How trading charts are built: the big products, read from their public docs, and the problems we met building TradeCanvas.
What we measured while giving TradeCanvas a WebGL renderer. A blend per canvas every frame, a stencil buffer nobody used, 19,200 rectangles, float32 rounding and a browser that quietly drops the sixteenth context.
Ichimoku plots its cloud 26 bars ahead of the price, where a chart has no bars, no times and no values. For a while TradeCanvas drew it under the price instead. What it took to put it where it belongs.
A trading chart puts a dozen tags on its price axis, and the interesting ones sit at the same price. How TradeCanvas lays them out so each stays readable, and the bugs that taught us where else they collide.
An open-source canvas library, a trading platform with its own language, and an SVG charting suite. What each one gives you, what it leaves to you, and the ideas worth borrowing, read from their public documentation.