Apply crop hints to a local image

Detect a crop region on a local image file.

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For detailed documentation that includes this code sample, see the following:

• Detect crop hints

Code sample

Go

Before trying this sample, follow the Go setup instructions in the Vision quickstart using client libraries. For more information, see the Vision Go API reference documentation.

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// detectCropHints gets suggested croppings the Vision API for an image at the given file path.
func detectCropHints(w io.Writer, file string) error {
	ctx := context.Background()

	client, err := vision.NewImageAnnotatorClient(ctx)
	if err != nil {
		return err
	}

	f, err := os.Open(file)
	if err != nil {
		return err
	}
	defer f.Close()

	image, err := vision.NewImageFromReader(f)
	if err != nil {
		return err
	}
	res, err := client.CropHints(ctx, image, nil)
	if err != nil {
		return err
	}

	fmt.Fprintln(w, "Crop hints:")
	for _, hint := range res.CropHints {
		for _, v := range hint.BoundingPoly.Vertices {
			fmt.Fprintf(w, "(%d,%d)\n", v.X, v.Y)
		}
	}

	return nil
}

Java

Before trying this sample, follow the Java setup instructions in the Vision quickstart using client libraries. For more information, see the Vision Java API reference documentation.

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import com.google.cloud.vision.v1.AnnotateImageRequest;
import com.google.cloud.vision.v1.AnnotateImageResponse;
import com.google.cloud.vision.v1.BatchAnnotateImagesResponse;
import com.google.cloud.vision.v1.CropHint;
import com.google.cloud.vision.v1.CropHintsAnnotation;
import com.google.cloud.vision.v1.Feature;
import com.google.cloud.vision.v1.Image;
import com.google.cloud.vision.v1.ImageAnnotatorClient;
import com.google.protobuf.ByteString;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class DetectCropHints {
  public static void detectCropHints() throws IOException {
    // TODO(developer): Replace these variables before running the sample.
    String filePath = "path/to/your/image/file.jpg";
    detectCropHints(filePath);
  }

  // Suggests a region to crop to for a local file.
  public static void detectCropHints(String filePath) throws IOException {
    List<AnnotateImageRequest> requests = new ArrayList<>();

    ByteString imgBytes = ByteString.readFrom(new FileInputStream(filePath));

    Image img = Image.newBuilder().setContent(imgBytes).build();
    Feature feat = Feature.newBuilder().setType(Feature.Type.CROP_HINTS).build();
    AnnotateImageRequest request =
        AnnotateImageRequest.newBuilder().addFeatures(feat).setImage(img).build();
    requests.add(request);

    // Initialize client that will be used to send requests. This client only needs to be created
    // once, and can be reused for multiple requests. After completing all of your requests, call
    // the "close" method on the client to safely clean up any remaining background resources.
    try (ImageAnnotatorClient client = ImageAnnotatorClient.create()) {
      BatchAnnotateImagesResponse response = client.batchAnnotateImages(requests);
      List<AnnotateImageResponse> responses = response.getResponsesList();

      for (AnnotateImageResponse res : responses) {
        if (res.hasError()) {
          System.out.format("Error: %s%n", res.getError().getMessage());
          return;
        }

        // For full list of available annotations, see http://g.co/cloud/vision/docs
        CropHintsAnnotation annotation = res.getCropHintsAnnotation();
        for (CropHint hint : annotation.getCropHintsList()) {
          System.out.println(hint.getBoundingPoly());
        }
      }
    }
  }
}

Node.js

Before trying this sample, follow the Node.js setup instructions in the Vision quickstart using client libraries. For more information, see the Vision Node.js API reference documentation.

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// Imports the Google Cloud client library
const vision = require('@google-cloud/vision');

// Creates a client
const client = new vision.ImageAnnotatorClient();

/**
 * TODO(developer): Uncomment the following line before running the sample.
 */
// const fileName = 'Local image file, e.g. /path/to/image.png';

// Find crop hints for the local file
const [result] = await client.cropHints(fileName);
const cropHints = result.cropHintsAnnotation;
cropHints.cropHints.forEach((hintBounds, hintIdx) => {
  console.log(`Crop Hint ${hintIdx}:`);
  hintBounds.boundingPoly.vertices.forEach((bound, boundIdx) => {
    console.log(`  Bound ${boundIdx}: (${bound.x}, ${bound.y})`);
  });
});

Python

Before trying this sample, follow the Python setup instructions in the Vision quickstart using client libraries. For more information, see the Vision Python API reference documentation.

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def detect_crop_hints(path):
    """Detects crop hints in an image."""
    from google.cloud import vision
    import io
    client = vision.ImageAnnotatorClient()

    with io.open(path, 'rb') as image_file:
        content = image_file.read()
    image = vision.Image(content=content)

    crop_hints_params = vision.CropHintsParams(aspect_ratios=[1.77])
    image_context = vision.ImageContext(
        crop_hints_params=crop_hints_params)

    response = client.crop_hints(image=image, image_context=image_context)
    hints = response.crop_hints_annotation.crop_hints

    for n, hint in enumerate(hints):
        print('\nCrop Hint: {}'.format(n))

        vertices = (['({},{})'.format(vertex.x, vertex.y)
                    for vertex in hint.bounding_poly.vertices])

        print('bounds: {}'.format(','.join(vertices)))

    if response.error.message:
        raise Exception(
            '{}\nFor more info on error messages, check: '
            'https://cloud.google.com/apis/design/errors'.format(
                response.error.message))

What's next

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