phantomjs-render-large-page

PhantomJS can't render very tall or wide pages (more than 30k pixels). This library is a workaround to do it anyway.

Installation

You need imagemagick installed. In ubuntu, you can install it like this:

sudo apt-get update
sudo apt-get install imagemagick

You may need to change its policy at /etc/ImageMagick-6/policy.xml. These are the values that worked for the tests:

Windows is not supported.

Then

npm install phantomjs-render-large-page --save

Usage

Include it like this:

var renderLargePage = require('phantomjs-render-large-page').renderLargePage;

in you PhantomJS script.

renderLargePage is a phantomjs script that expects to be included from inside a phantomjs script, not called directly.

For example:

//screenshot.js
var renderLargePage = require('phantomjs-render-large-page').renderLargePage;
var page = require('webpage').create();

page.open('http://example.com', function () {
    renderLargePage(page, 'screenshot.png', function (error) {
        phantom.exit();
    });
});

Parameters

The renderLargePage function accepts the following parameters:

renderLargePage(page, filename, callback, [options]);

page is the PhantomJS page object to render.

filename is a file path where the output image will be rendered, as you would pass it to PhantomJS' render function

callback is a function that will be called on complete. callback will be passed an error parameter, that will only be present if there was an error.

options is an optional object with the following optional properties:

options.tmpDir a path to the directory where renderLargePage will write intermediate files. Defaults to process.env.TMPDIR (usually /tmp)

options.format it will be passed as the second parameter to PhantomJS' render function. Defaults to 'png'

options.quality it will be passed as the third parameter to PhantomJS' render function and to ImageMagick's -quality option. Defaults to 100.

options.limit Side of the square partial images rendered and stitched together later. Potentially useful to limit memory use. Defaults to 30720

For more information on supported image formats, quality, etc, see the PhantomJS docs for the render functionality:

http://phantomjs.org/api/webpage/method/render.html