When supplying colors to Chart options, you can use a number of formats. You can specify the color as a string in hexadecimal, RGB, or HSL notations. If a color is needed, but not specified, Chart.js will use the global default color. This color is stored at Chart.defaults.global.defaultColor. It is initially set to 'rgba(0, 0, 0, 0.1)'. You can also pass a CanvasGradient object. You will need to create this before passing to the chart, but using it you can achieve some interesting effects.
val of_string : string -> t Js_of_ocaml.Js.tval of_canvas_gradient :
Js_of_ocaml.Dom_html.canvasGradient Js_of_ocaml.Js.t ->
t Js_of_ocaml.Js.tval of_canvas_pattern :
Js_of_ocaml.Dom_html.canvasPattern Js_of_ocaml.Js.t ->
t Js_of_ocaml.Js.tval cast_string : t Js_of_ocaml.Js.t -> string Js_of_ocaml.Js.optval cast_canvas_gradient :
t Js_of_ocaml.Js.t ->
Js_of_ocaml.Dom_html.canvasGradient Js_of_ocaml.Js.t Js_of_ocaml.Js.optval cast_canvas_pattern :
t Js_of_ocaml.Js.t ->
Js_of_ocaml.Dom_html.canvasPattern Js_of_ocaml.Js.t Js_of_ocaml.Js.opt