Painting tool: use more sensible defaults for painting data layer

Namely, pre-define object label map filter. Also fix some initial
display problems, due to the wrong opacity.

Author: tomka

django/applications/catmaid/static/js/layers/painting-layer.js

@@ -106,6 +106,7 @@
       this.updateContextConfiguration();
     } else if (name === 'value') {
       this.value = value;
+      this.dataLayer.setLayerSetting('backgroundLabel', value);
     } else if (name === 'dtype') {
       this.dtype = dtype;
     } else if (name === 'brushSize') {
@@ -278,7 +279,7 @@
         }
 
         // Write block back to server. This is done asynchronously in regular
-        // intervald (if changes happen).
+        // intervals (if changes happen).
         return this.dataLayer.writeBlock(project.id, this.stackViewer.s, zoom, ...blockCoord, block);
       })
       .catch(CATMAID.handleError);

django/applications/catmaid/static/js/tools/painting-tool.js

@@ -279,7 +279,7 @@
             stackViewer.primaryStack,
             customMirrorData.id,
             isVisible,
-            isVisible ? 0 : 1,
+            isVisible ? 1 : 0,
             showOverview,
             CATMAID.StackLayer.INTERPOLATION_MODES.INHERIT,
             changeMirrorIfNoData);
@@ -289,6 +289,15 @@
         CATMAID.setLocalStorageItem(self.customMirrorStorageName,
             JSON.stringify(customMirrorData));
 
+        // Add an "Object label color map" filter after WebGL is available, to
+        // render the painted labels
+        const backgroundLabel = 0;
+        const filter = new (dataLayer.getAvailableFilters()["Object Label Color Map"])();
+        filter.setParam("backgroundLabel", CATMAID.PixiLayer.Filters.int2arr(Number(backgroundLabel)));
+        filter.setParam("foregroundAlpha", 0.8);
+        filter.setParam("seed", 0.09);
+        dataLayer.addFilter(filter);
+
         // Update layer control UI to reflect settings changes.
         if (self.stackViewer && self.stackViewer.layerControl) {
           self.layerControl.refresh();