Merge branch 'vdumont-layout_unique'

index.js

@@ -19,9 +19,55 @@ function heightAscThanNameComparator(a, b) {
  * @param {Function} callback
  */
 function generateLayout(imgs, pixelRatio, format, callback) {
-    assert(typeof pixelRatio === 'number' && Array.isArray(imgs));
-    var q = new queue();
+    return generateLayoutInternal(imgs, pixelRatio, format, false, callback);
+}
+
+/**
+ * Same as generateLayout but can be used to dedupe identical SVGs
+ * and still preserve the reference.
+ * For example if A.svg and B.svg are identical, a single icon
+ * will be in the sprite image and both A and B will reference the same image
+ */
+function generateLayoutUnique(imgs, pixelRatio, format, callback) {
+    return generateLayoutInternal(imgs, pixelRatio, format, true, callback);
+}
 
+function generateLayoutInternal(imgs, pixelRatio, format, unique, callback) {
+    assert(typeof pixelRatio === 'number' && Array.isArray(imgs));
+
+    if (unique) {
+        /* If 2 items are pointing to identical buffers (svg icons)
+         * create a single image in the sprite but have all ids point to it
+         * Remove duplicates from imgs, but if format == true then when creating the 
+         * resulting layout, make sure all item that had the same signature 
+         * of an item are also updated with the same layout information.
+        */
+
+        /* The svg signature of each item */
+        var svgPerItemId = {}
+
+        /* The items for each SVG signature */
+        var itemIdsPerSvg = {};
+
+        imgs.forEach(function(item) {
+            var svg = item.svg.toString('base64');
+
+            svgPerItemId[item.id] = svg;
+
+            if (svg in itemIdsPerSvg) {
+                itemIdsPerSvg[svg].push(item.id);
+            } else {
+                itemIdsPerSvg[svg] = [item.id];
+            }
+        });
+
+        /* Only keep 1 item per svg signature for packing */
+        imgs = imgs.filter(function(item) {
+            var svg = svgPerItemId[item.id];
+            return item.id === itemIdsPerSvg[svg][0]
+        });
+    }
+
     function createImagesWithSize(img, callback) {
         mapnik.Image.fromSVGBytes(img.svg, { scale: pixelRatio }, function(err, image) {
             if (err) return callback(err);
@@ -36,6 +82,8 @@ function generateLayout(imgs, pixelRatio, format, callback) {
         });
     }
 
+    var q = new queue();
+
     imgs.forEach(function(img) {
         q.defer(createImagesWithSize, img);
     });
@@ -51,13 +99,20 @@ function generateLayout(imgs, pixelRatio, format, callback) {
         if (format) {
             var obj = {};
             imagesWithSizes.forEach(function(item) {
-                obj[item.id] = {
-                    width: item.width,
-                    height: item.height,
-                    x: item.x,
-                    y: item.y,
-                    pixelRatio: pixelRatio
-                };
+                var itemIdsToUpdate = [item.id];
+                if (unique) {
+                    var svg = svgPerItemId[item.id];
+                    itemIdsToUpdate = itemIdsPerSvg[svg];
+                }
+                itemIdsToUpdate.forEach(function(itemIdToUpdate) {
+                    obj[itemIdToUpdate] = {
+                        width: item.width,
+                        height: item.height,
+                        x: item.x,
+                        y: item.y,
+                        pixelRatio: pixelRatio
+                    };
+                });
             });
             return callback(null, obj);
 
@@ -72,6 +127,7 @@ function generateLayout(imgs, pixelRatio, format, callback) {
     });
 }
 module.exports.generateLayout = generateLayout;
+module.exports.generateLayoutUnique = generateLayoutUnique;
 
 /**
  * Generate a PNG image with positioned icons on a sprite.

package.json

@@ -20,7 +20,8 @@
     "mapnik": "~3.5.0",
     "queue-async": "^1.0.7",
     "shelf-pack": "1.0.0",
-    "xtend": "^4.0.1"
+    "xtend": "^4.0.1",
+    "json-stable-stringify": "^1.0.1"
   },
   "devDependencies": {
     "dox": "^0.8.0",