From ecd525d78205a8e89f24204a1c7e3f0f4e7412a0 Mon Sep 17 00:00:00 2001
From: Marc Mintel <marc@mintel.me>
Date: Fri, 12 Jun 2026 15:35:19 +0200
Subject: [PATCH] feat(pdf): build stream-hacking pipeline for 5-color pantone
 289 c export

---
 scripts/generate-business-cards.ts |   6 +-
 scripts/inject-pantone.ts          | 106 +++++++++++++++++++++++++++++
 2 files changed, 111 insertions(+), 1 deletion(-)
 create mode 100644 scripts/inject-pantone.ts

diff --git a/scripts/generate-business-cards.ts b/scripts/generate-business-cards.ts
index 0d15f933..135eae1c 100644
--- a/scripts/generate-business-cards.ts
+++ b/scripts/generate-business-cards.ts
@@ -121,7 +121,11 @@ async function generateBusinessCards() {
     try {
       execSync(cmykCommand, { stdio: 'inherit' });
       fs.unlinkSync(tempViaprintoPath);
-      console.log(`✓ CMYK Print File generated: ${finalFileNameCMYK}`);
+      console.log(`[INFO] Injecting PANTONE 289 C Spot Color...`);
+      const injectPantoneCommand = `npx tsx scripts/inject-pantone.ts "${finalPathCMYK}"`;
+      execSync(injectPantoneCommand, { stdio: 'inherit' });
+
+      console.log(`✓ 5-Color Print File generated: ${finalFileNameCMYK}`);
     } catch (e) {
       console.error(`❌ CMYK conversion failed! Is Ghostscript installed?`);
     }
diff --git a/scripts/inject-pantone.ts b/scripts/inject-pantone.ts
new file mode 100644
index 00000000..6f4fb166
--- /dev/null
+++ b/scripts/inject-pantone.ts
@@ -0,0 +1,106 @@
+import { PDFDocument, PDFName, decodePDFRawStream, PDFRawStream } from 'pdf-lib';
+import fs from 'fs';
+import path from 'path';
+
+async function run() {
+  const inputPath = process.argv[2];
+  const outputPath = process.argv[3] || inputPath;
+
+  if (!inputPath || !fs.existsSync(inputPath)) {
+    console.error(`[ERROR] Input file not found: ${inputPath}`);
+    process.exit(1);
+  }
+
+  console.log(`[INFO] Injecting PANTONE 289 C into: ${path.basename(inputPath)}`);
+  const pdfBytes = fs.readFileSync(inputPath);
+  const pdfDoc = await PDFDocument.load(pdfBytes);
+
+  // CMYK tint transform for PANTONE 289 C.
+  // Approximation: 100C, 64M, 0Y, 60K (1.0 0.64 0.0 0.60)
+  // The function maps an input x (0 to 1) to CMYK: x*1.0, x*0.64, x*0.0, x*0.60
+  const tintTransform = pdfDoc.context.stream(
+    '{ dup 1.0 mul exch dup 0.64 mul exch dup 0.0 mul exch 0.60 mul }',
+    {
+      FunctionType: 4,
+      Domain: [0, 1],
+      Range: [0, 1, 0, 1, 0, 1, 0, 1],
+    },
+  );
+
+  // Create the /Separation color space array
+  const pantoneCS = pdfDoc.context.obj([
+    PDFName.of('Separation'),
+    PDFName.of('PANTONE#20289#20C'),
+    PDFName.of('DeviceCMYK'),
+    tintTransform,
+  ]);
+  const csRef = pdfDoc.context.register(pantoneCS);
+
+  const pages = pdfDoc.getPages();
+  for (const page of pages) {
+    let resources = page.node.Resources();
+    if (!resources) {
+      resources = pdfDoc.context.obj({});
+      page.node.set(PDFName.of('Resources'), resources);
+    }
+
+    // Ensure ColorSpace dict exists
+    let colorSpaces = resources.get(PDFName.of('ColorSpace')) as any;
+    if (!colorSpaces) {
+      colorSpaces = pdfDoc.context.obj({});
+      resources.set(PDFName.of('ColorSpace'), colorSpaces);
+    }
+    // Register the PANTONE color space as /CSPantone in the page's resources
+    colorSpaces.set(PDFName.of('CSPantone'), csRef);
+
+    // Read all content streams
+    const contents = page.node.Contents();
+    let streams: any[] = [];
+    if (contents) {
+      const resolvedContents = pdfDoc.context.lookup(contents);
+      if (resolvedContents instanceof PDFRawStream) {
+        streams = [resolvedContents];
+      } else if (resolvedContents.constructor.name === 'PDFArray') {
+        const arr = resolvedContents as any;
+        for (let j = 0; j < arr.size(); j++) {
+          streams.push(pdfDoc.context.lookup(arr.get(j)));
+        }
+      }
+    }
+
+    let newStr = '';
+    for (let i = 0; i < streams.length; i++) {
+      const stream = streams[i];
+      if (stream instanceof PDFRawStream) {
+        const decoded = decodePDFRawStream(stream).decode();
+        const str = Buffer.from(decoded).toString('utf-8');
+        newStr += str + '\n';
+      }
+    }
+
+    // The CMYK values for the KLZ Blue created by Ghostscript from #000a66
+    // is '1 0.98 0.224 0.298'. We use a slightly dynamic regex to catch small precision diffs.
+    const dynamicRegexK = /1 0\.98[0-9]* 0\.224[0-9]* 0\.298[0-9]* k/g;
+    const dynamicRegexStrokeK = /1 0\.98[0-9]* 0\.224[0-9]* 0\.298[0-9]* K/g;
+
+    let modified = false;
+    if (dynamicRegexK.test(newStr) || dynamicRegexStrokeK.test(newStr)) {
+      newStr = newStr.replace(dynamicRegexK, '/CSPantone cs 1 scn');
+      newStr = newStr.replace(dynamicRegexStrokeK, '/CSPantone CS 1 SCN');
+      modified = true;
+    }
+
+    if (modified) {
+      const newStream = pdfDoc.context.flateStream(newStr);
+      const newRef = pdfDoc.context.register(newStream);
+      page.node.set(PDFName.of('Contents'), newRef);
+      console.log(`[INFO] Spot color injected into page ${pages.indexOf(page) + 1}.`);
+    }
+  }
+
+  const finalPdfBytes = await pdfDoc.save();
+  fs.writeFileSync(outputPath, finalPdfBytes);
+  console.log(`[SUCCESS] Saved 5-color PDF to ${outputPath}`);
+}
+
+run().catch(console.error);