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从Javafx帆布中擦除抗脉酸形状

 2023-02-15    304  

问题描述

我继承了一个模拟程序，以扩展使用新功能.原件是使用AWT库作为图形的小程序.在添加新功能之前，我想将程序调整到桌面上并使用Javafx代替AWT.

模拟每秒绘制数百或数千个对象，然后将它们擦除并在新位置重新粉刷它们，从而有效地使它们动画.我正在为UI的那部分使用帆布对象.擦除是通过用背景颜色重新粉刷对象来完成的.我看到的是擦除对象是不完整的.

从Javafx帆布中擦除抗脉酸形状

以下程序说明了问题.单击”绘制”按钮会导致它使用前景颜色在画布上绘制几百个圆圈.绘制后，再次单击按钮将通过重新绘制背景颜色来删除圆圈.绘制/擦除的多个周期将建立”幽灵”图像的可见背景.

package com.clartaq.antialiasingghosts;

import javafx.application.Application;
import javafx.application.Platform;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.*;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

import java.util.Random;

public class Main extends Application {

    static final int NUM_CIRCLES = 500;
    static final int CIRCLE_DIAMETER = 10;
    static final double PANEL_WIDTH = 75.0;
    static final double PANEL_HEIGHT = 40.0;
    static final Color FG_COLOR = Color.rgb(10, 0, 200);
    static final Color BG_COLOR = Color.rgb(255, 255, 255);
    static final double BUTTON_WIDTH = 50.0;

    GraphicsContext gc;

    Random rand = new Random();

    double[] px = new double[NUM_CIRCLES];
    double[] py = new double[NUM_CIRCLES];

    void randomizeParticlePositions() {
        for (int i = 0; i < NUM_CIRCLES; i++) {
            px[i] = rand.nextDouble() * PANEL_WIDTH;
            py[i] = rand.nextDouble() * PANEL_HEIGHT;
        }
    }

    void drawCircles(Color color) {
        gc.setFill(color);
        for (int i = 0; i < NUM_CIRCLES; i++) {
            var screenX = px[i] * CIRCLE_DIAMETER;
            var screenY = py[i] * CIRCLE_DIAMETER;
            gc.fillOval(screenX, screenY, CIRCLE_DIAMETER, CIRCLE_DIAMETER);
        }
    }

    @Override
    public void start(Stage stage) {
        String javaVersion   = System.getProperty("java.version");
        String javafxVersion = System.getProperty("javafx.version");

        stage.setTitle("AntiAliasingGhosts -- erasing objects leaves ghosts in JavaFX");

        Label versionLabel = new Label("JavaFX " + javafxVersion
                + ", running on Java " + javaVersion + ".");

        double canvasWidth  = (PANEL_WIDTH * CIRCLE_DIAMETER);
        double canvasHeight = (PANEL_HEIGHT * CIRCLE_DIAMETER);
        Canvas canvasRef    = new Canvas(canvasWidth, canvasHeight);
        gc = canvasRef.getGraphicsContext2D();

        Button deBtn = new Button("Draw");
        deBtn.setPrefWidth(BUTTON_WIDTH);
        deBtn.setOnAction(e -> {
            String txt = deBtn.getText();
            switch (txt) {
                case "Draw" -> {
                    randomizeParticlePositions();
                    drawCircles(FG_COLOR);
                    deBtn.setText("Erase");
                }
                case "Erase" -> {
                    drawCircles(BG_COLOR);
                    deBtn.setText("Draw");
                }
                default -> Platform.exit();
            }
        });

        Button exBtn = new Button("Exit");
        exBtn.setPrefWidth(BUTTON_WIDTH);
        exBtn.setOnAction(e -> Platform.exit());

        TilePane tp = new TilePane();
        tp.setAlignment(Pos.CENTER);
        tp.setHgap(10);
        tp.getChildren().addAll(deBtn, exBtn);

        VBox root = new VBox();
        root.setPadding(new Insets(7));
        root.setSpacing(10);
        root.setAlignment(Pos.CENTER);
        root.getChildren().addAll(versionLabel, canvasRef, tp);

        StackPane      sp = new StackPane(root);
        BackgroundFill bf = new BackgroundFill(BG_COLOR, CornerRadii.EMPTY, Insets.EMPTY);
        Background     bg = new Background(bf);
        sp.setBackground(bg);

        Scene scene = new Scene(sp, 640.0, 480.0);

        stage.setScene(scene);
        stage.show();
    }

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

}

我可以通过在擦除时将圆的直径扩大2像素来获得良好的擦除.当然，这也可能影响附近的形状.

另外，使用填充方法擦除整个画布似乎是合理的，但这意味着如果必须重新划定任何内容，则必须重新划定所有内容.我想可以通过擦除和绘制画布的较小部分来优化重新绘制，但如果不需要，我不想这样做.

程序显示屏的放大部分表明它确实是一种抗脉化效果.使用SceneAntialIasing.disabled参数构建场景似乎没有任何效果.

尝试关闭图像平滑，如 没有帮助.

可以通过在背景颜色中重新绘制在画布上绘制的单一形状?

我使用的是Java 17.0.1，Javafx 17.0.1，如果相关，则使用5K Mac显示.

推荐答案

For expedience, note the difference between fillOval and strokeOval() in the GraphicsContext .您可以在drawCircles()中有条件删除大纲，作为合适的布尔值的函数:

if (stroke) {
    gc.setStroke(BG_COLOR);
    gc.strokeOval(screenX, screenY, CIRCLE_DIAMETER, CIRCLE_DIAMETER);
}

尝试一些代表性的形状，例如fillRect，以验证所需的结果.

更好的选择，IMO，是追求> render 策略.完整的示例可以看到在这里Noreferrer”>此处可以帮助您确定该方法是否可扩展到您的用例.另请参见此相关的 recampling fors.

检查

正式方法，如测试:

import javafx.application.Application;
import javafx.application.Platform;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.*;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

import java.util.Random;

public class Main extends Application {

    static final int NUM_CIRCLES = 500;
    static final int CIRCLE_DIAMETER = 10;
    static final double PANEL_WIDTH = 75.0;
    static final double PANEL_HEIGHT = 40.0;
    static final Color FG_COLOR = Color.rgb(10, 0, 200);
    static final Color BG_COLOR = Color.rgb(255, 255, 255);
    static final double BUTTON_WIDTH = 50.0;

    GraphicsContext gc;

    Random rand = new Random();
    private boolean stroke;

    double[] px = new double[NUM_CIRCLES];
    double[] py = new double[NUM_CIRCLES];

    void randomizeParticlePositions() {
        for (int i = 0; i < NUM_CIRCLES; i++) {
            px[i] = rand.nextDouble() * PANEL_WIDTH;
            py[i] = rand.nextDouble() * PANEL_HEIGHT;
        }
    }

    void drawCircles(Color color) {
        gc.setFill(color);
        for (int i = 0; i < NUM_CIRCLES; i++) {
            var screenX = px[i] * CIRCLE_DIAMETER;
            var screenY = py[i] * CIRCLE_DIAMETER;
            gc.fillOval(screenX, screenY, CIRCLE_DIAMETER, CIRCLE_DIAMETER);
            if (stroke) {
                gc.setStroke(BG_COLOR);
                gc.strokeOval(screenX, screenY, CIRCLE_DIAMETER, CIRCLE_DIAMETER);
            }
        }
    }

    @Override
    public void start(Stage stage) {
        String javaVersion = System.getProperty("java.version");
        String javafxVersion = System.getProperty("javafx.version");

        stage.setTitle("AntiAliasingGhosts -- erasing objects leaves ghosts in JavaFX");

        Label versionLabel = new Label("JavaFX " + javafxVersion
            + ", running on Java " + javaVersion + ".");

        double canvasWidth = (PANEL_WIDTH * CIRCLE_DIAMETER);
        double canvasHeight = (PANEL_HEIGHT * CIRCLE_DIAMETER);
        Canvas canvasRef = new Canvas(canvasWidth, canvasHeight);
        gc = canvasRef.getGraphicsContext2D();

        Button deBtn = new Button("Draw");
        deBtn.setPrefWidth(BUTTON_WIDTH);
        deBtn.setOnAction(e -> {
            String txt = deBtn.getText();
            switch (txt) {
                case "Draw" -> {
                    randomizeParticlePositions();
                    drawCircles(FG_COLOR);
                    deBtn.setText("Erase");
                    stroke = true;
                }
                case "Erase" -> {
                    drawCircles(BG_COLOR);
                    deBtn.setText("Draw");
                    stroke = false;
                }
                default ->
                    Platform.exit();
            }
        });

        Button exBtn = new Button("Exit");
        exBtn.setPrefWidth(BUTTON_WIDTH);
        exBtn.setOnAction(e -> Platform.exit());

        TilePane tp = new TilePane();
        tp.setAlignment(Pos.CENTER);
        tp.setHgap(10);
        tp.getChildren().addAll(deBtn, exBtn);

        VBox root = new VBox();
        root.setPadding(new Insets(7));
        root.setSpacing(10);
        root.setAlignment(Pos.CENTER);
        root.getChildren().addAll(versionLabel, canvasRef, tp);

        StackPane sp = new StackPane(root);
        BackgroundFill bf = new BackgroundFill(BG_COLOR, CornerRadii.EMPTY, Insets.EMPTY);
        Background bg = new Background(bf);
        sp.setBackground(bg);

        Scene scene = new Scene(sp, 640.0, 480.0);

        stage.setScene(scene);
        stage.show();
    }

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

}

以上所述是小编给大家介绍的从Javafx帆布中擦除抗脉酸形状,希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对77isp云服务器技术网的支持！

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