handle empty markdown for pre-measured

d2graph/d2graph.go

@@ -1164,6 +1164,10 @@ func getMarkdownDimensions(mtexts []*d2target.MText, ruler *textmeasure.Ruler, t
 		return d2target.NewTextDimensions(width, height), nil
 	}
 
+	if strings.TrimSpace(t.Text) == "" {
+		return d2target.NewTextDimensions(1, 1), nil
+	}
+
 	return nil, fmt.Errorf("text not pre-measured and no ruler provided")
 }
 

e2etests/measured_test.go

@@ -26,6 +26,14 @@ func testMeasured(t *testing.T) {
 			name:   "empty-sql_table",
 			mtexts: []*d2target.MText{},
 			script: `a: "" { shape: sql_table }
+`,
+		},
+		{
+			name:   "empty-markdown",
+			mtexts: []*d2target.MText{},
+			script: `a: |md
+` + " " + `
+|
 `,
 		},
 	}

e2etests/testdata/measured/empty-markdown/dagre/board.exp.json

@@ -0,0 +1,88 @@
+{
+  "name": "",
+  "isFolderOnly": false,
+  "fontFamily": "SourceSansPro",
+  "shapes": [
+    {
+      "id": "a",
+      "type": "text",
+      "pos": {
+        "x": 0,
+        "y": 0
+      },
+      "width": 1,
+      "height": 1,
+      "opacity": 1,
+      "strokeDash": 0,
+      "strokeWidth": 2,
+      "borderRadius": 0,
+      "fill": "transparent",
+      "stroke": "N1",
+      "shadow": false,
+      "3d": false,
+      "multiple": false,
+      "double-border": false,
+      "tooltip": "",
+      "link": "",
+      "icon": null,
+      "iconPosition": "",
+      "blend": false,
+      "fields": null,
+      "methods": null,
+      "columns": null,
+      "label": " ",
+      "fontSize": 16,
+      "fontFamily": "DEFAULT",
+      "language": "markdown",
+      "color": "N1",
+      "italic": false,
+      "bold": false,
+      "underline": false,
+      "labelWidth": 1,
+      "labelHeight": 1,
+      "zIndex": 0,
+      "level": 1
+    }
+  ],
+  "connections": [],
+  "root": {
+    "id": "",
+    "type": "",
+    "pos": {
+      "x": 0,
+      "y": 0
+    },
+    "width": 0,
+    "height": 0,
+    "opacity": 0,
+    "strokeDash": 0,
+    "strokeWidth": 0,
+    "borderRadius": 0,
+    "fill": "N7",
+    "stroke": "",
+    "shadow": false,
+    "3d": false,
+    "multiple": false,
+    "double-border": false,
+    "tooltip": "",
+    "link": "",
+    "icon": null,
+    "iconPosition": "",
+    "blend": false,
+    "fields": null,
+    "methods": null,
+    "columns": null,
+    "label": "",
+    "fontSize": 0,
+    "fontFamily": "",
+    "language": "",
+    "color": "",
+    "italic": false,
+    "bold": false,
+    "underline": false,
+    "labelWidth": 0,
+    "labelHeight": 0,
+    "zIndex": 0,
+    "level": 0
+  }
+}