From de485636b46c73372042801c5ba9a1ad4a4d6b66 Mon Sep 17 00:00:00 2001
From: Mike Bostock <mbostock@gmail.com>
Date: Thu, 8 Apr 2021 13:40:29 -0700
Subject: [PATCH] autoround

---
 src/scales.js         |  8 ++++++++
 src/scales/ordinal.js | 20 ++++++++++++--------
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/scales.js b/src/scales.js
index 1e805f0b51..a339508657 100644
--- a/src/scales.js
+++ b/src/scales.js
@@ -35,6 +35,7 @@ function autoScaleRangeX(scale, dimensions) {
     const {width, marginLeft = 0, marginRight = 0} = dimensions;
     scale.scale.range([marginLeft + inset, width - marginRight - inset]);
   }
+  autoScaleRound(scale);
 }
 
 function autoScaleRangeY(scale, dimensions) {
@@ -45,6 +46,13 @@ function autoScaleRangeY(scale, dimensions) {
     if (scale.type === "ordinal") range.reverse();
     scale.scale.range(range);
   }
+  autoScaleRound(scale);
+}
+
+function autoScaleRound(scale) {
+  if (scale.round === undefined && scale.type === "ordinal" && scale.scale.step() >= 5) {
+    scale.scale.round(true);
+  }
 }
 
 function Scale(key, channels = [], options = {}) {
diff --git a/src/scales/ordinal.js b/src/scales/ordinal.js
index f1c9ed6fa2..59012a3de8 100644
--- a/src/scales/ordinal.js
+++ b/src/scales/ordinal.js
@@ -209,14 +209,12 @@ export function ScaleOrdinal(key, channels, {
 export function ScalePoint(key, channels, {
   align = 0.5,
   padding = 0.5,
-  round = true,
   ...options
 }) {
-  return ScaleO(
+  return maybeRound(
     scalePoint()
       .align(align)
-      .padding(padding)
-      .round(round),
+      .padding(padding),
     channels,
     options
   );
@@ -227,20 +225,26 @@ export function ScaleBand(key, channels, {
   padding = 0.1,
   paddingInner = padding,
   paddingOuter = key === "fx" || key === "fy" ? 0 : padding,
-  round = true,
   ...options
 }) {
-  return ScaleO(
+  return maybeRound(
     scaleBand()
       .align(align)
       .paddingInner(paddingInner)
-      .paddingOuter(paddingOuter)
-      .round(round),
+      .paddingOuter(paddingOuter),
     channels,
     options
   );
 }
 
+function maybeRound(scale, channels, options = {}) {
+  const {round} = options;
+  if (round !== undefined) scale.round(round);
+  scale = ScaleO(scale, channels, options);
+  scale.round = round;
+  return scale;
+}
+
 function inferDomain(channels) {
   const domain = new Set();
   for (const {value} of channels) {