@pdfme/pdf-lib
Version:
Create and modify PDF files with JavaScript
94 lines • 4.49 kB
JavaScript
import PDFHeader from '../document/PDFHeader';
import PDFTrailer from '../document/PDFTrailer';
import PDFInvalidObject from '../objects/PDFInvalidObject';
import PDFName from '../objects/PDFName';
import PDFNumber from '../objects/PDFNumber';
import PDFRef from '../objects/PDFRef';
import PDFStream from '../objects/PDFStream';
import PDFCrossRefStream from '../structures/PDFCrossRefStream';
import PDFObjectStream from '../structures/PDFObjectStream';
import PDFWriter from './PDFWriter';
import { last, waitForTick } from '../../utils';
class PDFStreamWriter extends PDFWriter {
constructor(context, objectsPerTick, encodeStreams, objectsPerStream) {
super(context, objectsPerTick);
Object.defineProperty(this, "encodeStreams", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
Object.defineProperty(this, "objectsPerStream", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
this.encodeStreams = encodeStreams;
this.objectsPerStream = objectsPerStream;
}
async computeBufferSize() {
let objectNumber = this.context.largestObjectNumber + 1;
const header = PDFHeader.forVersion(1, 7);
let size = header.sizeInBytes() + 2;
const xrefStream = PDFCrossRefStream.create(this.createTrailerDict(), this.encodeStreams);
const uncompressedObjects = [];
const compressedObjects = [];
const objectStreamRefs = [];
const indirectObjects = this.context.enumerateIndirectObjects();
for (let idx = 0, len = indirectObjects.length; idx < len; idx++) {
const indirectObject = indirectObjects[idx];
const [ref, object] = indirectObject;
const shouldNotCompress = ref === this.context.trailerInfo.Encrypt ||
object instanceof PDFStream ||
object instanceof PDFInvalidObject ||
ref.generationNumber !== 0;
if (shouldNotCompress) {
uncompressedObjects.push(indirectObject);
xrefStream.addUncompressedEntry(ref, size);
size += this.computeIndirectObjectSize(indirectObject);
if (this.shouldWaitForTick(1))
await waitForTick();
}
else {
let chunk = last(compressedObjects);
let objectStreamRef = last(objectStreamRefs);
if (!chunk || chunk.length % this.objectsPerStream === 0) {
chunk = [];
compressedObjects.push(chunk);
objectStreamRef = PDFRef.of(objectNumber++);
objectStreamRefs.push(objectStreamRef);
}
xrefStream.addCompressedEntry(ref, objectStreamRef, chunk.length);
chunk.push(indirectObject);
}
}
for (let idx = 0, len = compressedObjects.length; idx < len; idx++) {
const chunk = compressedObjects[idx];
const ref = objectStreamRefs[idx];
const objectStream = PDFObjectStream.withContextAndObjects(this.context, chunk, this.encodeStreams);
xrefStream.addUncompressedEntry(ref, size);
size += this.computeIndirectObjectSize([ref, objectStream]);
uncompressedObjects.push([ref, objectStream]);
if (this.shouldWaitForTick(chunk.length))
await waitForTick();
}
const xrefStreamRef = PDFRef.of(objectNumber++);
xrefStream.dict.set(PDFName.of('Size'), PDFNumber.of(objectNumber));
xrefStream.addUncompressedEntry(xrefStreamRef, size);
const xrefOffset = size;
size += this.computeIndirectObjectSize([xrefStreamRef, xrefStream]);
uncompressedObjects.push([xrefStreamRef, xrefStream]);
const trailer = PDFTrailer.forLastCrossRefSectionOffset(xrefOffset);
size += trailer.sizeInBytes();
return { size, header, indirectObjects: uncompressedObjects, trailer };
}
}
Object.defineProperty(PDFStreamWriter, "forContext", {
enumerable: true,
configurable: true,
writable: true,
value: (context, objectsPerTick, encodeStreams = true, objectsPerStream = 50) => new PDFStreamWriter(context, objectsPerTick, encodeStreams, objectsPerStream)
});
export default PDFStreamWriter;
//# sourceMappingURL=PDFStreamWriter.js.map