JavaFX resize canvas in fxml

Question

I\'m trying to resize a canvas in Javafx. I am using scene builder and fxml. So far, when the user clicks on the canvas the canvas turns black, and when I resize the screen

Answer 1

If you want to resize canvas in fxml and presumably redraw its contents afterwards, the absolute minimum set is something like this:

test.fxml

TestController.java

package test;

import javafx.fxml.FXML;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;

public class TestController {
  @FXML
  private Canvas canvas;

  @FXML
  private void redraw() {
    double w=canvas.getWidth();
    double h=canvas.getHeight();
    GraphicsContext gc=canvas.getGraphicsContext2D();
    gc.clearRect(0, 0, w, h);
    gc.beginPath();
    gc.rect(10, 10, w-20, h-20);
    gc.stroke();
  }
}

---

Wrapping (it is not part of the functionality, just provided for completeness)

Test.java

package test;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class Test extends Application {
  @Override
  public void start(Stage primaryStage) throws Exception {
    FXMLLoader loader=new FXMLLoader(getClass().getResource("test.fxml"));
    Parent root=loader.load();
    primaryStage.setTitle("Test");
    primaryStage.setScene(new Scene(root));
    primaryStage.show();
  }

  public static void main(String[] args) {
    launch(args);
  }
}

the test package is there for allowing modular magic,

module-info.java

module cnvtest {
  requires transitive javafx.graphics;
  requires javafx.fxml;
  opens test to javafx.fxml;
  exports test;
}

and there are really no more files.