DiskTreemap

A fast, single-file disk-usage treemap viewer for Windows — a lightweight alternative to SpaceSniffer. Pick a drive or folder, and it renders an interactive squarified treemap you can drill into, with a right-click menu for native file operations.

The whole app is one self-contained .exe built from a single C# file. No browser, no local server, no runtime to install beyond what ships with Windows.

English · 简体中文

Features

• Native WinForms UI — a single ~100 KB executable built from one source file, with no browser and no HTTP service involved.
• SpaceSniffer-style picker — on launch you choose a drive or a folder and an aggregation threshold, instead of scanning something immediately.
• Fast scanner — walks the tree with Parallel.ForEach (CPU x2 workers) and enumerates directories through the native FindFirstFileEx (FindExInfoBasic
  • large fetch), so name, attributes and size arrive in one call with no per-entry syscall and no 8.3 short-name lookup. Skips junctions / symlinks (files as well as directories) to avoid loops and double counting.
• Honest totals — directories that cannot be read are skipped and counted; the count is reported in the CLI output and the window title, so an under-reported size is never silently passed off as exact.
• Small-file aggregation — files below the threshold are collapsed into a single (N small files) node per folder, keeping the output legible.
• Nested container view — every folder is drawn as a labelled frame with a header bar, so the root drive and each level down are visually distinct.
• Drill-down navigation — double-click a folder cell to make it the new root; double-clicking a file jumps the view to the folder that holds it, and only opens the file when it already sits directly inside the current view. Back / up / path history are all available from the title bar.
• Native context actions — open, reveal in Explorer, properties, copy path or name, and move to the Recycle Bin (restorable in the usual case; an item too large for the bin, or on a drive without one, is deleted permanently and the system warns before doing so).
• Custom borderless window — macOS-style traffic-light buttons, an integrated icon toolbar, a rounded path pill and rounded window corners.
• Light / dark theme — follows the Windows app theme automatically (AppsUseLightTheme, refreshed on WM_SETTINGCHANGE). A one-click toggle sits in the title bar, and a manual choice is remembered in HKCU\Software\DiskTreemap so it survives restarts.
• Automatic English / Chinese UI — the interface language follows the Windows display language (Chinese for zh-*, English otherwise). Every label, tooltip, menu and CLI message is localised.
• System-DPI aware — the process declares DPI awareness so the UI is drawn at the native resolution instead of being bitmap-stretched on scaled displays. This is system DPI awareness, not per-monitor: on a mixed-DPI multi-monitor setup the window may not rescale after being moved to a differently scaled display.
• Headless CLI mode — scan to JSON without opening a window.

Project layout

File	Purpose
DiskTreemap.cs	The entire application: scanner, treemap layout, renderer, WinForms UI and CLI.
build.ps1	Compiles DiskTreemap.cs into DiskTreemap.exe.
verify.ps1	CLI acceptance suite (19 assertions).
app.manifest	Win32 manifest: asInvoker, supported OS list, DPI awareness.
app.ico	Multi-resolution application icon (16 / 32 / 48 / 64 / 256).
docs/screenshot.png	Application screenshot used in this README.
README.md	This file.
使用说明.md	End-user guide (Chinese).
CHANGELOG.md	Release history.
CONTRIBUTING.md	How to build, test and submit changes.
SECURITY.md	How to report a vulnerability.
LICENSE	MIT licence.
.gitignore	Ignores the build output (*.exe) and scratch files.
.gitattributes	Pins line endings to LF so checkouts are deterministic.
.github/workflows/build.yml	CI: builds the exe and runs the acceptance suite.
.github/ISSUE_TEMPLATE/	Issue templates.

DiskTreemap.exe is a build artifact and is not committed — run build.ps1 to produce it, or grab the one attached to the latest release.

Requirements

• Windows 7 SP1 or later (Windows 10 / 11 recommended). The UI is a WinForms application, so it needs the .NET Framework 4.x runtime — included with Windows 8 and later; on Windows 7, install .NET Framework 4.x first.
• Building from source needs only the C# compiler (csc.exe) that ships with the .NET Framework — no SDK, no Visual Studio, no NuGet restore.

Build

powershell -NoProfile -ExecutionPolicy Bypass -File build.ps1

Requires the .NET Framework 4.x C# compiler (csc.exe), which ships with Windows. The script locates it automatically and prints the output size.

Run the acceptance suite afterwards:

powershell -NoProfile -ExecutionPolicy Bypass -File verify.ps1

It builds a small fixture tree in %TEMP%, then checks the JSON output shape, aggregation behaviour, argument handling and error exit codes.

CI runs build.ps1 followed by verify.ps1 on every push and pull request.

Usage

Download the prebuilt DiskTreemap.exe from the latest release, or build it yourself with build.ps1. Then run it to open the picker, or pass a root to go straight to the viewer:

.\DiskTreemap.exe                     # open the drive / folder picker
.\DiskTreemap.exe "C:\Users"
.\DiskTreemap.exe "D:\" --min 10485760
.\DiskTreemap.exe "D:\Projects" --out tree.json
.\DiskTreemap.exe --help

Options:

Option	Meaning
--out <file> / -o	Scan only, write the JSON tree to a file and exit (no window). A root directory must be given explicitly.
--min <bytes> / --min-file	Aggregation threshold (default 1048576). 0 disables aggregation. With no root it presets the threshold in the picker.
--help / -h / /?	Show help.

The exit code is 2 on a usage or scan error, 0 otherwise.

Keyboard shortcuts

Key	Action
Backspace	Go to the parent folder
Alt + ←	Back (history)
F5	Rescan the current root
Ctrl + C	Copy the full path of the selected cell

Mouse: drag to pan, wheel to zoom, double-click a folder cell to enter it, double-click a file to open it when it already sits directly in the current folder (otherwise the view jumps to the folder that contains it), and right-click any cell for the native action menu. Right-clicking empty canvas space opens a small menu with fit / rescan / pick path. Drag any edge or corner of the borderless window to resize it.

Design notes

• Squarified treemap — TreemapLayout.Squarify lays children out by area while keeping aspect ratios near 1, so labels stay readable.
• Sharp, shared edges — cells use square corners and ~1 px borders so siblings sit flush against each other, SpaceSniffer style.
• Two view scales — entering a folder fills the viewport 1:1; 适应 (fit) drops to ~0.8 and centres the map for comfortable breathing room.
• Labels degrade gracefully — a cell is labelled name size; when that does not fit, the size is dropped so the full folder name stays readable in narrow columns instead of being cut to Reso….
• Theme is centralised — Palette holds a light and a dark colour set; Theme holds the accent colour and chrome colours. Switching the theme re-applies both to the canvas, toolbar renderer, status bar and menus.
• Localisation — one Loc table maps the Chinese source strings to English; the language is chosen once at startup from the Windows UI language, and any string without a translation falls back to Chinese.
• DPI aware (system) — the process calls SetProcessDPIAware() and derives the treemap header height from the font metrics, so text stays sharp and unclipped on scaled displays. Per-monitor DPI is not implemented: WinForms on .NET Framework 4.x has no per-monitor support, so on mixed-DPI setups the window keeps the scale of the monitor it started on.
• Borderless resizing — the docked children (title bar, canvas, status bar) return HTTRANSPARENT in the 6 px border zone so WM_NCHITTEST reaches the form and all eight resize directions work.
• Native directory enumeration — the scanner keeps DirectoryInfo / FileInfo out of the hot path and reads WIN32_FIND_DATA straight from FindFirstFileEx. On a full C:\Windows (310 k files / 148 k directories) this took a scan from ~39 s down to ~6.5 s.
• Streaming JSON — --out writes node by node straight to the file rather than building the whole document in memory, and the scanner releases its directory dictionary and the walk tree as it converts to the node tree.
• Long paths — the manifest declares longPathAware, so paths beyond MAX_PATH are scanned on systems where the LongPathsEnabled policy is on (Windows 10 1607+). Elsewhere they are skipped and counted like any other unreadable entry. Moving such a path to the Recycle Bin still fails, because SHFileOperation does not accept long paths.

Antivirus false positives

The binary is not code-signed, so a few heuristic / machine-learning engines may flag a fresh build. Verdicts such as ML.Attribute.HighConfidence, Malicious.high.ml.score, Malicious (high Confidence) or *.susgen are generic ML scores aimed at new, unsigned, low-prevalence binaries — they do not name a malware family. Compiled-on-demand tools that carry version info but no signature tend to collect this kind of hit, and some engines are known for flagging freshly compiled programs in general.

If you would rather not trust the prebuilt binary attached to a release, build it yourself: the whole program is one C# file, and build.ps1 needs nothing beyond the compiler that ships with Windows. Each release also publishes a SHA-256 checksum of the executable so you can verify the download.

License

MIT — see LICENSE.