open-thumbnailer
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An open source thumbnailer framework
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Markdown
A friendly [node.js](www.nodejs.org) JavaScript wrapper around [phantomjs](http://phantomjs.org/) that lets you create webpage thumbnails in a headless environment with a few lines of code. There are generally several things you want to do when creating a thumbnail:
- Render the webpage as a PNG or JPG
- Control the quality level of your saved thumbnail (for JPGs)
- Resize the thumbnail
- Crop the thumbnail
- Copy / Delete / Rename thumbnails
The open-thumbnailer library makes all of this very easy.
##Installation
`npm install open-thumbnailer`
To use a lot of the functionality in the library you will need to install [graphicsmagick](http://www.graphicsmagick.org) as well.
##Examples Thumbnails
Here are some example thumbnails generated by this library:
To see some more thumbnails, look in the examples/thumbs directory. You can run the examples/top.js example and generate these thumbs for yourself.
##Thumnailer Examples
###Supported File Formats
You can save thumbnails as PNG of JPG files. For JPG files you can also specify a quality value in the fromUrl options that affects the JPG quality.
To create a thumbnail it's really just a few lines of code. For example to create a thumbnail for www.imdb.com you would do:
```javascript
var OT = require('open-thumbnailer'),
thumbnailer = new OT.Thumbnailer();
thumbnailer.fromUrl(
'http://www.imdb.com',
__dirname + '/imdb.com.jpg',
function(error, thumbnail) {
if (error) {
console.dir(error);
return;
}
console.dir(thumbnail.getInfo());
}
);
```
At any point you can cancel an in progress thumbnail
```
thumbnailer.cancel();
```
There are various options you can specify to the thumbnailer when creating a thumb:
```javascript
var OT = require('open-thumbnailer'),
thumbnailer = new OT.Thumbnailer();
thumbnailer.fromUrl(
'http://www.imdb.com',
// To save as a PNG, simply change the file extension to PNG
__dirname + '/imdb.com.jpg',
{
// A number between 0 and 100 that specifies the quality of the jpg thumb.
// Only applies if you are creating jpgs, not pngs
quality: 75,
// If you don't specify an extension on the output path, then you must specify
// the format here, if you don't want the default of jpg. Can be jpg, jpeg or png.
// This value will be ignored if the output path has an extension already set on
// it of png | jpg | jpeg
format: 'jpg',
// Can be true, which will use a simple internal console.log method
// to log status, or you can provide your own log object e.g.
log: {
verbose: function(message) { console.log(message); },
error: function(message, error) { console.error(JSON.stringify(error))}
},
// The amount of time to wait before cancelling the thumbnail. If a page
// is taking a long time to load you may want to cancel
timeout: 60,
// The amount of time (in seconds) to wait after the page loads before actually
// trying to render the page. There may be cases where the page loads content
// asyncronously and if you render straight away on load the page may not have
// all the content.
delay: 10,
// The size of the window when the page is loaded. This is not a crop size it
// is the size of the browser window to use when loading the content. Content loaded
// outside of these values will still be rendered in the final thumb. If you want
// to crop then use the crop value as specified below
viewport: { width: 1024, height: 768 },
// The part of the page to render. The interesting part here is cropToPage, if this
// is false then if the rendered webpage is smaller than the crop region the thumbnail
// will still be as big as the crop region with pixels filled in black, however if you
// set cropToPage:true, then if the webpage is smaller than the crop size the thumbnail
// will be the same size as the page.
crop: { top:0, left:0, width: 1024, height: 400, cropToPage: true }
},
function(error, thumbnail) {
if (error) {
console.dir(error);
return;
}
console.dir(thumbnail.getInfo());
}
);
```
Once you have generated a thumbnail, you will have a Thumbnail instance, there are several methods available to you:
```javascript
var info = thumb.getInfo();
console.log(info.width + 'x' + info.height + ' at ' + info.path + ' ' + info.size + ' bytes');
```
```javascript
thumb.destroy(function(error) {
console.dir(error);
});
```
```javascript
thumb.copy('some-new-file-name.jpg', function(error, copyOfThumb) {
console.log(copyOfThumb.getInfo().path);
});
```
```javascript
thumb.move('new-file-location.jpg', function(error) {
console.dir(error);
});
```
```javascript
thumb.resize(
{
// scales the thumbnail to 400 pixels wide, the aspect ratio of the clip
// will be maintained
scaleToWidth: 400,
// scales the thumbnail to 600 pixels tall. Only specify one of scaleToWidth
// and scaleToHeight, if both are specified the behaviour is unspecified
scaleToHeight: 600,
// Optional - if not specified the thumb will be resized and the original
// thumb variable points to the resized thumb. If you specify a targetPath
// then a copy of the thumb is made and resized and the copied thumb is
// returned in the callback
targetPath: 'some-new-file.jpg',
// crops the thumbnail AFTER it has been resized, so for example if you set
// scaleToWidth to 400 and wanted a square thumbnail, you could then crop the
// height to 400 pixels here to make the output square
crop: { top:0, left: 0, width: 400, height: 400 }
},
function(error, resizedThumb) {
// NOTE: resizedThumb will be null if you did not specify a targetpath
// in the options
}
);
```
1. Install GraphicsMagick http://www.graphicsmagick.org/ (sudo port install graphicsmagick)
```shell
git clone https://github.com/markdaws/open-thumbnailer.git
cd open-thumbnailer
npm install
npm test
node examples/top.js