rx and ry are implied auto

Author: mbostock

src/marks/rect.js

@@ -1,8 +1,8 @@
 import {ascending} from "d3";
 import {create} from "d3";
 import {filter} from "../defined.js";
-import {Mark, number, maybeColor, maybeZero, title, string} from "../mark.js";
-import {Style, applyDirectStyles, applyIndirectStyles, applyTransform} from "../style.js";
+import {Mark, number, maybeColor, maybeZero, title} from "../mark.js";
+import {Style, applyDirectStyles, applyIndirectStyles, applyTransform, impliedString} from "../style.js";
 
 export class Rect extends Mark {
   constructor(
@@ -47,8 +47,8 @@ export class Rect extends Mark {
     this.insetRight = number(insetRight);
     this.insetBottom = number(insetBottom);
     this.insetLeft = number(insetLeft);
-    this.rx = string(rx); // number of percentage
-    this.ry = string(ry);
+    this.rx = impliedString(rx, "auto"); // number of percentage
+    this.ry = impliedString(ry, "auto");
   }
   render(
     I,