fix(pdfkit): deflate decoded PNG pixels as Buffer

.changeset/fix-png-deflate-buffer.md

@@ -0,0 +1,5 @@
+---
+"@react-pdf/pdfkit": patch
+---
+
+fix(pdfkit): deflate decoded PNG pixels as Buffer

packages/pdfkit/src/image/png.js

@@ -171,7 +171,8 @@ class PNGImage {
 
   decodeData() {
     this.image.decodePixels((pixels) => {
-      this.imgData = zlib.deflateSync(pixels);
+      const data = Buffer.isBuffer(pixels) ? pixels : Buffer.from(pixels);
+      this.imgData = zlib.deflateSync(data);
       this.finalize();
     });
   }

packages/pdfkit/tests/image/png.test.ts

@@ -0,0 +1,53 @@
+import fs from 'fs';
+import { describe, expect, it, vi } from 'vitest';
+
+vi.mock('zlib', async () => {
+  const zlib = await import('browserify-zlib');
+  return { ...zlib, default: zlib.default };
+});
+
+const { default: PNGImage } = await import('../../src/image/png.js');
+
+const fixtureUrl = new URL('../assets/interlaced-rgb.png', import.meta.url);
+
+const createDocument = () => {
+  const refs: { data: Record<string, unknown>; value?: unknown }[] = [];
+
+  return {
+    refs,
+    ref(data = {}) {
+      const ref = {
+        data,
+        value: undefined,
+        end(value?: unknown) {
+          this.value = value;
+        },
+      };
+
+      refs.push(ref);
+      return ref;
+    },
+  };
+};
+
+describe('PNG images', () => {
+  it('deflates decoded interlaced RGB pixels as a Buffer in browser zlib builds', () => {
+    // 8x8 RGB PNG generated with Adam7 interlace, filter type 0 rows, no alpha, and no tRNS chunk.
+    const image = new PNGImage(fs.readFileSync(fixtureUrl), 'interlaced-rgb');
+
+    expect(image.image.interlaceMethod).toBe(1);
+    expect(image.image.hasAlphaChannel).toBe(false);
+    expect(image.image.transparency).toEqual({});
+
+    const decodedPixels = new Uint8Array(
+      image.width * image.height * image.image.colors,
+    );
+
+    image.image.decodePixels = (callback) => callback(decodedPixels);
+
+    const document = createDocument();
+
+    expect(() => image.embed(document)).not.toThrow();
+    expect(Buffer.isBuffer(document.refs[0].value)).toBe(true);
+  });
+});

vitest.workspace.js

@@ -14,4 +14,5 @@ export default [
   'packages/svg',
   'packages/math',
   'packages/mermaid',
+  'packages/pdfkit',
 ];