Important notice: the development of WideImage 1.0 branch is discontinued.
Please visit
http://wideimage.sourceforge.net for the new version of library and documentation.
This web site will remain accessible to serve as documentation for the old versions of the library.
For help on migration, please refer
to the
migration
guide.
Custom Image Operations
If you want to use a custom image operation, you only have to declare an operation class somewhere in your code or autoloader. The class has to conform to a few simple rules.
Naming the class
You have to name the class properly:
wioOPERATION_NAME, for example wioMyOperation.
WideImage will automatically create and use the operation.
Methods
In order for the operation to work, two methods must be defined properly; a parameterless constructor and the execute method.
execute()
- Signature: execute($image[, custom parameters])
- Parameters:
- $image wiImage - The object to perform the operation on.
- custom parameters can be defined. They are passed from the user call.
- Return value must be a valid wiImage object (this means wiTrueColorImage or wiPaletteImage).
Note: The operation isn't supposed to modify the source image, it's supposed to return a newly created and modified image. This is not necessary, but it's a good and expected practice.
Example of an operation
Let's define a simple operation that draws a number of white points at random location on the image.
class wioDrawWhiteDots
{
function execute
($image,
$n =
5)
{
// make a copy
$new =
$image->
copy();
// allocate a white color
$white =
$new->
allocateColor(255,
255,
255);
// draw a point $n times
for ($i =
0;
$i <
$n;
$i++
)
{
// random position
$x =
rand(0,
$image->
getWidth() -
1);
$y =
rand(0,
$image->
getHeight() -
1);
// draw the point
$new->
setRGBAt($x,
$y,
$white);
}
return $new;
}
}
And now let's use it:
$img = wiImage::load('/path/to/image.png');
// let's do it
$modified = $img->drawWhiteDots();
// let's draw 100 white points instead of 5
$modified = $img->drawWhiteDots(100);
// of course, the custom operation can be chained as well
$modified = $img->resize(200, 200)->drawWhiteDots(70)->rotate(45);
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