PDF 圖層（OCG）

Layers are Optional Content Groups (OCGs): named groups of page content that a viewer can show or hide, common in CAD exports, maps, and print files with separate language or markup layers. Most PDFs from office software have none, and the tool then shows an empty list with the option to add one.

No. Unchecking a layer changes the default visibility state saved in the PDF, so it opens hidden but can be switched back on in any viewer with a layers panel. Deleting a layer with the X button removes the layer group itself from the document's layer list.

Layers shown with a lock icon were marked locked by the PDF's creator, so their visibility can't be changed and the add-child and delete buttons are hidden for them. That lock is part of the file and the tool respects it.

You can add top-level layers and nested child layers by name, and they're saved into the PDF's layer configuration. This tool doesn't draw content onto a layer; it manages the layer list, so a new layer stays empty until another application assigns content to it.

Layer names and visibility states are written into the PDF's standard optional content dictionary, so any viewer with layer support reads them. Viewers without a layers panel still honor the default visibility, so a layer you hid stays hidden there.

Download Modified PDF saves the edited document under the same filename as the original, so rename it afterward if you want to keep both versions.

You're prompted for the password on upload, and the layer editor works on the decrypted copy. The saved file isn't encrypted.

No. The PDF is opened by PyMuPDF running as WebAssembly in your browser, layer changes are applied in memory, and the download is written on your device, which matters for CAD drawings and site plans that are often confidential.