Edits no longer wait for auto-save

With auto-save on, Labelme writes the annotation file after every edit. Until now, each edit and each Undo waited for that write to finish. On a small file you never noticed. On a large one, such as an annotation file that stores the Image inside it, moving a vertex paused the app for a moment.

In Labelme v7.8.0, saving happens in the background. Your edit appears on the canvas at once, and Labelme writes the file afterward. The status bar reads Saving… while the write runs and Saved once the file on disk matches the canvas.

In the implementation's own measurement, with a 24.9 MB Image stored in the annotation file, an edit took 77 to 116 ms before the change and less than a millisecond after it.

A failed save stays on screen#

A save can fail when the disk is full or the folder is read-only. Before v7.8.0, the first failure interrupted you with a dialog and later ones showed nothing. Now Save failed stays in the status bar next to a Retry button, and you can keep editing.

Hover over the status to see the destination file and the reason. Labelme tries again on your next edit or when you choose Retry, as described in the status bar change. Until a save succeeds, your last saved annotation stays intact.

Labelme waits before leaving an Image#

Opening another Image, closing the window, Save As, and Delete File all wait for the write in progress, so moving quickly does not drop an edit. If the latest save failed, Labelme asks whether to save, discard, or cancel before it leaves the Image.

Background saving is not crash recovery. An edit made in the instant before a crash or power loss may not be on disk. The design record lists this limit.