implement symbol-sort

mapbox · Apr 7, 2015 · 5bf094f · 5bf094f
1 parent 2ea1b1c
commit 5bf094f
Showing 1 changed file with 21 additions and 0 deletions.
diff --git a/js/data/symbol_bucket.js b/js/data/symbol_bucket.js
@@ -26,6 +26,7 @@ function SymbolBucket(buffers, layoutProperties, collision, overscaling, collisi
  this.collision = collision;
  this.overscaling = overscaling;
  this.collisionDebug = collisionDebug;
+ this.sortedAngle = undefined;
 
  this.symbolInstances = [];
 
@@ -191,6 +192,22 @@ SymbolBucket.prototype.placeFeatures = function(buffers, collisionDebug) {
  var textAlongLine = layout['text-rotation-alignment'] === 'map' && layout['symbol-placement'] === 'line';
  var iconAlongLine = layout['icon-rotation-alignment'] === 'map' && layout['symbol-placement'] === 'line';
 
+ if (layout['symbol-sort'] !== undefined && this.sortedAngle !== this.collision.angle) {
+
+ var sortAngle = layout['symbol-sort'] / 180 * Math.PI;
+ var angle = this.collision.angle - sortAngle;
+ var sin = Math.sin(angle),
+ cos = Math.cos(angle);
+
+ this.symbolInstances.sort(function(a, b) {
+ var aRotated = sin * a.x + cos * a.y;
+ var bRotated = sin * b.x + cos * b.y;
+ return bRotated - aRotated;
+ });
+
+ this.sortedAngle = this.collision.angle;
+ }
+
  for (var p = 0; p < this.symbolInstances.length; p++) {
  var symbolInstance = this.symbolInstances[p];
  var hasText = symbolInstance.hasText;
@@ -397,6 +414,9 @@ function SymbolInstance(anchor, line, shapedText, shapedIcon, layout, inside,
  textBoxScale, textPadding, textAlongLine,
  iconBoxScale, iconPadding, iconAlongLine) {
 
+ this.x = anchor.x;
+ this.y = anchor.y;
+
  this.hasText = !!shapedText;
  this.hasIcon = !!shapedIcon;
 
@@ -409,4 +429,5 @@ function SymbolInstance(anchor, line, shapedText, shapedIcon, layout, inside,
  this.iconQuads = inside ? getIconQuads(anchor, shapedIcon, iconBoxScale, line, layout, iconAlongLine) : [];
  this.iconCollisionFeature = new CollisionFeature(line, anchor, shapedIcon, iconBoxScale, iconPadding, iconAlongLine);
  }
+
 }