PDF to JPG

Page 1 of report-a4-3pages.pdf at scale 2 and quality 80 is a JPEG of 1191 by 1684 pixels, 21.7 KB. The width is 595.28 points times 2, rounded. The height is 841.89 points times 2, rounded. Page 2 of invoice-letter-2pages.pdf at scale 1 and quality 60 is 612 by 792 pixels, 6.5 KB, which is the US Letter size at 72 pixels per inch. Both numbers came from rendering the page, not from guessing a thumbnail size.

pdf.js opens the file in the browser and draws one page onto a canvas. The canvas becomes a JPEG at the quality you typed. pdf-lib is not involved, because the download is an image, not a PDF. The words you see are paint. You cannot drag a sentence out of the JPEG, and a search in a photo viewer will not find them.

Scale is capped from 0.5 to 4 so a 200-page file cannot ask for a poster-sized bitmap by accident. This page still renders one page at a time. A multi-page export would be a zip of JPEGs, and that is a different job from looking at page 2. Quality runs from 1 to 100. 60 is visibly softer than 80 on a page of small type. For a slide with big type, 60 is often enough.

A password-protected PDF stops here with an error. The file is not uploaded in order to ask a server to crack it. Encrypted files stay closed. A broken cross-reference table also stops, and the message names the failure instead of returning a blank image.

The letter page and the A4 page keep their own proportions. Scale 1 of Letter is 612 by 792. Scale 1 of A4 is about 595 by 842. If you need the JPEG inside a new PDF, the JPG to PDF page will embed it, and the page size will follow the pixels. That round trip is lossy twice if you also used a low quality here.

Use the compressor when you want every page rebuilt and wrapped as a PDF again. Use this page when you want one page as a picture for a slide, a ticket, or a preview in a document that cannot embed PDF.

Wrap the JPEG again with JPG to PDF. Shrink every page inside a PDF with the PDF compressor.

A4 page at scale 2

Inputs: p2j-f: report-a4-3pages.pdf | p2j-page: 1 | p2j-scale: 2 | p2j-q: 80

On this page, take report-a4-3pages.pdf, then 1, then 2, then 80 and press Convert to JPG. Keep the JPEG only as a picture of that one page.

Result: PDF to JPG: page 1 of 3, 1191×1684 JPEG at quality 80. 21.7 KB The download is a picture of that page. Words in the picture cannot be selected.

Letter page at scale 1

Inputs: p2j-f: invoice-letter-2pages.pdf | p2j-page: 2 | p2j-scale: 1 | p2j-q: 60

On this page, take invoice-letter-2pages.pdf, then 2, then 1, then 60 and press Convert to JPG. Keep the JPEG only as a picture of that one page.

Result: PDF to JPG: page 2 of 2, 612×792 JPEG at quality 60. 6.5 KB The download is a picture of that page. Words in the picture cannot be selected.

Why is the A4 JPEG 1191 by 1684?

Scale 2 times the 595.28 by 841.89 point page, with the canvas rounding half points up.

Why is the Letter JPEG 612 by 792?

That invoice page is 612 by 792 points and the scale was 1, so the pixels match the points.

Can I copy a sentence out of the JPEG?

No. The 21.7 KB file and the 6.5 KB file are pictures of the page.

Does this wrap every page into a new PDF?

No. One page, one JPEG. The compressor is the page that builds a PDF of pictures.

What quality was the A4 sample?

80. The Letter sample used 60, which is why it is softer and only 6.5 KB.

Are encrypted PDFs rendered?

No. A password stops the render before a canvas is filled.