Dynamic metadata is metadata added to a source image that changes the image identifying hash. Currently the only dynamic metadata supported is the subject area.
To add dynamic metadata to a source image, you need to provide the organization, the identifying hash of the image, the name of the dynamic metadata and the values to add. Do this by making a PUT request to https://api.rokka.io/sourceimages/{organization}/{hash}/meta/dynamic/{name}
rokka will generate a new identifying hash for the image and delete the old identifying hash. The new location of the image will be returned in the Location header of the response.
In the following example, we are adding a subject area to an image.
curl -H 'Content-Type: application/json' -X PUT 'https://api.rokka.io/sourceimages/testorganization/0dcabb778d58d07ccd48b5ff291de05ba4374fb9/meta/dynamic/SubjectArea' -d '{
"width": 20,
"height": 20,
"x": 0,
"y": 0
}'
use Rokka\Client\Core\DynamicMetadata\SubjectArea;
$client = \Rokka\Client\Factory::getImageClient('testorganization', 'apiKey', 'apiSecret');
$hash = '0dcabb778d58d07ccd48b5ff291de05ba4374fb9';
$dynamicMetadata = new SubjectArea(0, 0, 30, 230);
$newHash = $client->setDynamicMetadata($dynamicMetadata, $hash);
echo 'Updated subject area. New image hash: ' . $newHash . PHP_EOL;
To delete dynamic metadata from a source image, you need to provide the organization, the identifying hash of the image and the name of the dynamic metadata. Do this by making a DELETE request to https://api.rokka.io/sourceimages/{organization}/{hash}/meta/dynamic/{name}
rokka will generate a new identifying hash for the image and delete the old identifying hash. The new location of the image will be returned in the Location header of the response.
curl -H 'Content-Type: application/json' -X DELETE 'https://api.rokka.io/sourceimages/testorganization/0dcabb778d58d07ccd48b5ff291de05ba4374fb9/meta/dynamic/SubjectArea'
The subject area of an image is a box defined by its width, height and the coordinates of its
starting point (top-left corner).
Setting the subject area of an image allows the Crop operation (when used with the auto anchor),
to center the cropping box around the defined SubjectArea.
For further details see the Crop operation
You can use the SubjectArea to specify the most important part of the image, the part that should be retained at any size.
x (required): Integer. The x-offset of the starting point, in pixels.y (required): Integer. The y-offset of the starting point, in pixels.width: Integer. The width of the subject area, in pixels. The default value is 1.height: Integer. The height of the subject area, in pixels. The default value is 1.