设置画布布局

Question

如何在场景中间获得白色矩形。我想保留自己的代码以及它的高度和宽度。可能它应该用于设置X和Y布局。但是我不知道怎么做。当我设置它们时，它会从左上角调整它的大小。

代码：

Pane paneCanvas = new Pane(); 

      final Canvas canvas = new Canvas(); 
      paneCanvas.setStyle("-fx-background-color: white;"); 
      canvas.setHeight(32); 
      canvas.setWidth(32); 

      paneCanvas.getChildren().add(canvas); 
      primaryStage.setTitle("Hello World!"); 
      primaryStage.setScene(scene); 
      primaryStage.show(); 

Answer 1

尝试这个例子...用于位置在场景的中间就可以计算出宽度以下公式：

layoutxcanvas =（widthscene/2） - （widthcanvas/2）

layoutycanvas =（heightscene/2） - （heightcanvas/2）

import java.awt.Graphics2D; 
import java.awt.Paint; 
import javafx.application.Application; 
import javafx.event.ActionEvent; 
import javafx.event.EventHandler; 
import javafx.scene.Scene; 
import javafx.scene.canvas.Canvas; 
import javafx.scene.control.Button; 
import javafx.scene.layout.Pane; 
import javafx.scene.layout.StackPane; 
import javafx.scene.paint.Color; 

import javafx.stage.Stage; 

public class JavaFXApplication1 extends Application { 

    @Override 
    public void start(Stage primaryStage) { 
     Pane paneCanvas = new Pane(); 

      final Canvas canvas = new Canvas(); 
      paneCanvas.setStyle("-fx-background-color: black;"); 

      canvas.setHeight(32); 
      canvas.setWidth(32); 
      canvas.getGraphicsContext2D().setFill(Color.WHITE); 
      canvas.getGraphicsContext2D().fillRect(0, 0, 32, 32); 

      canvas.setLayoutX((300/2)-(32/2)); 
      canvas.setLayoutY((300/2)-(32/2)); 

      paneCanvas.getChildren().add(canvas); 
      Scene scene=new Scene(paneCanvas,300,300); 
      primaryStage.setTitle("Hello World!"); 
      primaryStage.setScene(scene); 
      primaryStage.show(); 
    } 

    /** 
    * @param args the command line arguments 
    */ 
    public static void main(String[] args) { 
     launch(args); 
    }