deltip

Discount calculator. VAT splitter. Clipboard-first. Personal tool - built for one person's workflow.

Warning

Beta. The current version is tracked in gradle.properties (app.version). Public APIs and the settings schema may still change between releases.

Note

The UI ships German and English strings (since v0.3.0, via Compose Resources); German is the base locale. There is no in-app language switcher — the displayed language is whatever the system locale resolves to.

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What it does

Two modes, one field, zero friction.

Mode	Input	Output	Auto-copied
Rabatt (default)	gross price	discounted final price	final price
MwSt	gross amount	net + VAT share	VAT amount

Both modes accept 12,50 and 12.50 interchangeably. Auto-copy fires 300 ms after the last keystroke - no button needed.

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Usage

1. App opens - input field is already focused.
2. Switch mode with the Rabatt / MwSt toggle if needed.
3. Type a value, e.g. 49,99.
4. Read the result. Shortly after, it lands in your clipboard.
5. Click the field to clear it and start over.

Settings (discount %, VAT %, currency symbol, Vorne, Autostart) persist across restarts.
Since v0.2.0: the desktop window remembers its last position.

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Build

Requires: JDK 21 (Eclipse Temurin or compatible), Git.

git clone https://github.com/inventory69/deltip.git
cd deltip

./gradlew :composeApp:run                              # desktop
./gradlew :composeApp:assembleDebug                    # Android APK
./gradlew :composeApp:packageDistributionForCurrentOS  # native packages
./gradlew :composeApp:allTests                         # tests

Native packages land in composeApp/build/compose/binaries/main/.

Optional dependencies for native packages

• Linux (.deb / .rpm): fakeroot, rpm
• Windows (.exe): WiX Toolset 3.x

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Platform notes

	Linux	Windows	Android
Autostart	~/.config/autostart/deltip.desktop	HKCU\...\CurrentVersion\Run	-
Always on top	✓	✓	-
Dark mode title bar	-	✓ (v0.2.0+)	follows system

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New in v0.4.0

• Bidirectional VAT - split gross→net or gross up net→gross, with a quick 19/7 % selector and a swap button.
• Dedicated settings screen - always-on-top, autostart, VAT %, version and update controls moved off the main bar.
• Windows auto-update - the desktop app polls a GitHub Pages latest.json manifest (with a GitHub Releases API fallback) and installs new versions in place.

Shipped in v0.3.0

• i18n - English as a second language alongside German, via Compose Multiplatform resource strings, following the system locale.
• Signed Android APK - keystore signing in CI so GitHub releases ship a ready-to-install .apk.

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Contributing

Important

The UI is bilingual (German base + English). Commit messages and this README are English; code comments are German. When adding user-facing text, add the key to both values/strings.xml and values-en/strings.xml.

Before opening a PR:

• ./gradlew :composeApp:allTests must be green.
• Commit messages follow Conventional Commits - imperative, English, ≤ 72 chars.
• Platform-specific changes belong in the expect/actual bridges under commonMain/platform/ + <target>Main/platform/.

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Docs

Architecture, version matrix, constraints and implementation plans live in the private project-docs/deltip/ repo (developer_constraints.md, architektur.md, versions.md, impl-plan*.md).

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GPL-3.0-or-later - Fabian Dettmer, 2026.