如何在 Java 中直接渲染屏幕？ JPanel 在 JScrollPane 内渲染

Question

大家好吗？如何在 Java 中直接在屏幕上渲染？我记得使用 setPixel 或 setRGB 来做到这一点，但是有一种方法可以设置主 JFrame 的像素并设置 ZOrder 甚至在 MS-Windows 组件之前。

这是代码和一个 *.ZIP 文件：

Mapa.java:

package com.primedi.ig;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.HeadlessException;
import java.util.Timer;
import java.util.TimerTask;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

import com.primedi.matlog.C32;
import com.primedi.tech.Arquivo;

public class Mapa extends JFrame {

    private static final long serialVersionUID = 1L;
    public String nomeMapa = null;
    private JPanel panMapa;
    private JScrollPane brPanMapa;

    public static Arquivo arqMapa = null;

    Render r = null;
    public Mapa(String nomeMapa){
        this.nomeMapa = nomeMapa;

        inicializarJanela();

        try {
            r = new Render();
            r.setBounds(658, 10, 640, 480);
        } catch (HeadlessException e) {
            e.printStackTrace();
        }

        getContentPane().add(r);
        setVisible(true);
        processosCons();
    }
    private void criarJanela(){
        //setTitle("zMeck - Início");
        setSize(1352, 594);
        getContentPane().setLayout(null);
        setResizable(false);
        setLocationRelativeTo(null);
        setUndecorated(true);
        getContentPane().setBackground(Color.BLACK);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }
    private void criarPaineis(){
        panMapa = new JPanel();
        panMapa.setLayout(null);
        panMapa.setBackground(Color.BLACK);
    }
    private void criarBarrasDeRolagem(){
        brPanMapa = new JScrollPane(panMapa);
        brPanMapa.setBounds(0, 0, 658, 498);
        brPanMapa.getHorizontalScrollBar().setUnitIncrement(32);
        brPanMapa.getVerticalScrollBar().setUnitIncrement(32);

        arqMapa = new Arquivo("mapas", "teste.pmp");
        arqMapa.carregarArquivo();
        Dimension d = new Dimension((arqMapa.linhas.get(0).length() * 32), arqMapa.linhas.size() * 32);
        panMapa.setPreferredSize(d);
    }
    private void adicionarComponentes(){
        getContentPane().add(brPanMapa);
    }
    private void inicializarJanela(){
        criarJanela();
        criarPaineis();
        criarBarrasDeRolagem();
        adicionarComponentes();
        //carregarInfosMapa();
    }
    /*private void carregarInfosMapa(){
        arqMapa = new Arquivo("mapas", nomeMapa + ".pmp");
        arqMapa.carregarArquivo();
        Dimension d = new Dimension((arqMapa.linhas.get(0).length() * 32), arqMapa.linhas.size() * 32);
        panMapa.setPreferredSize(d);
        panMapa.setVisible(true);
        for(int j = 0; j < alcanceY; j++){
            for(int i = 0; i < alcanceX; i++){
                tilesImaginarios[i][j] = new JLabel(new ImageIcon("tiles/tile0.PNG"));
                tilesImaginarios[i][j].setBounds((i * 32) + 658, j * 32, 32, 32);
                getContentPane().add(tilesImaginarios[i][j]);
            }
        }
    }*/

    public static int start = 0;
    private void processosCons(){
        Timer t = new Timer();
        t.schedule(new TimerTask() {
            int posInicialScrollX = 0;
            int posInicialScrollY = 0;

            public void run() {
                if(start == 0){
                    start = 1;
                }

                if(brPanMapa.getViewport().getViewPosition().x != posInicialScrollX){
                    posInicialScrollX = brPanMapa.getViewport().getViewPosition().x;

                    Render.OFFSET_X = C32.pixelPara32(posInicialScrollX);
                    r.repaint();
                    return;
                }

                if(brPanMapa.getViewport().getViewPosition().y != posInicialScrollY){
                    posInicialScrollY = brPanMapa.getViewport().getViewPosition().y;
                    System.out.println("hello");
                    Render.OFFSET_Y = C32.pixelPara32(posInicialScrollY);
                    r.repaint();
                    return;
                }
            }
        }, 33, 33);
    }
}

Render.java:

package com.primedi.ig;

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.HeadlessException;
import java.awt.Image;
import java.awt.Toolkit;

import javax.swing.JPanel;

import com.primedi.tech.Arquivo;

public class Render extends JPanel {
    private static final long serialVersionUID = 1L;

    public static int OFFSET_X = 0;
    public static int OFFSET_Y = 0;

    public Render() throws HeadlessException {
        super();
    }

    @Override
    protected void paintComponent(Graphics g) {
        if(Mapa.start == 1){
            Graphics2D g2d = (Graphics2D)g;

            Arquivo arq = new Arquivo("mapas", "teste.pmp");
            arq.carregarArquivo();
            for(int j = 0; j < 15; j++){
                for(int i = 0; i < 20; i++){
                    System.out.println(OFFSET_X);
                    Image img1 = Toolkit.getDefaultToolkit().getImage("tiles/tile" + "" + arq.linhas.get(j + OFFSET_Y).charAt(i + OFFSET_X) + ".PNG");
                    g2d.drawImage(img1, i * 32, j * 32, this);
                }
            }
        }
    }
}

C32.java:

package com.primedi.matlog;

public class C32 {
    public static int pixelPara32(int pixelV){
        int aprox = 0;
        int finalx = 0;
        for(aprox = 0; aprox < pixelV; aprox++);
        for(int i = 0; i < aprox; i = i + 32){
            finalx++;
        }
        return finalx;
    }
}

Arquivo.java:

package com.primedi.tech;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;

public class Arquivo {

    public ArrayList<String> linhas = new ArrayList<String>();

    public String pasta;
    public String arquivo;

    public Arquivo(String pasta, String arq){
        this.pasta = pasta;
        arquivo = arq;
    }

    public void carregarArquivo(){
        File file = new File(pasta + "/" + arquivo);

        BufferedReader br;
        try {
            br = new BufferedReader(new FileReader(file));

            String linha;
            while ((linha = br.readLine()) != null) {
                linhas.add(linha);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

当我在 JScrollBar 中插入 jpanel 方形渲染时，它是渲染过程中的错误，在图像总加载之前出现 JScrollPane 的黑色背景，荒谬。

可以帮帮我吗？非常感谢，伙计们。

这里是一个*.ZIP如果你觉得更好下载：https://expirebox.com/download/2b20ec8e44084c19d8bf1676d135d024.html

无法保留此屏幕 space 进行渲染？

错误：bug

Answer 1

看看 BufferStrategy class。

此外，除了在 paintComponent 中绘制之外，做任何事情都是一个坏主意。由于磁盘 i/o，加载图像很慢。如果可能 pre-load 它们并将它们缓存在内存中。

Answer 2

增加 "brPanMapa.getComponent(0).setVisible(false);" 在 "criarBarrasDeRolagem()"

我的代码继续快速，渲染基于 32x32 瓦片的地图速度非常快！

不知道这行代码是怎么猜出来的，5h之后！

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