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/// <reference lib="webworker" />
import PDFDocument from "pdfkit/lib/document";
import SVGtoPDF from "svg-to-pdfkit";
type ImgType = "svg" | "png";
type DataResultType = "dataUrl" | "text";
const readData = (
data: Blob | Buffer,
type: DataResultType
): string | Promise<string> => {
if (!(data instanceof Uint8Array)) {
// blob
return new Promise((resolve, reject) => {
const reader = new FileReader();
reader.onload = (): void => {
const result = reader.result;
resolve(result as string);
};
reader.onerror = reject;
if (type === "dataUrl") {
reader.readAsDataURL(data);
} else {
reader.readAsText(data);
}
});
} else {
// buffer
if (type === "dataUrl") {
return "data:image/png;base64," + data.toString("base64");
} else {
return data.toString("utf-8");
}
}
};
/**
* @platform browser
*/
const fetchBlob = async (imgUrl: string): Promise<Blob> => {
const r = await fetch(imgUrl, {
cache: "no-cache",
});
return r.blob();
};
/**
* @example
* import { PDFWorker } from '../dist/cache/worker'
* const { generatePDF } = PDFWorker()
* const pdfData = await generatePDF(...)
*/
export const generatePDF = async (
imgBlobs: Blob[] | Buffer[],
imgType: ImgType,
width: number,
height: number
): Promise<ArrayBuffer> => {
// @ts-ignore
const pdf = new (PDFDocument as typeof import("pdfkit"))({
// compress: true,
size: [width, height],
autoFirstPage: false,
margin: 0,
layout: "portrait",
});
if (imgType === "png") {
const imgDataUrlList: string[] = await Promise.all(
imgBlobs.map((b) => readData(b, "dataUrl"))
);
imgDataUrlList.forEach((data) => {
pdf.addPage();
pdf.image(data, {
width,
height,
});
});
} else {
// imgType == "svg"
const svgList = await Promise.all(
imgBlobs.map((b) => readData(b, "text"))
);
svgList.forEach((svg) => {
pdf.addPage();
SVGtoPDF(pdf, svg, 0, 0, {
preserveAspectRatio: "none",
});
});
}
// @ts-ignore
const buf: Uint8Array = await pdf.getBuffer();
return buf.buffer;
};
export type PDFWorkerMessage = [string[], ImgType, number, number];
/**
* @platform browser (web worker)
*/
if (typeof onmessage !== "undefined") {
onmessage = async (e): Promise<void> => {
const [imgUrls, imgType, width, height] = e.data as PDFWorkerMessage;
const imgBlobs = await Promise.all(
imgUrls.map((url) => fetchBlob(url))
);
const pdfBuf = await generatePDF(imgBlobs, imgType, width, height);
postMessage(pdfBuf, [pdfBuf]);
};
}
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