how does Google implement online PDF reader?

Question

hello

I am somewhat ignorant about modern web technology, last have played with them way back in CGI days. I am curious as to how Google implements their PDF reader online, can you please explain it briefly? from what I can tell it is not a simple webpage/image

Thanks

Answer 1

It appears to be JavaScript with the document shown as an image.

Most likely a server side process converts the document to an image and the client-side viewer displays the image in a way that makes it look like a document.

Answer 2

This is just a guess since I don't work for Google. They will have a script, process, that would read the PDF document, read each page and convert the page into images, then they some javascript control that capture location of mouse for selection of text. May be use OCR to recognize the text or just grab it from the document.