lars verspohl

@larsvers·3 public vizzes

d3 and canvas - the bind, the draw and the pick

This example demonstrates how d3 and Canvas can work together for interactive visualization, showing 5,000 colored grid cells arranged in a 10x10 group layout. The code uses d3.v4 to bind data to custom DOM elements, applying sequential color scales with d3.interpolateSpectral. Rendering happens through a main canvas while a hidden canvas uses unique generated RGB colors and a color-to-node map for picking interactions. A tooltip appears on hover, and d3.timer animates cell widths during transitions, with optional React integration via VizHub.

Sep 29, 2026

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d3 and canvas - the bind and the draw

This example demonstrates how D3’s data join can drive canvas rendering through a custom HTML element as an intermediate container. The visualization displays a grid of colored cells, with the number of cells controlled by a text input, and animates their appearance. The code binds data to custom elements using D3’s `selectAll`, `enter`, and `merge`, then draws each cell’s position and fill style onto a 2D canvas context, using a `d3.scaleSequential` color scale and `d3.timer` for animation.

Apr 11, 2022

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d3 and canvas

D3 version 4 and the HTML5 Canvas API draw animated, colored grids of cells whose count is set by user input between 1 and 10,000. The code binds data to custom DOM elements, using transitions to animate cell size and fillStyle, then a d3.timer repeatedly invokes a draw function that clears and repaints the canvas. A d3.scaleSequential with d3.interpolateSpectral maps data values to colors.

Apr 11, 2022