mozilla/pdf.js · error · Error

Images with ${image.numComps} color components not supported

Error message

Images with ${image.numComps} color components not supported.

What it means

Thrown when an image has no explicit ColorSpace and is not a JPX/JPEG2000 image, but its number of color components (numComps) is not 1, 3, or 4. PDF.js infers DeviceGray/RGB/CMYK only for those counts; any other count cannot be mapped to a default device space.

Source

Thrown at src/core/image.js:233

        }
      }

      if (!hasColorSpace) {
        if (this.jpxDecoderOptions) {
          colorSpace = Name.get("DeviceRGBA");
        } else {
          switch (image.numComps) {
            case 1:
              colorSpace = Name.get("DeviceGray");
              break;
            case 3:
              colorSpace = Name.get("DeviceRGB");
              break;
            case 4:
              colorSpace = Name.get("DeviceCMYK");
              break;
            default:
              throw new Error(
                `Images with ${image.numComps} color components not supported.`
              );
          }
        }
      } else if (this.jpxDecoderOptions?.smaskInData) {
        // If the jpx image has a color space then it mustn't be used in order
        // to be able to use the color space that comes from the pdf.
        colorSpace = Name.get("DeviceRGBA");
      }

      this.colorSpace = ColorSpaceUtils.parse({
        cs: colorSpace,
        xref,
        resources: isInline ? res : null,
        pdfFunctionFactory,
        globalColorSpaceCache,
        localColorSpaceCache,
      });

View on GitHub (pinned to 5903d58d58)

Solutions

1. When generating PDFs, always attach an explicit /ColorSpace to images whose component count is not 1/3/4.
2. Convert the source image to Gray/RGB/CMYK before embedding.
3. Catch the Error at render time and skip the image.
4. If the image is JPEG2000, ensure jpx decoder options are configured so pdf.js takes the JPX branch.

// For images you author, map component counts to a ColorSpace explicitly:
function defaultColorSpaceForComponents(numComps) {
  switch (numComps) {
    case 1: return 'DeviceGray';
    case 3: return 'DeviceRGB';
    case 4: return 'DeviceCMYK';
    default: return null; // must specify ColorSpace explicitly
  }
}

function isInferableComponentCount(n) {
  return n === 1 || n === 3 || n === 4;
}

try { await page.render({ canvasContext }).promise; }
catch (err) {
  if (/color components not supported/.test(err?.message || '')) {
    console.warn('Image has unsupported component count; skipping.');
  } else throw err;
}

When it happens

Trigger: An image stream with numComps of e.g. 2 or 5, no /ColorSpace, and not handled by jpxDecoderOptions. Reached while rendering such an image's XObject or inline form.

Common situations: Multi-channel or specialized images embedded without a ColorSpace; images whose component count was misreported by a damaged decoder; non-JP2 images that should have declared an Indexed or DeviceN space.

Related errors

• Unable to decode inline image: "${reason}".
• Unsupported number of components: ${numComps}
• Invalid image width: ${width} or height: ${height}
• Bits per component missing in image: ${this.imageMask}
• Unknown mask format.

AI-assisted analysis of mozilla/pdf.js@5903d58d58 (2026-08-13). Data as JSON: /api/errors/4d202ea1f0479f46. Report an issue: GitHub.