add alwaysVisible option to disable text collision, close #315

mapbox · Mar 15, 2014 · 02da93b · 02da93b
1 parent ad95064
commit 02da93b
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Showing 3 changed files with 8 additions and 5 deletions.
diff --git a/debug/style.js b/debug/style.js
@@ -124,7 +124,8 @@ var style_json = {
             "text_field": "name",
             "path": "horizontal",
             "font": "Open Sans, Jomolhari, Siyam Rupali, Alef, Arial Unicode MS",
-            "fontSize": 18
+            "fontSize": 18,
+            "alwaysVisible": true
         },
         "road_label": {
             "source": "mapbox streets",

diff --git a/js/text/collision.js b/js/text/collision.js
@@ -33,7 +33,7 @@ function Collision() {
 
 }
 
-Collision.prototype.place = function(boxes, anchor, minPlacementScale, maxPlacementScale, padding, horizontal) {
+Collision.prototype.place = function(boxes, anchor, minPlacementScale, maxPlacementScale, padding, horizontal, alwaysVisible) {
 
     var minScale = Infinity;
     for (var m = 0; m < boxes.length; m++) {
@@ -73,13 +73,14 @@ Collision.prototype.place = function(boxes, anchor, minPlacementScale, maxPlacem
     }
 
     // Calculate the minimum scale the entire label can be shown without collisions
-    var scale = this.getPlacementScale(boxes, minPlacementScale, maxPlacementScale, padding);
+    var scale = alwaysVisible ? minPlacementScale :
+            this.getPlacementScale(boxes, minPlacementScale, maxPlacementScale, padding);
 
     // Return if the label can never be placed without collision
     if (scale === null) return null;
 
     // Calculate the range it is safe to rotate all glyphs
-    var rotationRange = this.getPlacementRange(boxes, scale, horizontal);
+    var rotationRange = alwaysVisible ? [2 * Math.PI, 0] : this.getPlacementRange(boxes, scale, horizontal);
     this.insert(boxes, anchor, scale, rotationRange, horizontal, padding);
 
     var zoom = Math.log(scale) / Math.LN2;

diff --git a/js/text/placement.js b/js/text/placement.js
@@ -62,7 +62,8 @@ Placement.prototype.addFeature = function(line, info, faces, shaping) {
     for (var j = 0, len = anchors.length; j < len; j++) {
         var anchor = anchors[j];
         var glyphs = getGlyphs(anchor, advance, shaping, faces, fontScale, horizontal, line, maxAngleDelta, rotate);
-        var place = this.collision.place(glyphs, anchor, anchor.scale, this.maxPlacementScale, padding, horizontal);
+        var place = this.collision.place(
+            glyphs, anchor, anchor.scale, this.maxPlacementScale, padding, horizontal, info.alwaysVisible);
 
         if (place) {
             this.geometry.addGlyphs(glyphs, place.zoom, place.rotationRange, this.zoom - this.zOffset);