What the Big File Map shows in DeDup 1.5.3 on Android

The Big File Map in DeDup 1.5.3 on Android draws your internal storage as a treemap: one coloured block per folder, sized by how many bytes the folder holds. It's for seeing where space went. You can look and drill down. You can't delete from it.

Opening it and building the map

The only way in, in this version's code, is the storage card at the top of the Storage Insights screen. Tapping that card opens the Big File Map. You first see "Storage Treemap", the line "Visualize which folders are consuming your space." and a "Build Map" button. Tapping it shows "Building storage map..." while DeDup works.

How the map is built

On Android 11 and newer, DeDup queries the system media store for every file with a size above zero, using each file's folder path and size. It adds the size to every folder along that path. This needs no All Files permission, a code comment says.

Some storage isn't in the media store, such as other apps' data and system data. DeDup takes used space from the phone's storage statistics, subtracts what the media store accounted for, and shows the difference as one block named "System & Restricted Data" when it's above zero. The root is "Internal Storage", and its total is the used space from those statistics.

On Android 10 and older, DeDup walks the folders with the file API instead, using the storage-read permission. It skips names starting with a dot, adds up folders below a set depth into their parent, and adds the same remainder block.

How it's drawn

The layout code sorts blocks from largest to smallest and gives each a share of the space equal to its share of the total bytes. It cuts along the longer side of the available area. Each top-level block also holds its sub-folders, drawn one level deep inside it. Folders with zero bytes are left out.

A block gets a name and size label only if it's big enough for the text to fit. Under the map, a legend lists up to the first 8 folders with their colours and sizes. The map uses a palette of eight colours, so colours repeat on busy maps.

Moving around

• The header shows "Total: ... Tap to drill down", and a "Rescan" button.
• Tap a block to open that folder. If several blocks overlap under your finger, the smallest one is chosen, so you can tap a nested sub-folder directly.
• Tapping a block with no sub-folders does nothing, so the "System & Restricted Data" block can't be opened.
• The folder you're in is named under the screen title. The back arrow goes up one level, and from the top level it leaves the screen.

What you can't do here

There's no select, delete or open-file action on this screen. The only controls are "Build Map", "Rescan", "Retry" after an error, tapping blocks and going back. The name says "file" but the map shows folders. Files sitting directly in a folder add to that folder's size and don't get their own block. To act on what you find, use the scanners or Agent Mode, which do their own deletion through the system prompt, permanently.

Scope of this post

Checked against: DeDup 1.5.3 source code (Android).

Not tested on a device: how long the map takes to build, how closely it matches the storage screen in Android's settings, how readable the labels are on small blocks, and the older-Android file-walking path. All of it was read from the code and strings, not run.