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spacing < MIN_SPACING
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kurkle committed Jan 4, 2019
1 parent ef2ed17 commit 9b69423
Showing 1 changed file with 18 additions and 12 deletions.
30 changes: 18 additions & 12 deletions src/scales/scale.linearbase.js
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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 {
Expand All @@ -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;
}
}
Expand All @@ -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;
}
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