PngParser: Add unit test for PLTE chunk

Author: codedread

image/parsers/png.js

@@ -14,6 +14,7 @@ import { ByteStream } from '../../io/bytestream.js';
 // https://en.wikipedia.org/wiki/PNG#File_format
 // https://www.w3.org/TR/2003/REC-PNG-20031110
 
+let DEBUG = false;
 const SIG = new Uint8Array([0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]);
 
 /** @enum {string} */
@@ -220,8 +221,9 @@ export class PngParser extends EventTarget {
             });
           }
 
+          /** @type {PngPalette} */
           const palette = {
-            paletteEntries,
+            entries: paletteEntries,
           };
 
           this.dispatchEvent(new PngPaletteEvent(palette));
@@ -240,7 +242,7 @@ export class PngParser extends EventTarget {
           break;
 
         default:
-          console.log(`Found an unhandled chunk: ${chunk.chunkType}`);
+          if (DEBUG) console.log(`Found an unhandled chunk: ${chunk.chunkType}`);
           break;
       }
     } while (chunk.chunkType !== 'IEND');
@@ -295,4 +297,4 @@ async function main() {
   }
 }
 
-main();
+// main();

tests/image-parsers-png.spec.js

@@ -2,10 +2,10 @@ import * as fs from 'node:fs';
 import 'mocha';
 import { expect } from 'chai';
 import { PngColorType, PngInterlaceMethod, PngParser } from '../image/parsers/png.js';
-import { fail } from 'node:assert';
 
 /** @typedef {import('../image/parsers/png.js').PngImageHeader} PngImageHeader */
 /** @typedef {import('../image/parsers/png.js').PngImageData} PngImageData */
+/** @typedef {import('../image/parsers/png.js').PngPalette} PngPalette */
 
 function getPngParser(fileName) {
   const nodeBuf = fs.readFileSync(fileName);
@@ -47,6 +47,19 @@ describe('bitjs.image.parsers.PngParser', () => {
     });
   });
 
+  it('extracts PLTE', async () => {
+    /** @type {PngPalette} */
+    let palette;
+    await getPngParser('tests/image-testfiles/tbbn3p08.png')
+        .onPalette(evt => palette = evt.palette)
+        .start();
+    expect(palette.entries.length).equals(246);
+    const entry = palette.entries[1];
+    expect(entry.red).equals(128);
+    expect(entry.green).equals(86);
+    expect(entry.blue).equals(86);
+  });
+
   it('extracts IDAT', async () => {
     /** @type {PngImageData} */
     let data;