Image editor with ruler

This tool accepts an image file and renders measurement rulers along the top and left edges without altering the underlying pixels. It supports unit systems in pixels, inches, and centimeters, with configurable tick intervals and optional major/minor tick visibility. The ruler overlays are non-destructive and export with the edited image in a chosen format. Common use cases include pixel-perfect alignment verification, layout preflight, and print-ready sizing checks for assets. For example, upload a 2048x1536 image, set units to pixels, choose a 50-pixel tick interval, and export an annotated PNG.
Conceptually, the tool analyzes the image, derives a scale from the selected unit and DPI, and draws vector tick marks that align with the image canvas. It can also accept an optional crop region, producing an output where the ruler guides frame the selected area. Exports can be PNG or JPEG at a specified resolution, preserving the original image while embedding a precise measurement overlay. The workflow is designed for designers, QA engineers, and web developers who need verifiable dimensions directly within the edited asset.
Key differentiators include DPI-aware overlays, multi-unit support, and non-destructive, exportable ruler graphics. Advanced features may add color customization, density presets, and edge-aligned displays on both axes. Use cases span UI mockups, asset preflight, and production-ready imagery requiring exact measurements. The tool prioritizes accuracy, reproducibility, and privacy by keeping processing transparent and, when possible, client-side, producing consistent outputs across platforms.