java - Javafx：用鼠标在 ImageView 上绘图

Question

在 ImageView 上用鼠标绘图的任何方式..我不知道，例如使用画布？谢谢

Answer 1

我来到这个是一个很好的解决我的问题..不是吗？

    AnchorPane anchorRoot;
    double initX;
    double initY;
    ImageView iv = new ImageView(image);
    final double maxX = iv.getImage().getWidth();
    final double maxY = iv.getImage().getHeight();

    anchorRoot.getChildren().add(iv);

    iv.setOnMousePressed(new EventHandler<MouseEvent>() {
        @Override
        public void handle(MouseEvent me) {
            //System.out.println("Clicked, x:" + me.getSceneX() + " y:" + me.getSceneY());
            //the event will be passed only to the circle which is on front
            initX = me.getSceneX();
            initY = me.getSceneY();
            me.consume();
        }
    });
    iv.setOnMouseDragged(new EventHandler<MouseEvent>() {
        @Override
        public void handle(MouseEvent me) {
            //System.out.println("Dragged, x:" + me.getSceneX() + " y:" + me.getSceneY());
            if (me.getSceneX() < maxX && me.getSceneY() < maxY) {
                Line line = new Line(initX, initY, me.getSceneX(), me.getSceneY());
                line.setFill(null);
                line.setStroke(Color.RED);
                line.setStrokeWidth(2);
                anchorRoot.getChildren().add(line);
            }

            initX = me.getSceneX() > maxX ? maxX : me.getSceneX();
            initY = me.getSceneY() > maxY ? maxY : me.getSceneY();
        }
    });

Answer 2

您可以使用 javafx 轻松完成此操作（未显示设计文件（fxml），仅显示代码的工作原理）...

package sample;

import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.image.PixelWriter;
import javafx.scene.image.WritableImage;
import javafx.scene.paint.Color;
import java.net.URL;
import java.util.ResourceBundle;

public class Controller implements Initializable{

    @FXML private ImageView img;

    @Override
    public void initialize(URL location, ResourceBundle resources) {

        Image[] i={null};
        i[0]=new Image("file:\\"+"C:\\Users\\Ragib\\Desktop\\a.jpg");
        img.setFitHeight(i[0].getHeight());
        img.setFitWidth(i[0].getWidth());
        img.setImage(i[0]);

        img.setOnMouseDragged(event -> {
            double x=event.getX();
            double y=event.getY();
            WritableImage wi=new WritableImage(i[0].getPixelReader(),(int)i[0].getWidth(),(int)i[0].getHeight());
            PixelWriter pw=wi.getPixelWriter();
            pw.setColor((int)x,(int)y,new Color(0,0,0,1));
            i[0]=wi;
            img.setImage(i[0]);
        });
    }
}