2,
+                lambda e: y + cy + e.height / 2
+            )
+        }
+
         cr.save()
 
         cr.select_font_face('Sans',
                             cairo.FONT_SLANT_NORMAL,
                             cairo.FONT_WEIGHT_BOLD)
 
-        cx, cy = self.sample_to_screen(0, 0)
-
         cr.set_font_size(14)
 
-        text    = "%d°" % 180
+        for text in legends:
             extents = cr.text_extents(text)
+            fx, fy  = legends[text]
 
-        cr.move_to(x + cx - extents.width / 2,
+            cr.move_to(fx(extents), fy(extents))
-                   y + 4 * extents.height)
-
             cr.show_text(text)
-        cr.stroke()
-
-        text    = "%d°" % 0
-        extents = cr.text_extents(text)
-
-        cr.move_to(x + cx - extents.width / 2,
-                   y + self.height - 4 * extents.height)
-
-        cr.show_text(text)
-        cr.stroke()
 
         cr.restore()