joomla/image

Joomla Image Package

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Language: PHP

1.1.5 2014-08-23 20:02 UTC

README

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This package comprises of 2 main classes, Image and ImageFilter which has 8 filter sub-classes that it can use to apply a desired filter to your image. Image depends on the GD php extension to be loaded on your server. More information on GD can be found at: http://php.net/manual/en/book.image.php

Manipulating images in raw PHP using the GD image* functions requires a lot of boilerplate code. The intent of this package is to handle those requirements and make it simple for developers to accomplish those tasks through easy to use (and remember) methods.

All classes in this package are supported by the auto-loader so can be invoked at any time.

Construction

When creating a new Image object, the constructor will check that the gd extension is loaded, and throw a RuntimeException if it is not.

The constructor takes a single optional $source parameter. This argument can be one of two things:

  • A variable containing an existing, valid image resource created using a imagecreate* method.
  • A string containing a valid, absolute path to an image

If you choose the first option, the class sets the protected property $handle to the provided image resource. If you choose the second option, the class will call the loadFile method, passing along the $source parameter.

use Joomla\Image\Image;

// Creating a new Image object, passing it an existing handle.
$resource = imagecreate(100, 100);
$image = new Image($resource);

// Creating a new Image object, passing it an image path
$image = new Image(JPATH_ROOT . '/media/com_foo/images/uploads/bar.png');

// Creating a new Image object then manually calling `loadFile`
$image = new Image;
$image->loadFile(JPATH_ROOT . '/media/com_foo/images/uploads/bar.png');

Usage

Keep in mind that most public methods return a Image instance with a valid image handle for easy method chaining. The examples for each method will break each method call out to be able to comment on what the code is doing, but production code can be chained like so (if you prefer):

use Joomla\Image\Image;

$image = new Image();
$image->loadFile(JPATH_ROOT . '/path/to/image.png')
    ->crop(600, 250)
    ->toFile(JPATH_ROOT . '/tmp/image.png');

Since Platform version 12.3, there is a new destroy() method that gets called in appropriate places throughout the class which runs the imagedestroy function to free memory associated with an image handle. This method is called before each time an image handle is replaced (when $createNew is set to false) as well as in the class __descruct method as a final cleanup.

The resize method

Accepted Parameters

  • $width: The width of the resized image in pixels or a percentage.
  • $height: The height of the resized image in pixels or a percentage.
  • $createNew: If true the current image will be cloned, resized and returned; else the current image will be resized and returned.
  • $scaleMethod: Which method to use for scaling

Example: Using Image::resize() to generate a resized image.

use Joomla\Image\Image;

// Create our image object
$image = new Image(JPATH_ROOT . '/media/com_foo/images/uploads/bar.png');

// Resize the image using the SCALE_INSIDE method
$image->resize(300, 150, true, Image::SCALE_INSIDE);

// Write it to disk
$image->toFile(JPATH_ROOT . '/tmp/bar_resized.png');
The crop method

Accepted Parameters

  • $width: The width of the image section to crop in pixels or a percentage.
  • $height: The height of the image section to crop in pixels or a percentage.
  • $left: The number of pixels from the left to start cropping.
  • $top: The number of pixels from the top to start cropping.
  • $createNew: If true the current image will be cloned, cropped and returned; else the current image will be cropped and returned.

Example: Using Image::crop() to generate a cropped image.

use Joomla\Image\Image;

// Create our image object
$image = new Image(JPATH_ROOT . '/media/com_foo/images/uploads/bar.png');

// Crop the image to 150px square, starting 10 pixels from the left, and 20 pixels from the top
$image->crop(150, null, 10, 20);

// Write it to disk
$image->toFile(JPATH_ROOT . '/tmp/bar_cropped.png');

To crop in image after resizing it to maintain proportions use cropResize method with familiar arguments $width, $height and $createNew.

The createThumbs method

Accepted Parameters

  • $thumbSizes: String or array of strings. Example: $thumbSizes = array('150x75','250x150');
  • $creationMethod: See Resize Methods below.
  • $thumbsFolder: Destination for thumbnails. Passing null generates a thumbs folder in the loaded image's containing folder.

Example: Using Image::createThumbs() to generate thumbnails of an image.

use Joomla\Image\Image;

// Set the desired sizes for our thumbnails.
$sizes = array('300x300', '64x64', '250x125');

// Create our object
$image = new Image(JPATH_ROOT . '/media/com_foo/images/uploads/uploadedImage.jpg');

// Create the thumbnails
$image->createThumbs($sizes, Image::SCALE_INSIDE);

In this example, we use the createThumbs method of Image. This method takes 2 parameters. The first parameter can be a string containing a single size in WIDTHxHEIGHT format, or it can be an array of sizes in the format (as shown in the example). The second parameter specifies the resize method. (See Resize Methods below)

To receive Image instances without saving them to disk, use generateThumbs method with arguments $thumbSizes and $creationMethod.

Resize Methods

The resize, createThumbs and generateThumbs methods take an optional parameter that defines what method to use when scaling an image. This parameter can be one of the following:

  • Image::SCALE_FILL - Gives you a thumbnail of the exact size, stretched or squished to fit the parameters.
  • Image::SCALE_INSIDE - Fits your thumbnail within your given parameters. It will not be any taller or wider than the size passed, whichever is larger.
  • Image::SCALE_OUTSIDE - Fits your thumbnail to the given parameters. It will be as tall or as wide as the size passed, whichever is smaller.
  • Image::SCALE_FIT - Fits your thumbnail to given boundaries maintaining aspect ratio. Result will be aligned vertically to center and horizontally to middle.
  • Image::CROP - Gives you a thumbnail of the exact size, cropped from the center of the full sized image.
  • Image::CROP_RESIZE - As above, but gives a clean resize and crop from center.
The toFile method

Accepted Parameters

  • $path: The filesystem path to save the image. When null, the raw image stream will be outputted directly.
  • $type: The image type to save the file as (IMAGETYPE_GIF|IMAGETYPE_PNG|IMAGETYPE_JPEG).
  • $options: The image type options to use in saving the file. Use quality key to set compression level (0..9 for PNGs and 0..100 for JPEGs)

Example: Using Image::toFile() to save the image as JPEG with 65 compression level

use Joomla\Image\Image;

// Create our object
$image = new Image(JPATH_ROOT . '/media/com_foo/images/uploads/bar.png');

// Write to disk
$image->toFile(JPATH_ROOT . '/tmp/bar.jpg', IMAGETYPEJPEG, array('options' => 65));

Example: Using Image::toFile() to retrieve data blob of an image.

use Joomla\Image\Image;

// Create our object
$image = new Image(JPATH_ROOT . '/media/com_foo/images/uploads/bar.png');

// Enable output buffering
ob_start();

// Retrieve data blob
$image->toFile(null, IMAGETYPE_PNG);
$imageBlob = ob_get_clean();

Installation via Composer

Add "joomla/image": "~1.0" to the require block in your composer.json and then run composer install.

{
    "require": {
        "joomla/image": "~1.0"
    }
}

Alternatively, you can simply run the following from the command line:

composer require joomla/image "~1.0"