From 0eecc408396b300328c6b6acd38a835eaf08d5a8 Mon Sep 17 00:00:00 2001
From: XANTRONIX Industrial <xan@xantronix.com>
Date: Mon, 3 Mar 2025 22:15:10 -0500
Subject: [PATCH] Draw basic direction legends at the top and bottom of graph

---
 lib/xmet/hodograph.py | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/lib/xmet/hodograph.py b/lib/xmet/hodograph.py
index 2a1d8e0..cb6a42f 100644
--- a/lib/xmet/hodograph.py
+++ b/lib/xmet/hodograph.py
@@ -118,6 +118,37 @@ class Hodograph():
 
         cr.restore()
 
+    def draw_direction_legends(self, cr: cairo.Context, x, y):
+        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
+        extents = cr.text_extents(text)
+
+        cr.move_to(x + cx - extents.width / 2,
+                   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()
+
     COLORS = {
           500: (1.0, 0.4, 1.0),
          3000: (1.0, 0.4, 0.4),
@@ -279,6 +310,7 @@ 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()