eBookReaderSwitch/docs/examples/pdf-merge.js

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// 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 = 1; i < scriptArgs.length; ++i) {
srcDoc = new PDFDocument(scriptArgs[i])
copyAllPages(dstDoc, srcDoc)
}
dstDoc.save(scriptArgs[0], "compress")
}
if (scriptArgs.length < 2)
print("usage: mutool run pdf-merge.js output.pdf input1.pdf input2.pdf ...")
else
pdfmerge()