From f64bfeb7fd5171755df1f5f052936f7ef1603185 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Thu, 29 May 2025 21:09:24 +0100
Subject: [PATCH] invalidate map only when app-state changes

---
 pkgs/maps/main.fnl | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/pkgs/maps/main.fnl b/pkgs/maps/main.fnl
index dadd191..e349eab 100644
--- a/pkgs/maps/main.fnl
+++ b/pkgs/maps/main.fnl
@@ -76,11 +76,9 @@ label.readout {
 ;; to fill the width of the screen plus a bit
 
 (fn cairo-the-map [self g]
-  (: (self:get_window) :invalidate_rect nil)
   (let [{ : lat : lon : zoom } app-state
         num-tiles-x (+ 0 (math.ceil (/ map-width tile-size)))
         num-tiles-y (+ 0 (math.ceil (/ map-height tile-size)))
-        ; _ (print app-state.lat app-state.lon)
         (tile-x tile-y) (tiles.latlon->tile app-state.lat app-state.lon app-state.zoom)
         min-tile-x (math.floor (- tile-x (/ num-tiles-x 2)))
         max-tile-x (math.ceil (+ tile-x (/ num-tiles-x 2)))
@@ -115,12 +113,17 @@ label.readout {
     (g:stroke)
     true))
 
+(fn register-widget [name widget]
+  (tset state-widgets name widget)
+  widget)
 
 (fn osm-widget []
-  (Gtk.DrawingArea {
-              :width map-width :height map-height
-              :on_draw  cairo-the-map
-              }))
+  (register-widget
+   :osm
+   (Gtk.DrawingArea {
+                     :width map-width :height map-height
+                     :on_draw  cairo-the-map
+                     })))
 
 (fn readout [name text]
   (let [w
@@ -153,7 +156,7 @@ label.readout {
     (case name
       :speed (widget:set_label
               (string.format "%.1f km/h" (* app-state.speed 3.6)))
-      :osm (widget:set_center app-state.lat app-state.lon)
+      :osm (: (widget:get_window) :invalidate_rect nil)
       :time (widget:set_label
              (hhmmss (+ utc-offset app-state.time-of-day)))
       )))