PDF.js displays PDF documents in really low resolution/ blurry almost. Is this how it is? - pdf.js

Question

I am trying to use PDF.js to view PDF documents. I find the display really low resolutions to the point of being blurry. Is there a fix?
// URL of PDF document
var url = "https://www.myFilePath/1Mpublic.pdf";
// Asynchronous download PDF
PDFJS.getDocument(url)
.then(function(pdf) {
return pdf.getPage(1);
})
.then(function(page) {
// Set scale (zoom) level
var scale = 1.2;
// Get viewport (dimensions)
var viewport = page.getViewport(scale);
// Get canvas#the-canvas
var canvas = document.getElementById('the-canvas');
// Fetch canvas' 2d context
var context = canvas.getContext('2d');
// Set dimensions to Canvas
canvas.height = viewport.height;
canvas.width = viewport.width;
// Prepare object needed by render method
var renderContext = {
canvasContext: context,
viewport: viewport
};
// Render PDF page
page.render(renderContext);
});

Answer 1

There are two things you can do. I tested and somehow it worked, but you will get a bigger memory consumption.
1 . Go to pdf.js and change the parameter MAX_GROUP_SIZE to like 8192 (double it for example) . Be sure to have your browser cache disable while testing.
You can force the getViewport to retrieve the image in better quality but like, I don't know how to say in English, compress it so a smaller size while showing:
// URL of PDF document
var url = "https://www.myFilePath/1Mpublic.pdf";
// Asynchronous download PDF
PDFJS.getDocument(url)
.then(function(pdf) {
return pdf.getPage(1);
})
.then(function(page) {
// Set scale (zoom) level
var scale = 1.2;
// Get viewport (dimensions)
var viewport = page.getViewport(scale);
// Get canvas#the-canvas
var canvas = document.getElementById('the-canvas');
// Fetch canvas' 2d context
var context = canvas.getContext('2d');
// Set dimensions to Canvas
var resolution = 2 ; // for example
canvas.height = resolution*viewport.height; //actual size
canvas.width = resolution*viewport.width;
canvas.style.height = viewport.height; //showing size will be smaller size
canvas.style .width = viewport.width;
// Prepare object needed by render method
var renderContext = {
canvasContext: context,
viewport: viewport,
transform: [resolution, 0, 0, resolution, 0, 0] // force it bigger size
};
// Render PDF page
page.render(renderContext);
});
enter code here
Hope it helps!

Answer 2

This code will help you, my issue was pdf was not rendering in crisp quality according with the responsiveness. So i searched , and modified my code like this. Now it works for rendering crisp and clear pdf according to the div size you want to give. `var loadingTask = pdfjsLib.getDocument("your_pdfurl");
loadingTask.promise.then(function(pdf) {
console.log('PDF loaded');
// Fetch the first page
var pageNumber = 1;
pdf.getPage(pageNumber).then(function(page) {
console.log('Page loaded');
var container = document.getElementById("container") //Container of the body
var wrapper = document.getElementById("wrapper");//render your pdf inside a div called wrapper
var canvas = document.getElementById('pdf');
var context = canvas.getContext('2d');
const pageWidthScale = container.clientWidth / page.view[2];
const pageHeightScale = container.clientHeight / page.view[3];
var scales = { 1: 3.2, 2: 4 },
defaultScale = 4,
scale = scales[window.devicePixelRatio] || defaultScale;
var viewport = page.getViewport({ scale: scale });
canvas.height = viewport.height;
canvas.width = viewport.width;
var displayWidth = Math.min(pageWidthScale, pageHeightScale);;
canvas.style.width = `${(viewport.width * displayWidth) / scale}px`;
canvas.style.height = `${(viewport.height * displayWidth) / scale}px`;
// Render PDF page into canvas context
var renderContext = {
canvasContext: context,
viewport: viewport
};
var renderTask = page.render(renderContext);
renderTask.promise.then(function() {
console.log('Page rendered');
});
});
}, function(reason) {
// PDF loading error
console.error(reason);
});`