Focus points

April 11, 2024 01:54 PM

1 min read

A focus point is an image’s ideal vertical and horizontal center after cropping. You can specify focus points using the following techniques:

Using Brightspot’s image editor.
Integrating the OpenIMAJ library.
Integrating a cloud service such as Amazon Rekognition .

If you know that an image’s subject is always centered in the middle (as in time-lapse photography), you can return that coordinate in a Focus object. This technique ensures Brightspot generates crops around the image’s native center.

Class for setting focus point around image’s physical center

import com.psddev.cms.image.Focus;
import com.psddev.cms.image.FocusCalculator;
import com.psddev.dari.util.ObjectUtils;
import com.psddev.dari.util.StorageItem;

public class CenterFocusCalculator implements FocusCalculator { 

    @Override
    public Focus getFocus(StorageItem storageItem) {
        Map<String, Object> metaData = storageItem.getMetadata();
        
        double imageWidth = ObjectUtils.to(double.class, metaData.get("width")); 
        double imageHeight = ObjectUtils.to(double.class, metaData.get("height"));
        Focus centerFocus = new Focus(imageWidth / 2, imageHeight / 2);

        System.out.println("Focus, x-coordinate " + centerFocus.getX()); 
        System.out.println("Focus, y-coordinate " + centerFocus.getY());
        return centerFocus;
    }

}

Declares this view model implements the FocusCalculator interface.
Retrieves the image’s width and height from the metadata, divides each in half, and returns both values in a Focus object.
Prints the focus point to the console.

Console output from class CenterFocusCalculator

Focus, x-coordinate 200.0
Focus, y-coordinate 131.0