Free, open-source reference board for Android.
Website: https://iurika-n-t-r.github.io/DroRef/
Inspired by PureRef. DroRef is an independent app written from scratch and is not affiliated with PureRef or Idyllic Pixel. On PC, use the original: https://www.pureref.com
Boards move between the two as .pur files: File → Open .pur, Save, Save as .pur.
From PureRef 2, save with Save as → Legacy PureRef scene first.
- The canvas fills the screen (dot background by default; grid or plain in the menu, under View). Round buttons: menu and scene name top-left, undo, redo and focus mode top-right, add bottom-right.
- The menu is a panel of icon tiles grouped by purpose (Add, Board, File, View); search, settings and about sit in its header.
- Add images and videos from the gallery, paste them, paste a link, use Share → DroRef, or drag and drop them from another app (gallery, browser, files) in split screen: they land where you drop them.
- To drag an image out to another app, select it, then long-press it again and drag.
- Drag empty space to pan, pinch to zoom, double-tap to focus.
- Tap to select. Drag to move; pinch or twist with two fingers to scale and rotate.
- Long-press an item to add it to the selection. Long-press empty space and drag to select a rectangle; release without dragging for the canvas panel.
- What's selected gets a short toolbar of icons (long-press one to see its name); "more" opens everything else, grouped: Transform, Arrange, Align, Size, Layers & groups, Item.
- My scenes (tap the scene name, or Ctrl+Alt+L) shows every scene as a preview; long-press one to rename it or move it into a folder. Ctrl+Shift+L jumps back to the previous scene.
- Always on top floats the board over your drawing app. Its bar has opacity, transparent-to-touch (for tracing), background off (only the images float), and a pin to show it only over one app (Android asks once for usage access).
Everything PureRef has, and what's done here: FEATURES.md
With a tablet keyboard cover, a Bluetooth keyboard and mouse, or a Chromebook, DroRef works like PureRef on a PC: same default shortcuts, same mouse controls. Ctrl+H (or the keyboard button in the menu) opens a short guide in the app; Meta+/ lists every shortcut. The first time a keyboard is connected, DroRef points to the guide.
| Mouse | |
|---|---|
| Left-drag on empty space | Select (Shift adds to the selection) |
| Left-click / drag an item | Select / move it (Shift-click adds, Shift-drag moves in a straight line) |
| Ctrl-drag | Rotate (Ctrl+Shift: 45° steps) |
| Ctrl+Alt-drag | Scale |
| Middle-, right- or Alt-drag | Pan |
| Right-click | Menu for the item, or the canvas |
| Wheel | Zoom |
| Touchpad | Two-finger swipe pans, pinch zooms, Ctrl + swipe zooms |
| Keys | |
|---|---|
| Ctrl+Z / Ctrl+Shift+Z | Undo / redo |
| Ctrl+C / X / V, Ctrl+D, Del | Copy / cut / paste, duplicate, delete |
| Ctrl+I, Ctrl+N, Ctrl+Shift+D | Add images, note, draw |
| Space, Ctrl+Space, ← → | Focus selection, focus canvas, previous / next |
| Ctrl+P, Ctrl+Alt+N / A / O / D / R | Arrange optimal, by name / addition / order / path / randomly |
| Ctrl+arrows, Ctrl+Alt+arrows | Align, normalize |
| Alt+Shift+H / V, Ctrl+Shift+T | Flip, reset transform |
| Ctrl+G / Ctrl+Shift+G, P, ↑ ↓ | Group / ungroup, parent, front / back |
| Ctrl+K, Ctrl+Alt+L, Ctrl+Shift+L | New scene, my scenes, previous scene |
| Ctrl+S / Ctrl+Shift+S, Ctrl+L | Save / save as .pur, open .pur |
| Ctrl+Shift+P | Command palette |
Open this folder in Android Studio and press Run, or from a terminal:
./gradlew assembleDebug
The APK lands in app/build/outputs/apk/debug/.
Test the .pur reader and writer:
./gradlew testDebugUnitTest -PpurDir=/tmp/pur
That writes kt_edit.pur into the folder. Check it with real PureRef: PureRef -c 'load;/tmp/pur/kt_edit.pur' -c 'exportScene;/tmp/pur/out.png' -c exit
The launcher icon comes from art/icon.png: run python3 -I tools/icon.py to regenerate every size.
Translations live in one table, tools/strings.py. Edit it and run python3 tools/strings.py to regenerate every strings.xml.
tools/ui.py drives an emulator for quick UI checks (tap by label, screenshot).
Download the APK from Releases, or build it:
./gradlew assembleRelease # signed APK -> app/build/outputs/apk/release/
./gradlew bundleRelease # signed AAB for Google Play -> app/build/outputs/bundle/release/
Signing reads keystore.properties (git-ignored): storeFile, storePassword, keyAlias, keyPassword.
Without it, release builds are unsigned, which is what F-Droid expects (it signs with its own key).
Store listing text and screenshots for F-Droid live in fastlane/metadata/android/.
DroRef is built and maintained solo and stays free. If it helps you, consider buying me a coffee ☕
.purformat: ported from FyorDev/PureRef-format (MIT)- Video loops idea: lettucegoblin/AnimRef (MIT)
- Icons: Lucide (ISC, see
third_party/LUCIDE_LICENSE.txt);tools/icons.pyconverts them
MIT