diff --git a/examples/compiled/bar_grouped_discrete_bandsize.png b/examples/compiled/bar_grouped_discrete_bandsize.png
new file mode 100644
index 0000000000..d46950f8ca
Binary files /dev/null and b/examples/compiled/bar_grouped_discrete_bandsize.png differ
diff --git a/examples/compiled/bar_grouped_discrete_bandsize.svg b/examples/compiled/bar_grouped_discrete_bandsize.svg
new file mode 100644
index 0000000000..a32110aec9
--- /dev/null
+++ b/examples/compiled/bar_grouped_discrete_bandsize.svg
@@ -0,0 +1 @@
+
\ No newline at end of file
diff --git a/examples/compiled/bar_grouped_discrete_bandsize.vg.json b/examples/compiled/bar_grouped_discrete_bandsize.vg.json
new file mode 100644
index 0000000000..76916e641c
--- /dev/null
+++ b/examples/compiled/bar_grouped_discrete_bandsize.vg.json
@@ -0,0 +1,142 @@
+{
+ "$schema": "https://vega.github.io/schema/vega/v5.json",
+ "background": "white",
+ "padding": 5,
+ "height": 200,
+ "style": "cell",
+ "data": [
+ {
+ "name": "source_0",
+ "values": [
+ {"category": "A", "group": "x", "value": 0.1},
+ {"category": "A", "group": "y", "value": 0.6},
+ {"category": "A", "group": "z", "value": 0.9},
+ {"category": "B", "group": "x", "value": 0.7},
+ {"category": "B", "group": "y", "value": 0.2},
+ {"category": "B", "group": "z", "value": 1.1},
+ {"category": "C", "group": "x", "value": 0.6},
+ {"category": "C", "group": "y", "value": 0.1},
+ {"category": "C", "group": "z", "value": 0.2}
+ ]
+ },
+ {
+ "name": "data_0",
+ "source": "source_0",
+ "transform": [
+ {
+ "type": "stack",
+ "groupby": ["category", "group"],
+ "field": "value",
+ "sort": {"field": [], "order": []},
+ "as": ["value_start", "value_end"],
+ "offset": "zero"
+ },
+ {
+ "type": "filter",
+ "expr": "isValid(datum[\"value\"]) && isFinite(+datum[\"value\"])"
+ }
+ ]
+ }
+ ],
+ "signals": [
+ {
+ "name": "x_step",
+ "update": "20 * bandspace(domain('xOffset').length, 0, 0) / (1-0.2)"
+ },
+ {
+ "name": "width",
+ "update": "bandspace(domain('x').length, 0.2, 0.2) * x_step"
+ }
+ ],
+ "marks": [
+ {
+ "name": "marks",
+ "type": "rect",
+ "style": ["bar"],
+ "from": {"data": "data_0"},
+ "encode": {
+ "update": {
+ "fill": {"scale": "color", "field": "group"},
+ "ariaRoleDescription": {"value": "bar"},
+ "description": {
+ "signal": "\"category: \" + (isValid(datum[\"category\"]) ? datum[\"category\"] : \"\"+datum[\"category\"]) + \"; value: \" + (format(datum[\"value\"], \"\")) + \"; group: \" + (isValid(datum[\"group\"]) ? datum[\"group\"] : \"\"+datum[\"group\"])"
+ },
+ "x": {
+ "scale": "x",
+ "field": "category",
+ "offset": {"scale": "xOffset", "field": "group", "band": 0.25}
+ },
+ "width": {"signal": "max(0.25, 0.5 * bandwidth('xOffset'))"},
+ "y": {"scale": "y", "field": "value_end"},
+ "y2": {"scale": "y", "field": "value_start"}
+ }
+ }
+ }
+ ],
+ "scales": [
+ {
+ "name": "x",
+ "type": "band",
+ "domain": {"data": "data_0", "field": "category", "sort": true},
+ "range": {"step": {"signal": "x_step"}},
+ "paddingInner": 0.2,
+ "paddingOuter": 0.2
+ },
+ {
+ "name": "y",
+ "type": "linear",
+ "domain": {"data": "data_0", "fields": ["value_start", "value_end"]},
+ "range": [{"signal": "height"}, 0],
+ "nice": true,
+ "zero": true
+ },
+ {
+ "name": "xOffset",
+ "type": "band",
+ "domain": {"data": "data_0", "field": "group", "sort": true},
+ "range": {"step": 20}
+ },
+ {
+ "name": "color",
+ "type": "ordinal",
+ "domain": {"data": "data_0", "field": "group", "sort": true},
+ "range": "category"
+ }
+ ],
+ "axes": [
+ {
+ "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": "category",
+ "labelAlign": "right",
+ "labelAngle": 270,
+ "labelBaseline": "middle",
+ "zindex": 0
+ },
+ {
+ "scale": "y",
+ "orient": "left",
+ "grid": false,
+ "title": "value",
+ "labelOverlap": true,
+ "tickCount": {"signal": "ceil(height/40)"},
+ "zindex": 0
+ }
+ ],
+ "legends": [{"fill": "color", "symbolType": "square", "title": "group"}]
+}
diff --git a/examples/specs/bar_grouped_discrete_bandsize.vl.json b/examples/specs/bar_grouped_discrete_bandsize.vl.json
new file mode 100644
index 0000000000..f18a359829
--- /dev/null
+++ b/examples/specs/bar_grouped_discrete_bandsize.vl.json
@@ -0,0 +1,26 @@
+{
+ "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
+ "data": {
+ "values": [
+ {"category":"A", "group": "x", "value":0.1},
+ {"category":"A", "group": "y", "value":0.6},
+ {"category":"A", "group": "z", "value":0.9},
+ {"category":"B", "group": "x", "value":0.7},
+ {"category":"B", "group": "y", "value":0.2},
+ {"category":"B", "group": "z", "value":1.1},
+ {"category":"C", "group": "x", "value":0.6},
+ {"category":"C", "group": "y", "value":0.1},
+ {"category":"C", "group": "z", "value":0.2}
+ ]
+ },
+ "mark": "bar",
+ "encoding": {
+ "x": {"field": "category"},
+ "y": {"field": "value", "type": "quantitative"},
+ "xOffset": {"field": "group"},
+ "color": {"field": "group"}
+ },
+ "config": {
+ "bar": {"discreteBandSize": {"band": 0.5}}
+ }
+}
diff --git a/src/compile/mark/encode/offset.ts b/src/compile/mark/encode/offset.ts
index 0ee51be1d2..b2da454a74 100644
--- a/src/compile/mark/encode/offset.ts
+++ b/src/compile/mark/encode/offset.ts
@@ -26,7 +26,7 @@ export function positionOffset({
markDef: MarkDef;
encoding?: Encoding;
model?: UnitModel;
- bandPosition?: number;
+ bandPosition?: number | SignalRef;
}): Offset {
const channel = `${baseChannel}Offset` as
| 'xOffset'
diff --git a/src/compile/mark/encode/position-rect.ts b/src/compile/mark/encode/position-rect.ts
index 634696f717..e34f54d62e 100644
--- a/src/compile/mark/encode/position-rect.ts
+++ b/src/compile/mark/encode/position-rect.ts
@@ -209,7 +209,16 @@ function positionAndSize(
const vgChannel = vgAlignedPositionChannel(channel, markDef, config, defaultBandAlign);
const center = vgChannel === 'xc' || vgChannel === 'yc';
- const {offset, offsetType} = positionOffset({channel, markDef, encoding, model, bandPosition: center ? 0.5 : 0});
+
+ const bandPosition = center
+ ? 0.5
+ : isSignalRef(bandSize)
+ ? {signal: `(1-${bandSize})/2`}
+ : isRelativeBandSize(bandSize)
+ ? (1 - bandSize.band) / 2
+ : 0;
+
+ const {offset, offsetType} = positionOffset({channel, markDef, encoding, model, bandPosition});
const posRef = ref.midPointRefWithPositionInvalidTest({
channel,
@@ -221,15 +230,7 @@ function positionAndSize(
stack,
offset,
defaultRef: pointPositionDefaultRef({model, defaultPos: 'mid', channel, scaleName, scale}),
- bandPosition: center
- ? offsetType === 'encoding'
- ? 0
- : 0.5
- : isSignalRef(bandSize)
- ? {signal: `(1-${bandSize})/2`}
- : isRelativeBandSize(bandSize)
- ? (1 - bandSize.band) / 2
- : 0
+ bandPosition: offsetType === 'encoding' ? 0 : bandPosition
});
if (vgSizeChannel) {