Studio is where you review a generated diagram and make it yours. Edit the .dgm source, move and resize items on the canvas, add resources or notes, organise layers, adjust connectors, and export the result. Source and visual changes stay together in the same file.
Chromium-based desktop browsers are the first-class Studio target. WebKit and Firefox are best-effort compatibility targets, and native Safari is not a release target.
Open and edit a file
Run dumbdiagrams studio and choose Open to select any .dgm file. Keep the terminal running while you work. Studio listens on 127.0.0.1, port 4788, or a free port if that one is taken.
Moving an item never rearranges the rest of the diagram. Other items and connector paths stay where they are, and the moved item’s connections redraw along the straightest clear path. Auto-fix repairs overlaps and crossings in one step. The button shows a spinner while it works, and Undo restores the previous layout.
A partially typed source edit may be temporarily invalid. Studio keeps the last valid compilation visible while you fix it. If the picture seems unchanged, check the validation feedback before assuming the edit was saved.
For a keyboard-friendly overview of the diagram, open Canvas items. It lists boundaries, resources, connectors, and annotations and lets you focus or safely delete the selected item.
Fine-tune the details
Select a boundary, resource, or connector to edit it on the right: line and fill, label position, icon size, step numbers, connector meaning, and route. The defaults work without changes, so these are optional refinements. Clicking a warning in the validation panel selects the item it refers to.
Save and work with other editors
In browsers with the File System Access API, Save writes back to the opened file and Save As picks a new one. Before writing, Studio checks whether another editor changed or deleted the file and asks you to reload or overwrite. Other browsers download the updated .dgm instead, without that check. Saved source is canonical, so diffs stay small. Nothing is uploaded.