H5P Resizer JS

This tool analyzes a target hosting container and yields dimension rules for H5P content blocks that ensure the content fits without overflow while preserving interactivity. It is intended for developers, instructional designers, and course authors who embed H5P activities in responsive LMS pages and learning portals. When a page layout requires a consistent H5P size across breakpoints or when content is either too large for a container or leaves excessive whitespace, the tool provides integration-ready measurements and code snippets that do not modify H5P assets themselves.
The core operation uses a fit-to-container approach: given container_width and container_height and an optional aspect_ratio, it computes a single scale factor and applies it to the H5P block's base dimensions. If aspect_ratio is provided, the tool enforces final dimensions to match that ratio, then recalculates the scale to minimize distortion. Optional constraints (min_width, max_width, min_height, max_height) constrain the result. The tool can export a CSS snippet and, optionally, a lightweight JavaScript hook that re-applies sizing on resize events. It preserves the interactive surface while delivering deterministic rendering.
Typical use cases include uniform cards in course catalogs, dashboards showing several activities, and modules embedded in other content blocks. The unique value is the automatic generation of embedding-ready rules that practitioners can paste or attach to a page without manual calculations. It supports future extensions such as height auto-adjustment, DPI-aware scaling, or per-activity presets, while maintaining a narrow scope focused on container-fit and aspect preservation.