From 8769f6d8672d8a82762b5c137a32f724ef9df8d7 Mon Sep 17 00:00:00 2001
From: Mike Bostock <mbostock@gmail.com>
Date: Sun, 21 Feb 2021 10:53:18 -0800
Subject: [PATCH] axis.offset

---
 src/axis.js | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/src/axis.js b/src/axis.js
index b0ecb0c..32edf9f 100644
--- a/src/axis.js
+++ b/src/axis.js
@@ -8,19 +8,19 @@ var top = 1,
     epsilon = 1e-6;
 
 function translateX(x) {
-  return "translate(" + (x + 0.5) + ",0)";
+  return "translate(" + x + ",0)";
 }
 
 function translateY(y) {
-  return "translate(0," + (y + 0.5) + ")";
+  return "translate(0," + y + ")";
 }
 
 function number(scale) {
   return d => +scale(d);
 }
 
-function center(scale) {
-  var offset = Math.max(0, scale.bandwidth() - 1) / 2; // Adjust for 0.5px offset.
+function center(scale, offset) {
+  offset = Math.max(0, scale.bandwidth() - offset * 2) / 2;
   if (scale.round()) offset = Math.round(offset);
   return function(d) {
     return +scale(d) + offset;
@@ -38,6 +38,7 @@ function axis(orient, scale) {
       tickSizeInner = 6,
       tickSizeOuter = 6,
       tickPadding = 3,
+      offset = typeof window !== "undefined" && window.devicePixelRatio >= 2 ? 0 : 0.5,
       k = orient === top || orient === left ? -1 : 1,
       x = orient === left || orient === right ? "x" : "y",
       transform = orient === top || orient === bottom ? translateX : translateY;
@@ -47,9 +48,9 @@ function axis(orient, scale) {
         format = tickFormat == null ? (scale.tickFormat ? scale.tickFormat.apply(scale, tickArguments) : identity) : tickFormat,
         spacing = Math.max(tickSizeInner, 0) + tickPadding,
         range = scale.range(),
-        range0 = +range[0] + 0.5,
-        range1 = +range[range.length - 1] + 0.5,
-        position = (scale.bandwidth ? center : number)(scale.copy()),
+        range0 = +range[0] + offset,
+        range1 = +range[range.length - 1] + offset,
+        position = (scale.bandwidth ? center : number)(scale.copy(), offset),
         selection = context.selection ? context.selection() : context,
         path = selection.selectAll(".domain").data([null]),
         tick = selection.selectAll(".tick").data(values, scale).order(),
@@ -81,23 +82,23 @@ function axis(orient, scale) {
 
       tickExit = tickExit.transition(context)
           .attr("opacity", epsilon)
-          .attr("transform", function(d) { return isFinite(d = position(d)) ? transform(d) : this.getAttribute("transform"); });
+          .attr("transform", function(d) { return isFinite(d = position(d)) ? transform(d + offset) : this.getAttribute("transform"); });
 
       tickEnter
           .attr("opacity", epsilon)
-          .attr("transform", function(d) { var p = this.parentNode.__axis; return transform(p && isFinite(p = p(d)) ? p : position(d)); });
+          .attr("transform", function(d) { var p = this.parentNode.__axis; return transform((p && isFinite(p = p(d)) ? p : position(d)) + offset); });
     }
 
     tickExit.remove();
 
     path
         .attr("d", orient === left || orient === right
-            ? (tickSizeOuter ? "M" + k * tickSizeOuter + "," + range0 + "H0.5V" + range1 + "H" + k * tickSizeOuter : "M0.5," + range0 + "V" + range1)
-            : (tickSizeOuter ? "M" + range0 + "," + k * tickSizeOuter + "V0.5H" + range1 + "V" + k * tickSizeOuter : "M" + range0 + ",0.5H" + range1));
+            ? (tickSizeOuter ? "M" + k * tickSizeOuter + "," + range0 + "H" + offset + "V" + range1 + "H" + k * tickSizeOuter : "M" + offset + "," + range0 + "V" + range1)
+            : (tickSizeOuter ? "M" + range0 + "," + k * tickSizeOuter + "V" + offset + "H" + range1 + "V" + k * tickSizeOuter : "M" + range0 + "," + offset + "H" + range1));
 
     tick
         .attr("opacity", 1)
-        .attr("transform", function(d) { return transform(position(d)); });
+        .attr("transform", function(d) { return transform(position(d) + offset); });
 
     line
         .attr(x + "2", k * tickSizeInner);
@@ -152,6 +153,10 @@ function axis(orient, scale) {
     return arguments.length ? (tickPadding = +_, axis) : tickPadding;
   };
 
+  axis.offset = function(_) {
+    return arguments.length ? (offset = +_, axis) : offset;
+  };
+
   return axis;
 }