refactor(voxel-annotations): rework chunk reloading pipeline -> wait for the entire downsample cascade before reloading chunks, this fixes the disappearing preview at low res.

Author: briossant

src/sliceview/volume/frontend.ts

@@ -342,7 +342,6 @@ export class InMemoryVolumeChunkSource extends VolumeChunkSource {
       }
     };
     // adding a small delay to avoid flickering since the base source will take some time to download the new data
-    // TODO: it would be better to reload the preview once the base source is good, with big brushes this delay is not sufficient
     setTimeout(update, 100);
   }
 

src/voxel_annotation/TODOs.md

@@ -7,13 +7,11 @@
 
 ### later
 
-- should we allow drawing even when there are no writable volume, and in that case inform the user about it and only draw edits in the preview layer? I am not sure about the real use cases tho.
 - add preview for the undo/redo
-- optimize flood fill tool (it is too slow on area containing uncached chunks, due to the getEnsuredValueAt() calls)
 - the flood fill sometimes leaves artifacts in sharp areas (maybe increase fillBorderRegion() radius)
-- write a testsuite for the downsampler and ensure its proper working on exotic lod levels
 
 ### questionable
 
+- write a testsuite for the downsampler and ensure its proper working on exotic lod levels
 - design a dataset creation feature
 - adapt the brush size to the zoom level linearly

src/voxel_annotation/edit_backend.ts

@@ -195,7 +195,6 @@ export class VoxelEditController extends SharedObject {
         if (firstErrorMessage === undefined) firstErrorMessage = msg;
       }
     }
-    this.callChunkReload(editsByVoxKey.keys().toArray());
 
     if (newAction.changes.size > 0) {
       this.undoStack.push(newAction);
@@ -273,7 +272,13 @@ export class VoxelEditController extends SharedObject {
       while (this.downsampleQueue.length > 0) {
         const key = this.downsampleQueue.shift() as string;
         this.downsampleQueueSet.delete(key);
-        await this.performDownsampleCascadeForKey(key);
+        const allModifiedKeys = new Array<string>();
+        let currentKey: string | null = key;
+        while (currentKey !== null) {
+          allModifiedKeys.push(currentKey);
+          currentKey = await this.downsampleStep(currentKey);
+        }
+        this.callChunkReload(allModifiedKeys);
       }
     } finally {
       this.isProcessingDownsampleQueue = false;
@@ -287,15 +292,6 @@ export class VoxelEditController extends SharedObject {
     }
   }
 
-  private async performDownsampleCascadeForKey(
-    sourceKey: string,
-  ): Promise<void> {
-    let currentKey: string | null = sourceKey;
-    while (currentKey !== null) {
-      currentKey = await this.downsampleStep(currentKey);
-    }
-  }
-
   /**
    * Performs a single downsampling step from a child chunk to its parent.
    * @returns The key of the parent chunk that was updated, or null if the cascade should stop.