如何在javaFX中制作canvas Resizable？ [英] How to make canvas Resizable in javaFX?

问题描述

在javaFX中调整画布大小没有这样的方法，唯一的解决方案是从Canvas扩展。

In javaFX to resize a canvas there is no such method to do that, the only solution is to extends from Canvas.

class ResizableCanvas extends Canvas {

    public ResizableCanvas() {
        // Redraw canvas when size changes.
        widthProperty().addListener(evt -> draw());
        heightProperty().addListener(evt -> draw());
    }

    private void draw() {
        double width = getWidth();
        double height = getHeight();

        GraphicsContext gc = getGraphicsContext2D();
        gc.clearRect(0, 0, width, height);

    }

    @Override
    public boolean isResizable() {
        return true;
    }
}

从Canvas扩展是制作画布的唯一解决方案可调整大小？
，因为这个解决方案只有在我们不想使用FXML时才有效，如果我们在fxml中声明一个画布我们怎样才能使它可以调整大小？

is extends from Canvas is the only solution to make canvas Resizable ? because this solution work only if we don't want to use FXML, if we declare in fxml a canvas how can we make it resizable?

这是我的代码：

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.layout.AnchorPane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class Main extends Application {

    Controller controller;

    @Override
    public void start(Stage primaryStage) throws Exception{
        FXMLLoader loader = new FXMLLoader(getClass().getResource("sample.fxml"));
        AnchorPane root = loader.load(); // controller initialized
        controller = loader.getController();
        GraphicsContext gc = controller.canvas.getGraphicsContext2D();
        gc.setFill(Color.AQUA);
        gc.fillRect(0, 0, root.getPrefWidth(), root.getPrefHeight());
        primaryStage.setTitle("Hello World");
        primaryStage.setScene(new Scene(controller.Pane, controller.Pane.getPrefWidth(), controller.Pane.getPrefHeight()));
        primaryStage.show();
    }

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

推荐答案

这里有我认为你可以找到一个有用的设置可调整大小的画布的指南：

There's a guide that I think that you may find useful for setting up a resizable canvas:

JavaFx提示 - 可调整大小的画布

指南中的一段代码：

Piece of code from the guide:

/**
 * Tip 1: A canvas resizing itself to the size of
 *        the parent pane.
 */
public class Tip1ResizableCanvas extends Application {

    class ResizableCanvas extends Canvas {

        public ResizableCanvas() {
            // Redraw canvas when size changes.
            widthProperty().addListener(evt -> draw());
            heightProperty().addListener(evt -> draw());
        }

        private void draw() {
            double width = getWidth();
            double height = getHeight();

            GraphicsContext gc = getGraphicsContext2D();
            gc.clearRect(0, 0, width, height);

            gc.setStroke(Color.RED);
            gc.strokeLine(0, 0, width, height);
            gc.strokeLine(0, height, width, 0);
        }

        @Override
        public boolean isResizable() {
            return true;
        }

        @Override
        public double prefWidth(double height) {
            return getWidth();
        }

        @Override
        public double prefHeight(double width) {
            return getHeight();
        }
    }

这篇关于如何在javaFX中制作canvas Resizable？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！