From 9b69423cd3bcfeca32a5e443aa9d1f50a51a166b Mon Sep 17 00:00:00 2001
From: Jukka Kurkela <jukka.kurkela@gmail.com>
Date: Fri, 4 Jan 2019 15:17:33 +0200
Subject: [PATCH] spacing < MIN_SPACING

---
 src/scales/scale.linearbase.js | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/src/scales/scale.linearbase.js b/src/scales/scale.linearbase.js
index f86fbc9ba81..1ad3c9a75bb 100644
--- a/src/scales/scale.linearbase.js
+++ b/src/scales/scale.linearbase.js
@@ -15,8 +15,8 @@ function generateTicks(generationOptions, dataRange) {
 	// "nice number" algorithm. See https://stackoverflow.com/questions/8506881/nice-label-algorithm-for-charts-with-minimum-ticks
 	// for details.
 
-	var MAX_PRECISION = 1e14;
-	var MIN_SPACING = 2e-15;
+	// Minimum spacing between ticks
+	var MIN_SPACING = 1e-14;
 	var stepSize = generationOptions.stepSize;
 	var unit = stepSize || 1;
 	var maxNumSpaces = generationOptions.maxTicks - 1;
@@ -25,21 +25,26 @@ function generateTicks(generationOptions, dataRange) {
 	var precision = generationOptions.precision;
 	var spacing, factor, niceMin, niceMax, numSpaces;
 
-	// sanitize dataRangee to MAX_PRECISION
-	var rmin = Math.floor(dataRange.min * MAX_PRECISION) / MAX_PRECISION;
-	var rmax = Math.ceil(dataRange.max * MAX_PRECISION) / MAX_PRECISION;
+	var rmin = dataRange.min;
+	var rmax = dataRange.max;
+	var isNullOrUndef = helpers.isNullOrUndef;
 
 	// spacing is set to a nice number of the dataRange divided by maxNumSpaces.
 	// stepSize is used as a minimum unit if it is specified.
-	// use MIN_SPACING as lower bound to avoid uneven steps with tiny numbers
-	spacing = Math.max(helpers.niceNum((rmax - rmin) / maxNumSpaces / unit) * unit, MIN_SPACING);
+	spacing = helpers.niceNum((rmax - rmin) / maxNumSpaces / unit) * unit;
+
+	// In case of really small numbers and min / max are undefined, default to rmin / rmax
+	if (spacing < MIN_SPACING && isNullOrUndef(min) && isNullOrUndef(max)) {
+		return [rmin, rmax];
+	}
+
 	numSpaces = Math.ceil(rmax / spacing) - Math.floor(rmin / spacing);
 	if (numSpaces > maxNumSpaces) {
 		// If the calculated num of spaces exceeds maxNumSpaces, recalculate it
 		spacing = helpers.niceNum(numSpaces * spacing / maxNumSpaces / unit) * unit;
 	}
 
-	if (stepSize || helpers.isNullOrUndef(precision)) {
+	if (stepSize || isNullOrUndef(precision)) {
 		// If a precision is not specified, calculate factor based on spacing
 		factor = Math.pow(10, helpers.decimalPlaces(spacing));
 	} else {
@@ -54,10 +59,10 @@ function generateTicks(generationOptions, dataRange) {
 	// If min, max and stepSize is set and they make an evenly spaced scale use it.
 	if (stepSize) {
 		// If very close to our whole number, use it.
-		if (!helpers.isNullOrUndef(min) && helpers.almostWhole(min / spacing, spacing / 1000)) {
+		if (!isNullOrUndef(min) && helpers.almostWhole(min / spacing, spacing / 1000)) {
 			niceMin = min;
 		}
-		if (!helpers.isNullOrUndef(max) && helpers.almostWhole(max / spacing, spacing / 1000)) {
+		if (!isNullOrUndef(max) && helpers.almostWhole(max / spacing, spacing / 1000)) {
 			niceMax = max;
 		}
 	}
@@ -69,13 +74,14 @@ function generateTicks(generationOptions, dataRange) {
 	} else {
 		numSpaces = Math.ceil(numSpaces);
 	}
+
 	niceMin = Math.round(niceMin * factor) / factor;
 	niceMax = Math.round(niceMax * factor) / factor;
-	ticks.push(helpers.isNullOrUndef(min) ? niceMin : min);
+	ticks.push(isNullOrUndef(min) ? niceMin : min);
 	for (var j = 1; j < numSpaces; ++j) {
 		ticks.push(Math.round((niceMin + j * spacing) * factor) / factor);
 	}
-	ticks.push(helpers.isNullOrUndef(max) ? niceMax : max);
+	ticks.push(isNullOrUndef(max) ? niceMax : max);
 
 	return ticks;
 }