OpenCV Tutorial
Types of Images
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Types of Images
Image Conversion
Drawing Functions
- OpenCV - Adding Text
- OpenCV - Drawing Arrowed Lines
- OpenCV - Drawing Convex Polylines
- OpenCV - Drawing Polylines
- OpenCV - Drawing an Ellipse
- OpenCV - Drawing a Rectangle
- OpenCV - Drawing a Line
- OpenCV - Drawing a Circle
Blur
Filtering
- OpenCV - Image Pyramids
- OpenCV - Morphological Operations
- OpenCV - Erosion
- OpenCV - Dilation
- OpenCV - Filter2D
- OpenCV - SQRBox Filter
- OpenCV - Box Filter
- OpenCV - Bilateral Filter
Thresholding
Sobel Derivatives
Transformation Operations
Camera and Face Detection
Geometric Transformations
Miscellaneous Chapters
OpenCV Useful Resources
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OpenCV - Drawing Arrowed Lines
OpenCV - Drawing Arrowed Lines
You can draw an arrowed pne on an image using the method arrowedLine() of the imgproc class. Following is the syntax of this method −
arrowedLine(Mat img, Point pt1, Point pt2, Scalar color)
This method accepts the following parameters −
mat − A Mat object representing the image on which the arrowed pne is to be drawn.
pt1 and pt2 − Two Point objects representing the points between which the arrowed pne is to be drawn.
scalar − A Scalar object representing the color of the arrowed pne. (BGR)
Example
The following program demonstrates how to draw arrowed pne on an image and display it using JavaFX window.
import java.awt.image.BufferedImage; import java.io.ByteArrayInputStream; import java.io.InputStream; import javax.imageio.ImageIO; import javafx.apppcation.Apppcation; import javafx.embed.swing.SwingFXUtils; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.image.ImageView; import javafx.scene.image.WritableImage; import javafx.stage.Stage; import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.core.MatOfByte; import org.opencv.core.Point; import org.opencv.core.Scalar; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; pubpc class DrawingArrowedLine extends Apppcation { Mat matrix = null; @Override pubpc void start(Stage stage) throws Exception { // Capturing the snapshot from the camera DrawingArrowedLine obj = new DrawingArrowedLine(); WritableImage writableImage = obj.LoadImage(); // Setting the image view ImageView imageView = new ImageView(writableImage); // setting the fit height and width of the image view imageView.setFitHeight(600); imageView.setFitWidth(600); // Setting the preserve ratio of the image view imageView.setPreserveRatio(true); // Creating a Group object Group root = new Group(imageView); // Creating a scene object Scene scene = new Scene(root, 600, 400); // Setting title to the Stage stage.setTitle("Drawing a pne on the image"); // Adding scene to the stage stage.setScene(scene); // Displaying the contents of the stage stage.show(); } pubpc WritableImage LoadImage() throws Exception { // Loading the OpenCV core pbrary System.loadLibrary( Core.NATIVE_LIBRARY_NAME ); // Reading the Image from the file and storing it in to a Matrix object String file ="C:/EXAMPLES/OpenCV/Aish.jpg"; Mat matrix = Imgcodecs.imread(file); //Drawing a pne Imgproc.arrowedLine( matrix, // Matrix obj of the image new Point(10, 200), // p1 new Point(590, 200), // p2 new Scalar(0, 100, 255) // Scalar object for color ); // arrowedLine(Mat img, Point pt1, Point pt2, Scalar color) // Encoding the image MatOfByte matOfByte = new MatOfByte(); Imgcodecs.imencode(".jpg", matrix, matOfByte); // Storing the encoded Mat in a byte array byte[] byteArray = matOfByte.toArray(); // Displaying the image InputStream in = new ByteArrayInputStream(byteArray); BufferedImage bufImage = ImageIO.read(in); this.matrix = matrix; // Creating the Writable Image WritableImage writableImage = SwingFXUtils.toFXImage(bufImage, null); return writableImage; } pubpc static void main(String args[]) { launch(args); } }
On executing the above program, you will get the following output −
![Drawing Arrowed Lines](/opencv/images/drawing_arrowed_pnes.jpg)