fix: describe how to set a custom scheme by setting the range, reverts #9262

build/vega-lite-schema.json

@@ -21928,20 +21928,14 @@
             {
               "$ref": "#/definitions/ColorScheme"
             },
-            {
-              "items": {
-                "type": "string"
-              },
-              "type": "array"
-            },
             {
               "$ref": "#/definitions/SchemeParams"
             },
             {
               "$ref": "#/definitions/ExprRef"
             }
           ],
-          "description": "A string indicating a color [scheme](https://vega.github.io/vega-lite/docs/scale.html#scheme) name (e.g., `\"category10\"` or `\"blues\"`) or a [scheme parameter object](https://vega.github.io/vega-lite/docs/scale.html#scheme-params).\n\nDiscrete color schemes may be used with [discrete](https://vega.github.io/vega-lite/docs/scale.html#discrete) or [discretizing](https://vega.github.io/vega-lite/docs/scale.html#discretizing) scales. Continuous color schemes are intended for use with color scales.\n\nFor the full list of supported schemes, please refer to the [Vega Scheme](https://vega.github.io/vega/docs/schemes/#reference) reference."
+          "description": "A string indicating a color [scheme](https://vega.github.io/vega-lite/docs/scale.html#scheme) name (e.g., `\"category10\"` or `\"blues\"`) or a [scheme parameter object](https://vega.github.io/vega-lite/docs/scale.html#scheme-params).\n\nDiscrete color schemes may be used with [discrete](https://vega.github.io/vega-lite/docs/scale.html#discrete) or [discretizing](https://vega.github.io/vega-lite/docs/scale.html#discretizing) scales. Continuous color schemes are intended for use with color scales.\n\nTo set a custom scheme, instead set the list of values [as the scale range](https://vega.github.io/vega-lite/docs/scale.html#2-setting-the-range-property-to-an-array-of-valid-css-color-strings).\n\nFor the full list of supported schemes, please refer to the [Vega Scheme](https://vega.github.io/vega/docs/schemes/#reference) reference."
         },
         "type": {
           "$ref": "#/definitions/ScaleType",

src/compile/scale/range.ts

@@ -212,7 +212,7 @@ export function parseRangeForChannel(channel: ScaleChannel, model: UnitModel): E
   return makeImplicit(d);
 }
 
-function parseScheme(scheme: Scheme | SignalRef | string[]): RangeScheme {
+function parseScheme(scheme: Scheme | SignalRef): RangeScheme {
   if (isExtendedScheme(scheme)) {
     return {
       scheme: scheme.name,

src/scale.ts

@@ -481,7 +481,7 @@ export type Domain =
 
 export type Scheme = string | SchemeParams;
 
-export function isExtendedScheme(scheme: Scheme | SignalRef | string[]): scheme is SchemeParams {
+export function isExtendedScheme(scheme: Scheme | SignalRef): scheme is SchemeParams {
   return !isString(scheme) && !!scheme['name'];
 }
 
@@ -609,9 +609,11 @@ export interface Scale<ES extends ExprRef | SignalRef = ExprRef | SignalRef> {
    *
    * Discrete color schemes may be used with [discrete](https://vega.github.io/vega-lite/docs/scale.html#discrete) or [discretizing](https://vega.github.io/vega-lite/docs/scale.html#discretizing) scales. Continuous color schemes are intended for use with color scales.
    *
+   * To set a custom scheme, instead set the list of values [as the scale range](https://vega.github.io/vega-lite/docs/scale.html#2-setting-the-range-property-to-an-array-of-valid-css-color-strings).
+   *
    * For the full list of supported schemes, please refer to the [Vega Scheme](https://vega.github.io/vega/docs/schemes/#reference) reference.
    */
-  scheme?: ColorScheme | string[] | SchemeParams | ES;
+  scheme?: ColorScheme | SchemeParams | ES;
 
   /**
    * The alignment of the steps within the scale range.