add get_layer and get_layer_ids API

docs/api.md

@@ -252,6 +252,24 @@ class ImJoyPlugin():
 api.export(ImJoyPlugin())
 ```
 
+### get_layer_ids()
+
+Get all the layer ids.
+
+**Returns**
+An array of layer ids.
+
+### get_layer(key)
+
+Get a layer by its id or name.
+
+**Arguments**
+ - `key`: String, the id or name of the layer
+
+**Returns**
+The layer object corresponding to the id or name.
+If the layer is not found, it will return `null`.
+
 ### add_widget(options)
 
 Add a widget panel with buttons, file tree or graph.

src/components/ImageViewer.vue

@@ -485,6 +485,18 @@ export default {
         config._add_layer_promise = { resolve, reject };
       });
     },
+    getLayer(key) {
+      for (let config of this.$store.state.layer_configs) {
+        // name or id
+        if (config.name === key || config.id === key) {
+          const layer = this.$store.state.layers[config.id];
+          return layer.getLayerAPI();
+        }
+      }
+    },
+    getLayerIds() {
+      return this.$store.state.layer_configs.map(config => config.id);
+    },
     updateExtent(config) {
       //TODO: calculate the extent for all layers
       const projection = new Projection({
@@ -528,6 +540,8 @@ export default {
       if (window.self !== window.top) {
         setupImJoyAPI({
           addLayer: this.addLayer,
+          getLayer: this.getLayer,
+          getLayerIds: this.getLayerIds,
           selectLayer: this.selectLayer,
           removeLayer: this.removeLayer,
           clearLayers: this.clearLayers,

src/components/layers/VectorLayer.vue

@@ -867,7 +867,6 @@ export default {
           });
           return routeFeatures;
         },
-
         get_selected_features(config) {
           config = config || {};
           if (config.decimals === undefined) config.decimals = 2;

src/imjoyAPI.js

@@ -53,6 +53,8 @@ function toArray(data) {
 
 export async function setupImJoyAPI({
   addLayer,
+  getLayer,
+  getLayerIds,
   selectLayer,
   removeLayer,
   clearLayers,
@@ -103,6 +105,8 @@ export async function setupImJoyAPI({
       }
     },
     add_layer: addLayer,
+    get_layer: getLayer,
+    get_layer_ids: getLayerIds,
     select_layer: selectLayer,
     remove_layer: removeLayer,
     clear_layers: clearLayers,