High-level PHP binding for libvips

A high-level interface to the libvips image processing library. This module builds upon the vips extension, see:

https://github.com/jcupitt/php-vips-ext

You'll need to install that first. It's tested on Linux, OS X should work, Windows would need some work, but should be possible.

libvips is fast and it can work without needing to have the entire image loaded into memory. Programs that use libvips don't manipulate images directly, instead they create pipelines of image processing operations starting from a source image. When the end of the pipe is connected to a destination, the whole pipeline executes at once, streaming the image in parallel from source to destination in a set of small fragments.

See the benchmarks at the official libvips website. There's also a vips-php-bench repository with benchmarks against imagick and gd. There's a handy blog post explaining how libvips opens files which gives some more background.

Example

#!/usr/bin/env php
<?php
use Jcupitt\Vips;

$image = Vips\Image::newFromFile($argv[1]);

echo "width = ", $image->width, "\n";

$image = $image->invert();

$image->writeToFile($argv[2]);
?>

You'll need this in your composer.json:

    "require": {
            "jcupitt/vips" : "@dev"
    }

And run with:

$ composer install
$ ./try1.php ~/pics/k2.jpg x.tif

See examples/.

Almost all methods return a new image for the result, so you can chain them. For example:

$image = $image->more(12)->ifthenelse(255, $image);

will make a mask of pixels greater than 12, then use the mask to set pixels to either 255 or the original image.

You use long, double, array and image as parameters. For example:

$image = $image->add(2);

to add two to every band element, or:

$image = $image->add([1, 2, 3]);

to add 1 to the first band, 2 to the second and 3 to the third. Or:

$image = $image->add($image2);

to add two images. Or:

$image = $image->add([[1, 2, 3], [4, 5, 6]]);

To make a 2 x 3 image from the array, then add that image to the original.

Almost all methods can take an optional final argument, an array of options. For example:

$image->writeToFile("fred.jpg", ["Q" => 90]);

There are around 300 operations in the library, see the vips docs for an introduction:

http://www.vips.ecs.soton.ac.uk/supported/current/doc/html/libvips/

How it works

The vips extension defines a simple but ugly way to call any libvips operation from PHP. It uses libvips' own introspection facilities and does not depend on anything else (so no gobject-introspection, for example). It's a fairly short 1,600 lines of C.

This module is a PHP layer over the ugly vips extension that tries to make a nice interface for programmers. It uses __call() and __get() to make all libvips operations appear as methods, and all libvips properties as properties of the PHP Vips\Image class.

Test and install

$ phpcs src
$ composer install
$ vendor/bin/phpunit
$ vendor/bin/phpdoc