Strange getting width of page in phantomjs - phantomjs

Question

here is the script code:
var page = require('webpage').create();
page.paperSize = {
format: 'A4',
orientation: "landscape"
};
page.open('http://www.google.com', function () {
var arr = page.evaluate(function () {
var pageWidth = document.body.clientWidth;
var pageHeight = document.body.clientHeight;
return [pageWidth, pageHeight];
});
console.log('pagwWidth: ' + arr[0] + '; pageHeight: ' + arr[1]);
page.render('google.pdf');
phantom.exit();
});
I'm trying to get clientWidth and clientHeight of document.body page. When I exec this script I'm getting the folowing values:
pagwWidth: 400; pageHeight: 484
Why is the width above is 400px? I think I should be wider.
Thank you for the reply. But then I don't understand the following thing. When I use viewportSize = {width: 1024, height: 800}
var page = require('webpage').create();
page.paperSize = {
format: 'A4',
orientation: "landscape"
};
page.viewportSize = {width: 1024, height: 800};
page.open('http://www.google.com', function () {
page.render('google.pdf');
phantom.exit();
});
I get the following file:
But if I use viewportSize = {width: 400, height: 400}
var page = require('webpage').create();
page.paperSize = {
format: 'A4',
orientation: "landscape"
};
page.viewportSize = {width: 400, height: 400};
page.open('http://www.google.com', function () {
page.render('google.pdf');
phantom.exit();
});
I get the same:
So I don't understand how does viewportSize affect to the view?

Answer 1

The document is affected by the viewport size and not by the paper size. Think along this line, how a web page looks like in your web browser has nothing to do with your current printer setting.
Use viewportSize if you want to influence the page layout:
page.viewportSize = { width: 1024, height: 800 };