Gladly

A lightweight, GPU-accelerated plotting library with a declarative API.

Overview

Gladly combines WebGL rendering (via regl) with D3.js for interactive axes and zoom controls. It features a declarative API that lets you create high-performance plots with minimal boilerplate.

Key Features:

• 🚀 GPU-accelerated rendering using WebGL
• 💨 Zero JavaScript loops over data - all processing in GPU shaders
• 📊 Declarative plot configuration
• 🎯 Interactive multi-axis support (up to 4 axes)
• 🔍 Zoom and pan interactions
• 🧩 Extensible layer type registry
• 📏 Quantity and unit-aware axis management
• 🎨 Supports all standard colorscales
• 🔗 Subplot axis linking
• 🌈 Axis to coloring or filtering linking
• 🌎 GIS layers:
  • 🗺️ Tile sources: XYZ, WMS, WMTS, COG
  • 🌍 Basemap layer
  • 🏔️ 3D terrain layer: satellite imagery draped over DTM elevation meshes
  • 🌐 CRS reprojection

Extensions

• gladly-jupyter - Jupyter notebook widget extension for Gladly

Documentation

• Quick Start - Installation and minimal working example
• Concepts - Data model overview: axes, quantity kinds, colorscales, layer types, data format
• Configuration - Plot configuration, layers, axes, colorscales, built-in computations
• User API - Programmatic APIs for plots, axes, data, and computations
• Extension API - Writing custom layer types and computations
• Architecture - Design patterns and module responsibilities

Technology Stack

• WebGL Rendering: regl v2.1.0
• Axes & Interaction: D3.js v7.8.5
• Module Format: ES6 modules
• Build Tool: Parcel v2.9.0

Development

Install dependencies:

npm install

Run the test suite (launches a real Chromium browser via Playwright):

npm test

Tests live in test/. The pretest script pre-bundles CJS dependencies (regl, proj4) to ESM before the runner starts. On first run, Playwright downloads its Chromium binary automatically.

To run a subset of tests by name:

npm test -- --grep "uploadToTexture"

License

MIT