fix: Area with plain quantitative fields on both axes get stacked by …

…default (vega#9018)

Co-authored-by: GitHub Actions Bot <[email protected]>

examples/compiled/area_cumulative_freq.vg.json

@@ -11,14 +11,37 @@
       "url": "data/movies.json",
       "format": {"type": "json", "parse": {"IMDB Rating": "number"}},
       "transform": [
+        {
+          "type": "aggregate",
+          "groupby": ["IMDB Rating"],
+          "ops": ["count"],
+          "fields": [null],
+          "as": ["count"]
+        },
         {
           "type": "window",
           "params": [null],
           "as": ["Cumulative Count"],
-          "ops": ["count"],
+          "ops": ["sum"],
           "fields": ["count"],
           "sort": {"field": ["IMDB Rating"], "order": ["ascending"]},
           "frame": [null, 0]
+        },
+        {
+          "type": "impute",
+          "field": "Cumulative Count",
+          "groupby": [],
+          "key": "IMDB Rating",
+          "method": "value",
+          "value": 0
+        },
+        {
+          "type": "stack",
+          "groupby": ["IMDB Rating"],
+          "field": "Cumulative Count",
+          "sort": {"field": [], "order": []},
+          "as": ["Cumulative Count_start", "Cumulative Count_end"],
+          "offset": "zero"
         }
       ]
     }
@@ -38,8 +61,8 @@
             "signal": "\"IMDB Rating: \" + (format(datum[\"IMDB Rating\"], \"\")) + \"; Cumulative Count: \" + (format(datum[\"Cumulative Count\"], \"\"))"
           },
           "x": {"scale": "x", "field": "IMDB Rating"},
-          "y": {"scale": "y", "field": "Cumulative Count"},
-          "y2": {"scale": "y", "value": 0},
+          "y": {"scale": "y", "field": "Cumulative Count_end"},
+          "y2": {"scale": "y", "field": "Cumulative Count_start"},
           "defined": {
             "signal": "isValid(datum[\"IMDB Rating\"]) && isFinite(+datum[\"IMDB Rating\"]) && isValid(datum[\"Cumulative Count\"]) && isFinite(+datum[\"Cumulative Count\"])"
           }
@@ -59,7 +82,10 @@
     {
       "name": "y",
       "type": "linear",
-      "domain": {"data": "source_0", "field": "Cumulative Count"},
+      "domain": {
+        "data": "source_0",
+        "fields": ["Cumulative Count_start", "Cumulative Count_end"]
+      },
       "range": [{"signal": "height"}, 0],
       "nice": true,
       "zero": true

examples/compiled/area_density.vg.json

@@ -16,6 +16,22 @@
           "field": "IMDB Rating",
           "bandwidth": 0.3,
           "as": ["value", "density"]
+        },
+        {
+          "type": "impute",
+          "field": "density",
+          "groupby": [],
+          "key": "value",
+          "method": "value",
+          "value": 0
+        },
+        {
+          "type": "stack",
+          "groupby": ["value"],
+          "field": "density",
+          "sort": {"field": [], "order": []},
+          "as": ["density_start", "density_end"],
+          "offset": "zero"
         }
       ]
     }
@@ -35,8 +51,8 @@
             "signal": "\"IMDB Rating: \" + (format(datum[\"value\"], \"\")) + \"; density: \" + (format(datum[\"density\"], \"\"))"
           },
           "x": {"scale": "x", "field": "value"},
-          "y": {"scale": "y", "field": "density"},
-          "y2": {"scale": "y", "value": 0},
+          "y": {"scale": "y", "field": "density_end"},
+          "y2": {"scale": "y", "field": "density_start"},
           "defined": {
             "signal": "isValid(datum[\"value\"]) && isFinite(+datum[\"value\"]) && isValid(datum[\"density\"]) && isFinite(+datum[\"density\"])"
           }
@@ -56,7 +72,10 @@
     {
       "name": "y",
       "type": "linear",
-      "domain": {"data": "source_0", "field": "density"},
+      "domain": {
+        "data": "source_0",
+        "fields": ["density_start", "density_end"]
+      },
       "range": [{"signal": "height"}, 0],
       "nice": true,
       "zero": true

examples/compiled/area_horizon.vg.json

@@ -42,7 +42,47 @@
     {
       "name": "data_1",
       "source": "data_0",
-      "transform": [{"type": "formula", "expr": "datum.y - 50", "as": "ny"}]
+      "transform": [
+        {
+          "type": "impute",
+          "field": "y",
+          "groupby": [],
+          "key": "x",
+          "method": "value",
+          "value": 0
+        },
+        {
+          "type": "stack",
+          "groupby": ["x"],
+          "field": "y",
+          "sort": {"field": [], "order": []},
+          "as": ["y_start", "y_end"],
+          "offset": "zero"
+        }
+      ]
+    },
+    {
+      "name": "data_2",
+      "source": "data_0",
+      "transform": [
+        {"type": "formula", "expr": "datum.y - 50", "as": "ny"},
+        {
+          "type": "impute",
+          "field": "ny",
+          "groupby": [],
+          "key": "x",
+          "method": "value",
+          "value": 0
+        },
+        {
+          "type": "stack",
+          "groupby": ["x"],
+          "field": "ny",
+          "sort": {"field": [], "order": []},
+          "as": ["ny_start", "ny_end"],
+          "offset": "zero"
+        }
+      ]
     }
   ],
   "marks": [
@@ -52,7 +92,7 @@
       "clip": true,
       "style": ["area"],
       "sort": {"field": "datum[\"x\"]"},
-      "from": {"data": "data_0"},
+      "from": {"data": "data_1"},
       "encode": {
         "update": {
           "opacity": {"value": 0.6},
@@ -62,8 +102,8 @@
             "signal": "\"x: \" + (format(datum[\"x\"], \"\")) + \"; y: \" + (format(datum[\"y\"], \"\"))"
           },
           "x": {"scale": "x", "field": "x"},
-          "y": {"scale": "y", "field": "y"},
-          "y2": {"scale": "y", "value": 0},
+          "y": {"scale": "y", "field": "y_end"},
+          "y2": {"scale": "y", "field": "y_start"},
           "defined": {
             "signal": "isValid(datum[\"x\"]) && isFinite(+datum[\"x\"]) && isValid(datum[\"y\"]) && isFinite(+datum[\"y\"])"
           }
@@ -76,7 +116,7 @@
       "clip": true,
       "style": ["area"],
       "sort": {"field": "datum[\"x\"]"},
-      "from": {"data": "data_1"},
+      "from": {"data": "data_2"},
       "encode": {
         "update": {
           "orient": {"value": "vertical"},
@@ -86,8 +126,8 @@
             "signal": "\"x: \" + (format(datum[\"x\"], \"\")) + \"; ny: \" + (format(datum[\"ny\"], \"\"))"
           },
           "x": {"scale": "x", "field": "x"},
-          "y": {"scale": "y", "field": "ny"},
-          "y2": {"scale": "y", "value": 0},
+          "y": {"scale": "y", "field": "ny_end"},
+          "y2": {"scale": "y", "field": "ny_start"},
           "defined": {
             "signal": "isValid(datum[\"x\"]) && isFinite(+datum[\"x\"]) && isValid(datum[\"ny\"]) && isFinite(+datum[\"ny\"])"
           }
@@ -101,8 +141,8 @@
       "type": "linear",
       "domain": {
         "fields": [
-          {"data": "data_0", "field": "x"},
-          {"data": "data_1", "field": "x"}
+          {"data": "data_1", "field": "x"},
+          {"data": "data_2", "field": "x"}
         ]
       },
       "range": [0, {"signal": "width"}],

examples/compiled/area_params.vg.json

@@ -21,7 +21,23 @@
       "name": "data_0",
       "source": "source_0",
       "transform": [
-        {"type": "formula", "expr": "toNumber(datum[\"u\"])", "as": "u"}
+        {"type": "formula", "expr": "toNumber(datum[\"u\"])", "as": "u"},
+        {
+          "type": "impute",
+          "field": "v",
+          "groupby": [],
+          "key": "u",
+          "method": "value",
+          "value": 0
+        },
+        {
+          "type": "stack",
+          "groupby": ["u"],
+          "field": "v",
+          "sort": {"field": [], "order": []},
+          "as": ["v_start", "v_end"],
+          "offset": "zero"
+        }
       ]
     }
   ],
@@ -67,8 +83,8 @@
             "signal": "\"u: \" + (format(datum[\"u\"], \"\")) + \"; v: \" + (format(datum[\"v\"], \"\"))"
           },
           "x": {"scale": "x", "field": "u"},
-          "y": {"scale": "y", "field": "v"},
-          "y2": {"scale": "y", "value": 0},
+          "y": {"scale": "y", "field": "v_end"},
+          "y2": {"scale": "y", "field": "v_start"},
           "defined": {
             "signal": "isValid(datum[\"u\"]) && isFinite(+datum[\"u\"]) && isValid(datum[\"v\"]) && isFinite(+datum[\"v\"])"
           }
@@ -88,7 +104,7 @@
     {
       "name": "y",
       "type": "linear",
-      "domain": {"data": "data_0", "field": "v"},
+      "domain": {"data": "data_0", "fields": ["v_start", "v_end"]},
       "range": [{"signal": "height"}, 0],
       "nice": true,
       "zero": true