adjust font sizes in response to zoom changes

screens/main

@@ -65,6 +65,9 @@ function car.touch_move(id, x,y, ...)
       local c = centroid(curr[f], curr[s])
       v.x = v.x + c.x/oldzoom - c.x/v.zoom
       v.y = v.y + c.y/oldzoom - c.y/v.zoom
+      for _,w in ipairs(widgets) do
+        if w.refresh_font then w.refresh_font() end
+      end
     end end end
 
 function car.mouse_release(x,y, b) 

screens/text-box

@@ -120,14 +120,17 @@ function add_editor()
   table.insert(widgets, adjh)
 
   -- font buttons
-  local update_font = function(newf)
-    if font_height == newf then return end
-    font_height = newf
+  r.refresh_font = function()
     e.font_height = scale(font_height)
     e.font = g.newFont(e.font_height)
     e.line_height = floor(e.font_height)*1.3
     Text.redraw_all(e)
   end
+  local update_font = function(newf)
+    if font_height == newf then return end
+    font_height = newf
+    r.refresh_font()
+  end
   table.insert(widgets, {
     draw = function()
       color(0.7,0.7,0.7)