Add pdf-dejpx.js example script.

1 files changed, 55 insertions, 0 deletions

diff --git a/docs/examples/pdf-dejpx.js b/docs/examples/pdf-dejpx.js
new file mode 100644
index 00000000..0497337a
--- /dev/null
+++ b/docs/examples/pdf-dejpx.js
@@ -0,0 +1,55 @@
+// Find all JPEG-2000 images and turn them into regular images.
+
+var doc = new PDFDocument(scriptArgs[0]);
+
+function isJPXImage(ref) {
+	if ("Filter" in ref) {
+		var filter = ref.Filter;
+		if (filter == "JPXDecode")
+			return true;
+		if (filter.isArray())
+			for (var i = 0; i < filter.length; ++i)
+				if (filter[i] == "JPXDecode")
+					return true;
+	}
+	return false;
+}
+
+var i, n, ref;
+
+var jpxList = {};
+var smaskList = {};
+
+// Preload and destroy all JPX images.
+n = doc.countObjects();
+for (i=1; i < n; ++i) {
+	ref = doc.newIndirect(i, 0);
+	if (isJPXImage(ref)) {
+		print("Loading JPX image:", i)
+		jpxList[i] = doc.loadImage(ref);
+		if ("SMask" in ref)
+			smaskList[i] = ref.SMask;
+		ref.writeObject(null); // make sure we don't reuse the JPX image resource
+	}
+}
+
+for (i in jpxList) {
+	ref = doc.newIndirect(i, 0);
+	var jpx = jpxList[i];
+	var pix = jpx.toPixmap();
+	var raw = new Image(pix);
+
+	// Create a new image, then copy the data to the old object, then delete it.
+	print("Decompressed image:", i);
+	var img = doc.addImage(raw);
+	if (i in smaskList)
+		img.SMask = smaskList[i];
+	ref.writeObject(img.resolve());
+	ref.writeRawStream(img.readRawStream());
+	doc.deleteObject(img);
+
+	// Invoke the GC to free intermediate pixmaps and images.
+	gc();
+}
+
+doc.save(scriptArgs[1], "compress,garbage=compact");