pdf-lib 图像不显示

Question

I'm trying to add an image to a pdf using pdf-lib ( https://github.com/Hopding/pdf-lib ). It works fine when I do:

const { PDFDocument, StandardFonts, rgb } = PDFLib;
async function createPdf() {
    const pdfDoc = await PDFDocument.create();
    const page = pdfDoc.addPage();
    const jpgUrl = '/images/logo.jpg';
    const jpgImageBytes = await fetch(jpgUrl).then((res) => res.arrayBuffer());
    const jpgImage = await pdfDoc.embedJpg(jpgImageBytes);
    page.drawImage(jpgImage, {
        x: 7,
        y: 800,
        width: 196,
        height: 30
    });
}
const pdfBytes = await pdfDoc.save();

But when I'm wrapping some of the code in a function, it won't render the image:

const { PDFDocument, StandardFonts, rgb } = PDFLib;
async function createPdf() {
    const pdfDoc = await PDFDocument.create();
    const page = pdfDoc.addPage();
    async function image() {
        const jpgUrl = '/images/logo.jpg';
        const jpgImageBytes = await fetch(jpgUrl).then((res) => res.arrayBuffer());
        const jpgImage = await pdfDoc.embedJpg(jpgImageBytes);
        page.drawImage(jpgImage, {
            x: 7,
            y: 800,
            width: 196,
            height: 30
        });
        console.log('done');
    }
    image();
}
const pdfBytes = await pdfDoc.save();

It does not showing any errors and prints 'done' in the console as expected. Does it has to do with async functions (which I know very little about)?

Answer 1

It was quite simple. I just needed to use 'await' when calling the image() function.

const { PDFDocument, StandardFonts, rgb } = PDFLib;
async function createPdf() {
    const pdfDoc = await PDFDocument.create();
    const page = pdfDoc.addPage();
    async function image() {
        const jpgUrl = '/images/logo.jpg';
        const jpgImageBytes = await fetch(jpgUrl).then((res) => res.arrayBuffer());
        const jpgImage = await pdfDoc.embedJpg(jpgImageBytes);
        page.drawImage(jpgImage, {
            x: 7,
            y: 800,
            width: 196,
            height: 30
        });
        console.log('done');
    }
    await image();
}
const pdfBytes = await pdfDoc.save();