TC Screen Ruler

TC Screen Ruler is a precision desktop pixel measurement, color-tolerance edge-detection raycasting, and physical display DPI inspection utility for Linux.
An independent Linux alternative inspired by PowerToys Screen Ruler, it enables designers, frontend engineers, QA testers, and desktop users to measure exact pixel spans and physical dimensions directly on live desktop captures or reference images.

Key Features:
- Live Desktop & Reference Image Canvas: Captures the active Linux desktop via QScreen.grabWindow(0), loads any local PNG/JPEG/BMP/WebP image, or renders a precision DPI calibration grid sized to the real connected monitor.
- Four Interactive Ruler Modes: Measure elements with Horizontal, Vertical, 4-Way Crosshair, and interactive Bounding-Box pixel rulers with top and left graduated scales.
- Automatic Color-Tolerance Edge-Detection Raycast: Casts pixel-accurate rays Left, Right, Up, and Down from the cursor with adjustable Euclidean RGB color tolerance (0-120) to snap automatically to UI borders, margins, buttons, and layout containers.
- Real Physical Display DPI Conversion: Reads live QApplication.screens() geometry, logical/physical DPI, refresh rate, and Linux kernel /sys/class/drm connector telemetry to convert pixels accurately into millimeters (mm), inches (in), and typographic points (pt).
- Live 9x9 Pixel Loupe & Pinned Measurement Log: Inspect magnified cursor pixels with HEX/RGB color readouts, pin multiple measurements onto the canvas, scan local image dimensions, export CSV/JSON/TXT measurement tables, and export crisp annotated PNG images.
- Bilingual Interface: Instant one-click toggle between Vietnamese and English.

Disclaimer: This project is an independent open-source utility built by TC Studio and is not affiliated with, sponsored by, or endorsed by Microsoft Corporation.