add dds support for text-offset

src/data/bucket/symbol_bucket.js

@@ -323,7 +323,6 @@ class SymbolBucket {
         const lineHeight = layout['text-line-height'] * oneEm;
         const maxWidth = layout['symbol-placement'] !== 'line' ? layout['text-max-width'] * oneEm : 0;
         const spacing = layout['text-letter-spacing'] * oneEm;
-        const textOffset = [layout['text-offset'][0] * oneEm, layout['text-offset'][1] * oneEm];
         const fontstack = this.fontstack = layout['text-font'].join(',');
         const textAlongLine = layout['text-rotation-alignment'] === 'map' && layout['symbol-placement'] === 'line';
 
@@ -332,6 +331,7 @@ class SymbolBucket {
             let shapedTextOrientations;
             if (feature.text) {
                 const allowsVerticalWritingMode = scriptDetection.allowsVerticalWritingMode(feature.text);
+                const textOffset = this.layers[0].getLayoutValue('text-offset', {zoom: this.zoom}, feature.properties).map((t)=> t * oneEm);
 
                 shapedTextOrientations = {
                     [WritingMode.horizontal]: shapeText(feature.text, stacks[fontstack], maxWidth, lineHeight, horizontalAlign, verticalAlign, justify, spacing, textOffset, oneEm, WritingMode.horizontal),

src/style-spec/reference/v8.json

@@ -1408,6 +1408,7 @@
       "units": "ems",
       "function": "interpolated",
       "zoom-function": true,
+      "property-function": true,
       "length": 2,
       "default": [
         0,
@@ -1423,7 +1424,9 @@
           "ios": "2.0.0",
           "macos": "0.1.0"
         },
-        "data-driven styling": {}
+        "data-driven styling": {
+          "js": "0.35.0"
+        }
       }
     },
     "text-allow-overlap": {

test/integration/render-tests/text-offset/property-function/style.json

@@ -0,0 +1,70 @@
+{
+  "version": 8,
+  "metadata": {
+    "test": {
+      "width": 100,
+      "height": 100
+    }
+  },
+  "sources": {
+    "geojson": {
+      "type": "geojson",
+      "data": {
+        "type": "FeatureCollection",
+        "features": [
+          {
+            "type": "Feature",
+            "properties": {
+              "offset": [0,1]
+            },
+            "geometry": {
+              "type": "Point",
+              "coordinates": [
+                -10,
+                0
+              ]
+            }
+          },
+          {
+            "type": "Feature",
+            "properties": {
+              "offset": [1,-1]
+            },
+            "geometry": {
+              "type": "Point",
+              "coordinates": [
+                10,
+                0
+              ]
+            }
+          }
+        ]
+      }
+    }
+  },
+  "glyphs": "local://glyphs/{fontstack}/{range}.pbf",
+  "sprite": "local://sprites/sprite",
+  "layers": [
+    {
+      "id": "symbol",
+      "type": "symbol",
+      "source": "geojson",
+      "layout": {
+        "text-field": "hello",
+        "icon-image": "oneway",
+        "text-offset": {
+          "type": "identity",
+          "property": "offset"
+        },
+        "text-font": [
+          "Open Sans Semibold",
+          "Arial Unicode MS Bold"
+        ],
+        "text-size": 10
+      },
+      "paint": {
+        "text-color": "black"
+      }
+    }
+  ]
+}