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js/pixel-codec.js

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+(function (global) {
+  'use strict';
+
+  const root = global.PixelIslandModules ||= {};
+  const MAX_DIMENSION = 64;
+
+  function clamp(value, min, max) {
+    return Math.max(min, Math.min(max, value));
+  }
+
+  function clampInt(value, min, max, fallback = min) {
+    const n = Math.round(Number(value));
+    return Number.isFinite(n) ? clamp(n, min, max) : fallback;
+  }
+
+  function clampDimension(value, fallback = 8) {
+    return clampInt(value, 1, MAX_DIMENSION, fallback);
+  }
+
+  function fnv1a(value) {
+    let hash = 0x811c9dc5;
+    const text = String(value);
+    for (let i = 0; i < text.length; i++) {
+      hash ^= text.charCodeAt(i);
+      hash = Math.imul(hash, 0x01000193) >>> 0;
+    }
+    return hash.toString(16).padStart(8, '0');
+  }
+
+  function assetWidth(asset) {
+    return clampInt(asset?.width ?? asset?.w ?? asset?.size, 1, MAX_DIMENSION, 16);
+  }
+
+  function assetHeight(asset) {
+    return clampInt(asset?.height ?? asset?.ht ?? asset?.size, 1, MAX_DIMENSION, assetWidth(asset));
+  }
+
+  function assetMaxSize(asset) {
+    return Math.max(assetWidth(asset), assetHeight(asset));
+  }
+
+  function blankPixels(width, height = width) {
+    return Array(Math.max(1, width) * Math.max(1, height)).fill(null);
+  }
+
+  function parseHex(hex) {
+    if (typeof hex !== 'string' || !hex.startsWith('#')) return null;
+    const clean = hex.replace('#', '');
+    const full = clean.length === 3 ? clean.split('').map((c) => c + c).join('') : clean;
+    const value = parseInt(full, 16);
+    if (!Number.isFinite(value)) return null;
+    return { r: (value >> 16) & 255, g: (value >> 8) & 255, b: value & 255 };
+  }
+
+  function nearestPaletteCodeFrom(entries, color, fallback) {
+    if (!Array.isArray(entries) || !entries.length) return fallback || '0';
+    if (!color || typeof color !== 'string') return fallback || entries[0]?.code || '0';
+    if (entries.some((entry) => entry.code === color)) return color;
+    const rgb = parseHex(color);
+    if (!rgb) return fallback || entries[0]?.code || '0';
+    let best = entries[0]?.code || '0';
+    let bestDist = Infinity;
+    for (const entry of entries) {
+      const entryRgb = parseHex(entry.color);
+      if (!entryRgb) continue;
+      const dist = (rgb.r - entryRgb.r) ** 2 + (rgb.g - entryRgb.g) ** 2 + (rgb.b - entryRgb.b) ** 2;
+      if (dist < bestDist) {
+        bestDist = dist;
+        best = entry.code;
+      }
+    }
+    return best;
+  }
+
+  function normalizePixels(pixels, width, height = width, palette = root.Palette?.PALETTE || [], defaultColorCode = root.Palette?.DEFAULT_SELECTED_COLOR_CODE || 'a') {
+    const out = blankPixels(width, height);
+    const paletteByCode = new Map((palette || []).map((entry) => [entry.code, entry.color]));
+    if (typeof pixels === 'string') {
+      for (let i = 0; i < Math.min(out.length, pixels.length); i++) {
+        const ch = pixels[i];
+        out[i] = ch === '.' ? null : (paletteByCode.has(ch) ? ch : nearestPaletteCodeFrom(palette, ch, defaultColorCode));
+      }
+      return out;
+    }
+    if (!Array.isArray(pixels)) return out;
+    for (let i = 0; i < Math.min(out.length, pixels.length); i++) {
+      const value = pixels[i];
+      if (!value) out[i] = null;
+      else if (paletteByCode.has(value)) out[i] = value;
+      else out[i] = nearestPaletteCodeFrom(palette, value, defaultColorCode);
+    }
+    return out;
+  }
+
+  function encodePixels(pixels, width = null, height = null, palette = root.Palette?.PALETTE || [], defaultColorCode = root.Palette?.DEFAULT_SELECTED_COLOR_CODE || 'a') {
+    const w = width || Math.sqrt(pixels?.length || 0) || 8;
+    const h = height || w;
+    return normalizePixels(pixels, w, h, palette, defaultColorCode).map((value) => value || '.').join('');
+  }
+
+  function buildPixelBlob(encodedPixels, width, height = width, palette = root.Palette?.PALETTE || [], defaultColorCode = root.Palette?.DEFAULT_SELECTED_COLOR_CODE || 'a') {
+    const w = clampDimension(width, 16);
+    const h = clampDimension(height, w);
+    const payload = encodePixels(encodedPixels, w, h, palette, defaultColorCode);
+    const codec = 'palette-index-v1';
+    return {
+      id: computePixelBlobId(codec, w, h, payload, palette, defaultColorCode),
+      codec,
+      width: w,
+      height: h,
+      payload
+    };
+  }
+
+  function computePixelBlobId(codec, width, height, payload, palette = root.Palette?.PALETTE || [], defaultColorCode = root.Palette?.DEFAULT_SELECTED_COLOR_CODE || 'a') {
+    const normalizedCodec = codec || 'palette-index-v1';
+    const w = clampDimension(width, 16);
+    const h = clampDimension(height, w);
+    const encoded = encodePixels(payload, w, h, palette, defaultColorCode);
+    return `blob:${fnv1a(['pixel-blob-v1', normalizedCodec, w, h, encoded].join('|'))}`;
+  }
+
+  function ensureAssetBlobId(asset, palette = root.Palette?.PALETTE || [], defaultColorCode = root.Palette?.DEFAULT_SELECTED_COLOR_CODE || 'a') {
+    if (!asset) return asset;
+    const w = assetWidth(asset);
+    const h = assetHeight(asset);
+    const right = normalizePixels(asset.faces?.right || asset.pixels || blankPixels(w, h), w, h, palette, defaultColorCode);
+    const blob = buildPixelBlob(right, w, h, palette, defaultColorCode);
+    return { ...asset, blobId: asset.blobId || asset.bi || blob.id };
+  }
+
+  function colorToHex(value) {
+    if (!value) return 'rgba(0,0,0,0)';
+    return root.Palette?.PALETTE_BY_CODE?.[value] || value;
+  }
+
+  function nearestPaletteCode(color) {
+    return nearestPaletteCodeFrom(root.Palette?.PALETTE || [], color, root.Palette?.DEFAULT_SELECTED_COLOR_CODE || 'a');
+  }
+
+  function nearestBasicPaletteCode(color) {
+    const palette = root.Palette?.PALETTE || [];
+    const count = root.Palette?.BASIC_PALETTE_COUNT || palette.length;
+    return nearestPaletteCodeFrom(palette.slice(0, count), root.Palette?.PALETTE_BY_CODE?.[color] || color, palette[0]?.code || '0');
+  }
+
+  function readableTextColor(hex) {
+    const rgb = parseHex(hex);
+    if (!rgb) return '#243044';
+    const yiq = (rgb.r * 299 + rgb.g * 587 + rgb.b * 114) / 1000;
+    return yiq > 140 ? '#243044' : '#fffdf5';
+  }
+
+  root.PixelCodec = {
+    MAX_DIMENSION,
+    assetHeight,
+    assetMaxSize,
+    assetWidth,
+    blankPixels,
+    buildPixelBlob,
+    clampDimension,
+    clampInt,
+    colorToHex,
+    computePixelBlobId,
+    ensureAssetBlobId,
+    encodePixels,
+    fnv1a,
+    nearestBasicPaletteCode,
+    nearestPaletteCode,
+    nearestPaletteCodeFrom,
+    normalizePixels,
+    parseHex,
+    readableTextColor
+  };
+})(typeof self !== 'undefined' ? self : window);