The javascript hsl(hue, saturation, lightness) is not work as exepected. The hue should go from 0->360 however it seems Qt uses a char for hue thus our max value is 0->255. You can prove this using the following code:

In a Canvas in the onpaint() function:

ctx.strokeStyle = 'hsl(255, 100%, 50%)';
console.log("before = " + ctx.strokeStyle);
ctx.strokeStyle = 'hsl(320, 100%, 50%)';
console.log("after = " + ctx.strokeStyle)

You will notice you get the same #hex color out of it.