LaBLEr1.4.0

Create label layouts on an Android phone and print them over Bluetooth Low Energy to Marklife-family thermal printers such as the P15, P12, and L13. Designs can be saved as reusable templates and printed again without an account, cloud service, or vendor app; the P15 has been verified on-device, while the P12 and L13 use the same protocol and a 12 mm, 96-dot print head. LaBLEr is open-source, runs on Android 8.0 or later, and supports arm64-v8a, armeabi-v7a, x86_64, and x86 devices.

Its editor handles multi-line text with sizing, bold, italic, underline, alignment, bundled fonts, and imported TTF or OTF files. Labels can include symbols, emoji, frames, images, and QR codes or barcodes in Code 128, EAN-13, UPC-A, Code 39, and ITF formats. Elements can be moved, resized, rotated, zoomed, and panned on the canvas, with snapping to centers, edges, and neighboring elements.

Images are converted for the printer’s 1-bit thermal head through outline rendering with region tracing or Canny edge detection, a smoothing pass, inversion, or threshold, Floyd-Steinberg, and Atkinson dithering. Users can save, rename, duplicate, favorite, and search templates, export single labels as JSON, and back up or restore the complete template library. Date, time, running-number, and free-text placeholders can be filled during printing, alongside an exact 1-bit preview, selection copying, die-cut or continuous-media choices, reproducible print history, and automatic reconnection to a saved printer.

Communication is local over Bluetooth Low Energy; LaBLEr declares no INTERNET permission, keeps templates, history, and settings in private app storage, and includes no analytics or tracking. Its Material 3 interface follows the system light or dark setting and is available in 17 languages. Version 1.4.0 adds half-millimetre margin fields for automatic label edges and makes variable labels follow their content evenly, while millimetre controls gain one-millimetre arrows and emptied text or code remains outlined in the editor.