parallax/jsPDF · error · Error

Invalid code/color length, must be power of 2 and 2 .. 256.

Error message

Invalid code/color length, must be power of 2 and 2 .. 256.

What it means

Thrown by GifWriter's check_palette_and_num_colors when a palette has fewer than 2 entries, more than 256 entries, or a count that is not a power of two. GIF color tables must be a power-of-two size between 2 and 256 because the size is encoded as a log2 field in the descriptor.

Source

Thrown at src/libs/omggif.js:47

"use strict";

import { console } from "./console.js";

function GifWriter(buf, width, height, gopts) {
  var p = 0;

  var gopts = gopts === undefined ? {} : gopts;
  var loop_count = gopts.loop === undefined ? null : gopts.loop;
  var global_palette = gopts.palette === undefined ? null : gopts.palette;

  if (width <= 0 || height <= 0 || width > 65535 || height > 65535)
    throw new Error("Width/Height invalid.");

  function check_palette_and_num_colors(palette) {
    var num_colors = palette.length;
    if (num_colors < 2 || num_colors > 256 || num_colors & (num_colors - 1)) {
      throw new Error(
        "Invalid code/color length, must be power of 2 and 2 .. 256."
      );
    }
    return num_colors;
  }

  // - Header.
  buf[p++] = 0x47;
  buf[p++] = 0x49;
  buf[p++] = 0x46; // GIF
  buf[p++] = 0x38;
  buf[p++] = 0x39;
  buf[p++] = 0x61; // 89a

  // Handling of Global Color Table (palette) and background index.
  var gp_num_colors_pow2 = 0;
  var background = 0;
  if (global_palette !== null) {

View on GitHub (pinned to a3930ce03a)

Solutions

1. Pad the palette to the next power of two between 2 and 256 (e.g. duplicate the last color).
2. Use a quantizer (median-cut, neuquant) that outputs exactly 2^n colors.
3. Validate palette.length is a power of two in range before calling GifWriter.

Example fix

// before
var gw = new GifWriter(buf, w, h, { palette: uniqueColors }); // length 7
// after
function padPalette(p) {
  var n = 2; while (n < p.length) n *= 2; if (n > 256) n = 256;
  while (p.length < n) p.push(p[p.length - 1] || 0);
  return p;
}
var gw = new GifWriter(buf, w, h, { palette: padPalette(uniqueColors.slice()) });

function validPalette(p){ var n = p.length; return n >= 2 && n <= 256 && (n & (n-1)) === 0; }
if (validPalette(palette)) new GifWriter(buf, w, h, { palette: palette });

function isPowerOfTwoPalette(p){ return Array.isArray(p) && p.length >= 2 && p.length <= 256 && (p.length & (p.length-1)) === 0; }

try { new GifWriter(buf, w, h, { palette: pal }); } catch (e) { if (/Invalid code\/color length/.test(e.message)) { /* pad palette */ } else throw e; }

When it happens

Trigger: Passing gopts.palette with length 1, 3, 5, 100, 257, etc. Passing an empty array. Passing a palette with duplicate-trimmed or dynamically-built entries that broke the power-of-two invariant.

Common situations: Building a palette by unique-color extraction that yields an arbitrary count; truncating a 256-color palette to an arbitrary subset; using a 3-color logo palette directly.

Related errors

• Background index out of range.
• Background index explicitly passed as 0.
• Must supply either a local or global palette.
• Transparent color index.
• Width/Height invalid.

AI-assisted analysis of parallax/jsPDF@a3930ce03a (2026-08-13). Data as JSON: /api/errors/34571dc035aac503. Report an issue: GitHub.