1 files changed, 67 insertions, 0 deletions
diff --git a/docs/examples/pdf-merge.js b/docs/examples/pdf-merge.js
new file mode 100644
index 00000000..d8cdcfcb
--- /dev/null
+++ b/docs/examples/pdf-merge.js
@@ -0,0 +1,67 @@
+// A re-implementation of "mutool merge" in JavaScript.
+
+function graftObject(dstDoc, srcDoc, srcObj, map) {
+	var srcNum, dstRef, dstObj
+	if (!map)
+		map = []
+	if (srcObj.isIndirect()) {
+		srcNum = srcObj.toIndirect()
+		if (map[srcNum])
+			return map[srcNum]
+		map[srcNum] = dstRef = dstDoc.createObject()
+		dstRef.writeObject(graftObject(dstDoc, srcDoc, srcObj.resolve(), map))
+		if (srcObj.isStream())
+			dstRef.writeRawStream(srcObj.readRawStream())
+		return dstRef
+	}
+	if (srcObj.isArray()) {
+		dstObj = dstDoc.newArray()
+		srcObj.forEach(function (key, val) {
+			dstObj[key] = graftObject(dstDoc, srcDoc, val, map)
+		})
+		return dstObj
+	}
+	if (srcObj.isDictionary()) {
+		dstObj = dstDoc.newDictionary()
+		srcObj.forEach(function (key, val) {
+			dstObj[key] = graftObject(dstDoc, srcDoc, val, map)
+		})
+		return dstObj
+	}
+	return srcObj /* primitive objects are not bound to a document */
+}
+
+function copyPage(dstDoc, srcDoc, pageNumber, map) {
+	var srcPage, dstPage
+	srcPage = srcDoc.findPage(pageNumber)
+	dstPage = dstDoc.newDictionary()
+	dstPage.Type = dstDoc.newName("Page")
+	if (srcPage.MediaBox) dstPage.MediaBox = graftObject(dstDoc, srcDoc, srcPage.MediaBox, map)
+	if (srcPage.Rotate) dstPage.Rotate = graftObject(dstDoc, srcDoc, srcPage.Rotate, map)
+	if (srcPage.Resources) dstPage.Resources = graftObject(dstDoc, srcDoc, srcPage.Resources, map)
+	if (srcPage.Contents) dstPage.Contents = graftObject(dstDoc, srcDoc, srcPage.Contents, map)
+	dstDoc.insertPage(-1, dstDoc.addObject(dstPage))
+}
+
+function copyAllPages(dstDoc, srcDoc) {
+	var k, n = srcDoc.countPages()
+	var srcMap = []
+	for (k = 0; k < n; ++k)
+		copyPage(dstDoc, srcDoc, k, srcMap)
+}
+
+function pdfmerge() {
+	var srcDoc, dstDoc, i
+
+	dstDoc = new PDFDocument()
+	for (i = 2; i < argv.length; ++i) {
+		srcDoc = new PDFDocument(argv[i])
+		copyAllPages(dstDoc, srcDoc)
+	}
+	dstDoc.save(argv[1], "compress")
+}
+
+if (argv.length < 3)
+	print("usage: mutool run pdf-merge.js output.pdf input1.pdf input2.pdf ...")
+else
+	pdfmerge()