Zoomable Circle Packing with Canvas & D3.js - I
This example visualizes the hierarchical structure of occupational data through a zoomable circle packing layout, where nested circles represent job categories and their sizes correspond to employment counts. The visualization uses D3.js for data binding and layout computation via `d3.layout.pack`, while all rendering occurs on an HTML5 Canvas element. A hidden second canvas, where each circle receives a unique color, enables click-based selection and zooming through color-to-node lookup in a dictionary. The animation zooms between hierarchy levels, though the transition remains jittery and requires a hybrid approach to manage performance.