fix GroupTileLayer's tilesize (#1429)

* fix GroupTileLayer's tilesize, fix #1425

* fixing specs

* fixing specs

Author: fuzhenn

src/layer/tile/GroupTileLayer.js

@@ -1,11 +1,15 @@
 import { pushIn } from '../../core/util';
 import Layer from '../Layer';
 import TileLayer from './TileLayer';
+import Size from '../../geo/Size';
 
 const options = {
     'maxCacheSize': 1024
 };
 
+
+const DEFAULT_TILESIZE = new Size(256, 256);
+
 /**
  * @classdesc
  * A layer used to display a group of tile layers. <br>
@@ -88,6 +92,14 @@ class GroupTileLayer extends TileLayer {
         return profile;
     }
 
+    getTileSize(id) {
+        const layer = this.getLayer(id);
+        if (!layer) {
+            return DEFAULT_TILESIZE;
+        }
+        return layer.getTileSize();
+    }
+
     /**
      * Get tiles at zoom (or current zoom)
      * @param {Number} z
@@ -139,6 +151,10 @@ class GroupTileLayer extends TileLayer {
         super.onRemove();
     }
 
+    getLayer(id) {
+        return this.getChildLayer(id);
+    }
+
     getChildLayer(id) {
         const layer = this.layerMap[id];
         if (layer) {

src/renderer/layer/tilelayer/TileLayerCanvasRenderer.js

@@ -345,7 +345,7 @@ class TileLayerCanvasRenderer extends CanvasRenderer {
     }
 
     loadTile(tile) {
-        const tileSize = this.layer.getTileSize();
+        const tileSize = this.layer.getTileSize(tile.layer);
         const tileImage = new Image();
 
         tileImage.width = tileSize['width'];
@@ -446,7 +446,7 @@ class TileLayerCanvasRenderer extends CanvasRenderer {
             tileZoom = tileInfo.z,
             tileId = tileInfo.id;
         const map = this.getMap(),
-            tileSize = this.layer.getTileSize(),
+            tileSize = this.layer.getTileSize(tileInfo.layer),
             zoom = map.getZoom(),
             ctx = this.context,
             cp = map._pointToContainerPoint(point, tileZoom, 0, TEMP_POINT),

src/renderer/layer/tilelayer/TileLayerGLRenderer.js

@@ -36,7 +36,7 @@ class TileLayerGLRenderer extends ImageGLRenderable(TileLayerCanvasRenderer) {
         }
 
         const scale = tileInfo._glScale = tileInfo._glScale || map.getGLScale(tileInfo.z);
-        const size = this.layer.getTileSize();
+        const size = this.layer.getTileSize(tileInfo.layer);
         const w = size.width;
         const h = size.height;
         if (tileInfo.cache !== false) {