箭头绘制
在OpenCV中箭头的绘制依赖于arrowedLine() 该函数。该函数的一个重载函数如下：
Imgproc.arrowedLine(mat, pt1, pt2, color, thickness);
各参数解释如下：
-
mat
表示要在其上绘制箭头的图像的Mat对象。 -
pt1 和 pt2
两个Point对象，表示要绘制的箭头的点。其中pt1系起点，pt2系箭头点。 -
color
表示矩形颜色的标量对象(BGR)。 -
thickness
表示厚度。
Java代码（JavaFX Controller层）
public class Controller{
@FXML private Text fxText;
@FXML private ImageView imageView;
@FXML public void handleButtonEvent(ActionEvent actionEvent) throws IOException {
Node source = (Node) actionEvent.getSource();
Window theStage = source.getScene().getWindow();
FileChooser fileChooser = new FileChooser();
FileChooser.ExtensionFilter extFilter = new FileChooser.ExtensionFilter("PNG files (*.png)", "*.png");
fileChooser.getExtensionFilters().add(extFilter);
fileChooser.getExtensionFilters().add(new FileChooser.ExtensionFilter("JPG Files(*.jpg)", "*.jpg"));
File file = fileChooser.showOpenDialog(theStage);
runInSubThread(file.getPath());
}
private void runInSubThread(String filePath){
new Thread(new Runnable() {
@Override
public void run() {
try {
WritableImage writableImage = drawArrow(filePath);
Platform.runLater(new Runnable() {
@Override
public void run() {
imageView.setImage(writableImage);
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}
private WritableImage drawArrow(String filePath) throws IOException {
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
Mat src = Imgcodecs.imread(filePath);
Imgproc.arrowedLine(src, new Point(187,90), new Point(300,170), new Scalar(0,0,255),2);
MatOfByte matOfByte = new MatOfByte();
Imgcodecs.imencode(".jpg", src, matOfByte);
byte[] bytes = matOfByte.toArray();
InputStream in = new ByteArrayInputStream(bytes);
BufferedImage bufImage = ImageIO.read(in);
WritableImage writableImage = SwingFXUtils.toFXImage(bufImage, null);
return writableImage;
}
}
运行图
