kegashin/mantle

Mantle is a browser-based tool for turning screenshots and videos into polished promotional images. You import a screenshot, image, or video file, wrap it in a styled frame, set a background, optionally add text, and export a finished visual ready for social media posts, product launches, app store listings, or documentation. The tool runs entirely in the browser with no server upload involved, your media stays on your machine. Export also happens client-side, and saved style presets are stored in your browser's local storage. The visual options are broad. Built-in backgrounds include solid colors, gradients, marbling, smoke effects, glyph fields, scanlines, contour lines, and dot grids, with an option to use your own custom backdrop. Frames can simulate browser windows, terminal windows, code editors, document layouts, or appear frameless. Frame surfaces can be solid or glass-style, with controls for spacing, corner radius, shadow, and chrome. Editing is non-destructive, meaning you can adjust placement, scale, crop, and rotation at any time without damaging the original. Video sources are supported with motion preview and trim controls. Exports can include audio from source video. Output formats include PNG, JPEG, WebP, GIF, MP4, and WebM. PNG can also be copied directly to the clipboard when the browser permits it. The project is written in TypeScript and uses React 19 and Vite for the editor UI, with a canvas-based rendering engine kept separate from the UI layer so rendering logic can be shared across preview, export, and potential future automation surfaces. It runs locally using Bun and is licensed under Apache 2.0.