first go at varying the line width based on highway classification

pkgs/maps/main.fnl

@@ -91,20 +91,38 @@ label.readout {
 
 (local cq (cqueues.new))
 
-(fn cairo-roads-path [g lines bounds]
+(fn road-width-for [line offset]
-  (each [_ line (pairs lines)]
+  (+ (or offset 0)
-    (case line.points
+     (case (?. line :tags :highway)
-      [[sx sy] & more]
+       :motorway 18
-      (do
+       :trunk 17
+       :primary 16
+       :secondary 14
+       :cycleway 4
+       :footway 4
+       other (do (print "highway " other) 12))))
+
+(fn cairo-road-path [g [[sx sy] & points] bounds width]
   (g:save)
+  (g:set_line_width width)
   (g:move_to (* tile-size (- sx bounds.min.x))
              (* tile-size (- sy bounds.min.y)))
-        (each [_ [x y] (ipairs more)]
+  (each [_ [x y] (ipairs points)]
     (let [x1 (* tile-size (- x bounds.min.x))
           y1 (* tile-size (- y bounds.min.y))]
       (g:line_to x1 y1)))
   (g:stroke)
-        (g:restore)))))
+  (g:restore))
+
+
+(fn cairo-roads [g lines bounds]
+  (let [road-width 14]
+    (g:set_source_rgb 0 0 0)
+    (each [_ line (pairs lines)]
+      (cairo-road-path g line.points bounds (road-width-for line)))
+    (g:set_source_rgb 1 1 1)
+    (each [_ line (pairs lines)]
+      (cairo-road-path g line.points bounds (road-width-for line -2)))))
 
 (fn label-coords [{ : points } bounds]
   (var biggest 0)
@@ -132,8 +150,6 @@ label.readout {
          (* tile-size (- ny bounds.min.y))
          (+ math.pi angle)))))
 
-
-
 (fn cairo-the-map [window]
   (let [{ : lat : lon : zoom } app-state
         { : num-tiles-x : num-tiles-y &as bounds } (map-bounds lat lon zoom)
@@ -156,12 +172,7 @@ label.readout {
       (g:rectangle 0 0 (* tile-size num-tiles-x) (* tile-size num-tiles-y))
       (g:fill)
 
-      (g:set_source_rgb 0 0 0)
+      (cairo-roads  g lines bounds)
-      (g:set_line_width road-width)
-      (cairo-roads-path g lines bounds)
-      (g:set_source_rgb 1 1 1)
-      (g:set_line_width (- road-width 2))
-      (cairo-roads-path g lines bounds)
 
       (g:set_source_rgb 0.2 0.2 0.2)
       (g:set_font_size (+ road-width 1))

pkgs/maps/tiles.fnl

@@ -71,6 +71,7 @@
          e.id
          {
           :name (?. e :tags :name)
+          :tags e.tags
           :points
           (icollect [_ nd (ipairs e.nodes)]
             (let [node (. nodes nd)