[gnome-maps] transitPlan: Add function to get compact route labels

[Marcus Lundblad <mlundblad src gnome org>]

commit d81b7a958d19329e6b82a8545880d873c5148d2b
Author: Marcus Lundblad <ml update uu se>
Date:   Tue Jun 27 22:15:20 2017 +0200

    transitPlan: Add function to get compact route labels
    
    This was moved from the TransitRouteLabel class to be used
    when rendering itinerary overviews.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=784231

 src/transitPlan.js |   33 +++++++++++++++++++++++++++++++++
 1 files changed, 33 insertions(+), 0 deletions(-)
---
diff --git a/src/transitPlan.js b/src/transitPlan.js
index 13c7cc1..e08fa2d 100644
--- a/src/transitPlan.js
+++ b/src/transitPlan.js
@@ -419,12 +419,45 @@ const Leg = new Lang.Class({
         this.parent(params);
 
         this.bbox = this._createBBox();
+
+        this._compactRoute = null;
     },
 
     get route() {
         return this._route;
     },
 
+    // try to get a shortened route name, suitable for overview rendering
+    get compactRoute() {
+        if (this._compactRoute)
+            return this._compactRoute;
+
+        if (this._route.startsWith(this._agencyName)) {
+            /* if the agency name is a prefix of the route name, display the
+             * agency name in the overview, this way we get a nice "transition"
+             * into the expanded route showing the full route name
+             */
+            this._compactRoute = this._agencyName;
+        } else if (this._tripShortName &&
+                   (this._agencyName.length < this._tripShortName.length)) {
+            /* if the agency name is shorter than the trip short name,
+             * which can sometimes be a more "internal" number, like a
+             * "train number", which is less known by the general public,
+             * prefer the agency name */
+            this._compactRoute = this._agencyName;
+        } else if (this._tripShortName && this._tripShortName.length <= 6) {
+            /* if the above conditions are unmet, use the trip short name
+             * as a fallback if it was shorter than the original route name */
+            this._compactRoute = this._tripShortName;
+        } else {
+            /* if none of the above is true, use the original route name,
+             * and rely on label ellipsization */
+            this._compactRoute = this._route;
+        }
+
+        return this._compactRoute;
+    },
+
     get routeType() {
         return this._routeType;
     },