Show direction legends in all four cardinals

lib/xmet/hodograph.py

@@ -113,8 +113,50 @@ class Hodograph():
 
                 cr.move_to(x + sx + extents.width * 0.25,
                            y + sy - extents.height * 1.5)
+
                 cr.show_text(text)
-                cr.stroke()
+
+        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)
+
+        cr.set_font_size(14)
+
+        for text in legends:
+            extents = cr.text_extents(text)
+            fx, fy  = legends[text]
+
+            cr.move_to(fx(extents), fy(extents))
+            cr.show_text(text)
 
         cr.restore()
 
@@ -263,7 +305,6 @@ class Hodograph():
 
             cr.move_to(offset + x - extents.width / 4, y + 3.5*width)
             cr.show_text(text)
-            cr.stroke()
 
             offset += interval
 
@@ -279,6 +320,7 @@ class Hodograph():
         self.draw_sounding(cr, x, y, sounding)
 
         self.draw_speed_legends(cr, x, y)
+        self.draw_direction_legends(cr, x, y)
         self.draw_height_legends(cr, x, y)
 
         cr.reset_clip()