feat: support domainRaw so one may bind domainRaw to a parameter to build custom interaction

build/vega-lite-schema.json

@@ -21739,6 +21739,10 @@
           ],
           "description": "Sets the minimum value in the scale domain, overriding the domain property. This property is only intended for use with scales having continuous domains."
         },
+        "domainRaw": {
+          "$ref": "#/definitions/ExprRef",
+          "description": "An expression for an array of raw values that, if non-null, directly overrides the _domain_ property. This is useful for supporting interactions such as panning or zooming a scale. The scale may be initially determined using a data-driven domain, then modified in response to user input by setting the rawDomain value."
+        },
         "exponent": {
           "anyOf": [
             {

examples/compiled/interactive_point_domainRaw_binding.vg.json

@@ -0,0 +1,148 @@
+{
+  "$schema": "https://vega.github.io/schema/vega/v5.json",
+  "background": "white",
+  "padding": 5,
+  "width": 200,
+  "height": 200,
+  "style": "cell",
+  "data": [
+    {
+      "name": "source_0",
+      "url": "data/cars.json",
+      "format": {"type": "json"},
+      "transform": [
+        {
+          "type": "filter",
+          "expr": "isValid(datum[\"Horsepower\"]) && isFinite(+datum[\"Horsepower\"]) && isValid(datum[\"Miles_per_Gallon\"]) && isFinite(+datum[\"Miles_per_Gallon\"]) && isValid(datum[\"Cylinders\"]) && isFinite(+datum[\"Cylinders\"])"
+        }
+      ]
+    }
+  ],
+  "signals": [
+    {
+      "name": "min_x",
+      "value": 50,
+      "bind": {"input": "range", "min": 0, "max": 300}
+    },
+    {
+      "name": "max_x",
+      "value": 250,
+      "bind": {"input": "range", "min": 0, "max": 300}
+    },
+    {"name": "use_custom_x", "value": true, "bind": {"input": "checkbox"}}
+  ],
+  "marks": [
+    {
+      "name": "marks",
+      "type": "symbol",
+      "clip": true,
+      "style": ["circle"],
+      "from": {"data": "source_0"},
+      "encode": {
+        "update": {
+          "opacity": {"value": 0.7},
+          "fill": {"value": "#4c78a8"},
+          "ariaRoleDescription": {"value": "circle"},
+          "description": {
+            "signal": "\"Horsepower: \" + (format(datum[\"Horsepower\"], \"\")) + \"; Miles_per_Gallon: \" + (format(datum[\"Miles_per_Gallon\"], \"\")) + \"; Cylinders: \" + (format(datum[\"Cylinders\"], \"\"))"
+          },
+          "x": {"scale": "x", "field": "Horsepower"},
+          "y": {"scale": "y", "field": "Miles_per_Gallon"},
+          "size": {"scale": "size", "field": "Cylinders"},
+          "shape": {"value": "circle"}
+        }
+      }
+    }
+  ],
+  "scales": [
+    {
+      "name": "x",
+      "type": "linear",
+      "domain": {"data": "source_0", "field": "Horsepower"},
+      "range": [0, {"signal": "width"}],
+      "domainRaw": {"signal": "use_custom_x ? [min_x, max_x] : null"},
+      "nice": true,
+      "zero": true
+    },
+    {
+      "name": "y",
+      "type": "linear",
+      "domain": {"data": "source_0", "field": "Miles_per_Gallon"},
+      "range": [{"signal": "height"}, 0],
+      "nice": true,
+      "zero": true
+    },
+    {
+      "name": "size",
+      "type": "linear",
+      "domain": {"data": "source_0", "field": "Cylinders"},
+      "range": [0, 361],
+      "zero": true
+    }
+  ],
+  "axes": [
+    {
+      "scale": "x",
+      "orient": "bottom",
+      "gridScale": "y",
+      "grid": true,
+      "tickCount": {"signal": "ceil(width/40)"},
+      "domain": false,
+      "labels": false,
+      "aria": false,
+      "maxExtent": 0,
+      "minExtent": 0,
+      "ticks": false,
+      "zindex": 0
+    },
+    {
+      "scale": "y",
+      "orient": "left",
+      "gridScale": "x",
+      "grid": true,
+      "tickCount": {"signal": "ceil(height/40)"},
+      "domain": false,
+      "labels": false,
+      "aria": false,
+      "maxExtent": 0,
+      "minExtent": 0,
+      "ticks": false,
+      "zindex": 0
+    },
+    {
+      "scale": "x",
+      "orient": "bottom",
+      "grid": false,
+      "title": "Horsepower",
+      "labelFlush": true,
+      "labelOverlap": true,
+      "tickCount": {"signal": "ceil(width/40)"},
+      "zindex": 0
+    },
+    {
+      "scale": "y",
+      "orient": "left",
+      "grid": false,
+      "title": "Miles_per_Gallon",
+      "labelOverlap": true,
+      "tickCount": {"signal": "ceil(height/40)"},
+      "zindex": 0
+    }
+  ],
+  "legends": [
+    {
+      "size": "size",
+      "symbolType": "circle",
+      "title": "Cylinders",
+      "encode": {
+        "symbols": {
+          "update": {
+            "fill": {"value": "#4c78a8"},
+            "opacity": {"value": 0.7},
+            "stroke": {"value": "transparent"}
+          }
+        }
+      }
+    }
+  ]
+}

examples/specs/interactive_point_domainRaw_binding.vl.json

@@ -0,0 +1,40 @@
+{
+  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
+  "data": {"url": "data/cars.json"},
+  "params": [{
+    "name": "min_x",
+    "value": 50,
+    "bind": {
+      "input": "range",
+      "min": 0,
+      "max": 300
+    }
+  }, {
+    "name": "max_x",
+    "value": 250,
+    "bind": {
+      "input": "range",
+      "min": 0,
+      "max": 300
+    }
+  },{
+    "name": "use_custom_x",
+    "value": true,
+    "bind": {
+      "input": "checkbox"
+    }
+  }],
+  "mark": {"type": "circle", "clip": true},
+  "encoding": {
+    "x": {
+      "field": "Horsepower", "type": "quantitative",
+      "scale": {
+        "domainRaw": {"expr": "use_custom_x ? [min_x, max_x] : null"}
+      }
+    },
+    "y": {
+      "field": "Miles_per_Gallon", "type": "quantitative"
+    },
+    "size": {"field": "Cylinders", "type": "quantitative"}
+  }
+}

site/docs/encoding/scale.md

@@ -75,7 +75,7 @@ bar, image, rect, and rule marks while `"point"` is the default scales for all o
 
 By default, a scale in Vega-Lite draws domain values directly from a channel's encoded field. Users can specify the `domain` property of a scale to customize its domain values. To sort the order of the domain of the encoded, the [`sort`](sort.html) property of a [field definition](encoding.html#field-def) can be specified.
 
-{% include table.html props="domain,domainMax,domainMin,domainMid" source="Scale" %}
+{% include table.html props="domain,domainMax,domainMin,domainMid,domainRaw" source="Scale" %}
 
 A common use case for the `domain` property is to limit, for example, the `x` range of values to include in a plot. However, setting the domain property alone is insufficient to achieve the desired effect.
 
@@ -101,6 +101,10 @@ There are two approaches to keep the mark from being plotted outside the desired
 
 <div class="vl-example" data-name="line_inside_domain_using_transform"></div>
 
+### Example: Using `domainRaw` to bind domain interactively
+
+<div class="vl-example" data-name="interactive_point_domainRaw_binding"></div>
+
 <!--
 #### Example: Custom Domain
 TODO: Custom Domain for quantitative / discrete scales

src/compile/scale/component.ts

@@ -11,7 +11,7 @@ import {Explicit, Split} from '../split';
  * All VgDomain property except domain.
  * (We exclude domain as we have a special "domains" array that allow us merge them all at once in assemble.)
  */
-export type ScaleComponentProps = Omit<VgScale, 'domain' | 'domainRaw' | 'reverse'> & {
+export type ScaleComponentProps = Omit<VgScale, 'domain' | 'reverse'> & {
   domains: VgNonUnionDomain[];
   selectionExtent?: ParameterExtent;
   reverse?: boolean | SignalRef; // Need override since Vega doesn't official support scale reverse yet (though it does in practice)

src/scale.ts

@@ -546,6 +546,13 @@ export interface Scale<ES extends ExprRef | SignalRef = ExprRef | SignalRef> {
     | DomainUnionWith
     | ES;
 
+  /**
+   * An expression for an array of raw values that, if non-null, directly overrides the _domain_ property.
+   * This is useful for supporting interactions such as panning or zooming a scale.
+   * The scale may be initially determined using a data-driven domain, then modified in response to user input by setting the rawDomain value.
+   */
+  domainRaw?: ES;
+
   /**
    * Inserts a single mid-point value into a two-element domain. The mid-point value must lie between the domain minimum and maximum values. This property can be useful for setting a midpoint for [diverging color scales](https://vega.github.io/vega-lite/docs/scale.html#piecewise). The domainMid property is only intended for use with scales supporting continuous, piecewise domains.
    */
@@ -728,6 +735,7 @@ const SCALE_PROPERTY_INDEX: Flag<keyof Scale<any>> = {
   domainMax: 1,
   domainMin: 1,
   domainMid: 1,
+  domainRaw: 1,
   align: 1,
   range: 1,
   rangeMax: 1,
@@ -785,6 +793,7 @@ export function scaleTypeSupportProperty(scaleType: ScaleType, propName: keyof S
     case 'domainMax':
     case 'domainMid':
     case 'domainMin':
+    case 'domainRaw':
     case 'clamp':
       return isContinuousToContinuous(scaleType);
     case 'nice':
@@ -830,6 +839,7 @@ export function channelScalePropertyIncompatability(channel: Channel, propName:
     case 'domain':
     case 'domainMax':
     case 'domainMin':
+    case 'domainRaw':
     case 'range':
     case 'base':
     case 'exponent':