mozilla/pdf.js · error · FormatError

WhitePoint missing - required for color space Lab

Error message

WhitePoint missing - required for color space Lab

What it means

Thrown by the LabCS constructor when the /WhitePoint array is missing or falsy for a /Lab color space. WhitePoint is mandatory for Lab calibration per the PDF spec; pdf.js refuses to default it because Lab color is meaningless without a reference white.

Source

Thrown at src/core/colorspace.js:1207

    }
  }

  getOutputLength(inputLength, alpha01) {
    return ((inputLength * (3 + alpha01)) / 3) | 0;
  }
}

/**
 * LabCS: Based on "PDF Reference, Sixth Ed", p.250
 *
 * The default color is `new Float32Array([0, 0, 0])`.
 */
class LabCS extends ColorSpace {
  constructor(whitePoint, blackPoint, range) {
    super("Lab", 3);

    if (!whitePoint) {
      throw new FormatError(
        "WhitePoint missing - required for color space Lab"
      );
    }
    // Translate args to spec variables
    [this.XW, this.YW, this.ZW] = whitePoint;
    [this.amin, this.amax, this.bmin, this.bmax] = range || [
      -100, 100, -100, 100,
    ];

    // These are here just for completeness - the spec doesn't offer any
    // formulas that use BlackPoint in Lab
    [this.XB, this.YB, this.ZB] = blackPoint || [0, 0, 0];

    // Validate vars as per spec
    if (this.XW < 0 || this.ZW < 0 || this.YW !== 1) {
      throw new FormatError(
        "Invalid WhitePoint components, no fallback available"
      );

View on GitHub (pinned to 5903d58d58)

Solutions

1. Repair the PDF to include a valid /WhitePoint array (Y normalized to 1).
2. Update pdf.js.

function hasWhitePoint(csDict) {
  const wp = csDict.get('WhitePoint');
  return Array.isArray(wp) && wp.length === 3;
}

try {
  cs = ColorSpace.parse(res, xref, cs, pdfFunctionFactory);
} catch (e) {
  if (e instanceof FormatError && /WhitePoint missing.*Lab/.test(e.message)) {
    console.warn('Lab missing WhitePoint, falling back', e);
    cs = null;
  } else throw e;
}

When it happens

Trigger: Constructing LabCS with whitePoint = null/undefined/[], or parsing a PDF /Lab dictionary that lacks /WhitePoint.

Common situations: Corrupt PDF with an incomplete Lab dictionary; a faulty PDF generator that omitted the reference white.

Related errors

• WhitePoint missing - required for color space CalGray
• WhitePoint missing - required for color space CalRGB
• Invalid WhitePoint components, no fallback available
• IndexedCS - unrecognized lookup table: ${lookup}
• Invalid WhitePoint components for ${this.name}, no fallback

AI-assisted analysis of mozilla/pdf.js@5903d58d58 (2026-08-13). Data as JSON: /api/errors/a1b817edcc4b525b. Report an issue: GitHub.