fix point scales

Author: mbostock

src/marks/pointer.js

@@ -48,26 +48,38 @@ export class Pointer extends Mark {
         .call(applyDirectStyles, this)
       .node();
 
+    // Note that point scales also expose a bandwidth function, but that always
+    // returns zero. SVG will not render a stroked rect with zero width or
+    // height, so we’ll render these as lines instead.
+    const bx = x?.bandwidth?.();
+    const by = y?.bandwidth?.();
+
+    // The visual representation of the logical selection depends on which
+    // channels are available (x, y, or both) and whether the corresponding
+    // scales are band scales.
+    const createElement = X && Y
+      ? (bx && by ? i => element("rect", {x: X[i], y: Y[i], width: bx, height: by})
+        : bx ? i => element("line", {x1: X[i], x2: X[i] + bx, y1: Y[i], y2: Y[i]})
+        : by ? i => element("line", {x1: X[i], x2: X[i], y1: Y[i], y2: Y[i] + by})
+        : i => element("circle", {cx: X[i], cy: Y[i], r: 4}))
+      : X ? (bx ? i => element("rect", {x: X[i], y: marginTop, width: bx, height: height - marginBottom - marginTop})
+        : i => element("line", {x1: X[i], x2: X[i], y1: marginTop, y2: height - marginBottom}))
+      : (by ? i => element("rect", {x: marginLeft, y: Y[i], width: width - marginRight - marginLeft, height: by})
+        : i => element("line", {y1: Y[i], y2: Y[i], x1: marginLeft, x2: width - marginRight}));
+
     // Renders the given logical selection S, a subset of index. Applies
-    // copy-on-write to the array of circles C. Returns true if the selection
+    // copy-on-write to the array of elements C. Returns true if the selection
     // changed, and false otherwise.
     function render(S) {
       const SC = [];
       let changed = false;
 
-      // Enter (append) the newly-selected elements. The order of the circles is
+      // Enter (append) the newly-selected elements. The order of elements is
       // arbitrary, with the most recently selected datum on top.
       S.forEach(i => {
         let c = C[i];
         if (!c) {
-          c = X && Y ? (x.bandwidth && y.bandwidth ? element("rect", {x: X[i], y: Y[i], width: x.bandwidth(), height: y.bandwidth()})
-              : x.bandwidth ? element("line", {x1: X[i], x2: X[i] + x.bandwidth(), y1: Y[i], y2: Y[i]})
-              : y.bandwidth ? element("line", {x1: X[i], x2: X[i], y1: Y[i], y2: Y[i] + y.bandwidth()})
-              : element("circle", {cx: X[i], cy: Y[i], r: 4}))
-            : X ? (x.bandwidth ? element("rect", {x: X[i], y: marginTop, width: x.bandwidth(), height: height - marginBottom - marginTop})
-              : element("line", {x1: X[i], x2: X[i], y1: marginTop, y2: height - marginBottom}))
-            : (y.bandwidth ? element("rect", {x: marginLeft, y: Y[i], width: width - marginRight - marginLeft, height: y.bandwidth()})
-              : element("line", {y1: Y[i], y2: Y[i], x1: marginLeft, x2: width - marginRight}));
+          c = createElement(i);
           parent.appendChild(c);
           changed = true;
         }