I realize this is intentionally a bare bones app, and I like the simplicity. However, there does appear to be some basic functionality missing.
1. Undo/Redo
Seems like a basic need to me, would make editing easier. It’s annoying & frustrating to correct errors by having to erase multiple tiles to just fix a misplaced door.
2. Object tiles
Is a dungeon map really a dungeon map without some object tiles? Even if it’s just square tiles with letters, such as “S” for statue or “T” for trap. Maybe even add the ability to import custom tiles as long as they meet tile size criteria in pixels.
3. Layering
I think layering would be a great addition to the app. This way you can erase only what you need to. Put floor tiles on one layer, put walls, doors & windows on another, put objects on another. Adding a few extra layers, say 5 total, would make editing the maps much easier.
4. Grid Size
Needs the ability to edit the grid size and maybe the grid line type. This would make creating maps much easier since smaller maps could be made without a massive number of empty squares.
5. A Legend & Custom text
Adding the ability to add a legend to the map would be a massive plus. It’d allow people to create and edit what objects/tiles have on the. Adding custom text would help with adding any notes you might need to add. Such as how many feet each tile represents.
6. Event Markers
Adding the ability to add custom event markers would help a lot as well. It would give users the ability to edit and control all content in the app before printing it out.
I’m not sure what the end goal for this app is, but these basic functions would be great additions.