Optimize Plone content images for Web usage

## Introduction

This Plone add-on perform (lossless) optimization image content types, using external processes.

## How it works

Your site users will continue to load image contents normally, but the data loaded will be taken from external optimization software (that must live on the server) for executing image lossless transformation.

In this way the final result will be commonly an smaller image, loaded quickly by browsers.

By default adding this plugin is not enough. You must include all supported software you have installed on you server (or limiting it to what you want to use).

To do this, include a proper zcml file in your buildout configuration:

[instance]
...
eggs =
Plone
...
collective.optimage

zcml =
...
collective.optimage:wantedoptimizator1.zcml
collective.optimage:wantedoptimizator2.zcml
...

All wantedoptimizatorX entries must be one of the supported software below. An example:

zcml =
collective.optimage:jpegoptim.zcml
collective.optimage:optipng.zcml

To include them all (excluded pngout), just include the “all.zcml”.

### Supported software

Right now this product supports those command line tools:

jpegoptim

For JPEG optimization - http://freecode.com/projects/jpegoptim

jpegtran

For JPEG optimization - http://jpegclub.org/jpegtran/

gifscicle

For GIT optimization - http://www.lcdf.org/gifsicle/

optipng

For PNG optimization - http://optipng.sourceforge.net/

pngcrush

For PNG optimization - http://pmt.sourceforge.net/pngcrush/

pngout (slow)

If you like to provide support for additional software, you can do it using ZCA in your own products. You need to provide a named adapter for the IOptimageProvider interface.

An example:

<adapter
name="yournewsoftware"
for="plone.app.blob.interfaces.IATBlobImage
zope.publisher.interfaces.browser.IHTTPRequest"
provides="collective.optimage.interfaces.IOptimageProvider"
/>

from zope.interface import implements
from collective.optimage.interfaces import IOptimageProvider

"""Optimize using yournewsoftware"""
implements(IOptimageProvider)

for_image = 'jpeg'

def optimize(self):
// do stuff, calling external process

Note that you must fill the for_image providing the image type you want to threat with your plugin.

## Tips and know issues

### Command line tool position

Right now this product will try to run all of the software given above simply calling them. If the program is not available at the user that run Zope process you could like to manually specify where is it. The same if the software has been manually installed (for example: if you manually downloaded and installed it inside a buildout installation and not system wide).

To do this, provide a environment var called “SOFTWARENAME_PATH”. An example:

[instance]

...

environment-vars =
...
JPEGOPTIM_PATH /opt/local/bin/jpegoptim

### Content types

Right now Plone Image content type is the only one supported. Unluckily Plone News item is still not using Zope BLOB support so it will not gain any optimization.

### Performance

Operations done by external processes are synchronous, so blocking the Zope thread. This will lower your site performance when an editor is providing new images (or modifying existings ones).

You can make them quicker (but less efficient), playing with configuration options.

### On performance (again)

Right now optimization are done after the image has been loaded on Plone. An event is fired after the image source change, then the image is put on a temp file and then processed. After that the optimized image is loaded again.

This is also done for all scaled image versions.

This is inefficient, so probably will change in future, however is the only way I found without monkey-patch Plone.

## Changelog

0.1.0 (2012-06-30)

• Initial release

## Project details

Uploaded source