Swing實現canvas-nest.js 原始碼

摘要： #### 說明 canvas-nest.js 原始碼 http://www.bubuko.com/infodetail-2237716.html 地址：https://gitee.com/dgwcode/MyJavaCode/tree/master/Canvas-nest-swin...

#### 說明

canvas-nest.js 原始碼

http://www.bubuko.com/infodetail-2237716.html

地址：https://gitee.com/dgwcode/MyJavaCode/tree/master/Canvas-nest-swing

實現過程

1. 繪製一個容器

2. 用隨機數生成座標，繪製100個點

3. 用隨機數生成每個點的運動方向，每次x軸位移多少，y軸位移多少

4. 每1/60秒用for迴圈重新計算點的座標，重繪畫布

5. 兩個for迴圈巢狀，判斷每個點與其他點的距離，若小於90px，則繪製連線，且連線的rgba透明度根據距離而變化6.新增滑鼠吸附事件，滑鼠進入畫布後實時監聽其位置，並在上述for迴圈中判斷與滑鼠的距離，設點為r，距離為dist，若dist>70且dist<140，rx-=0.03xdist，r.y-=0.03y_dist，即可實現吸附效果（前半段為加速，後半段為吸附）

Code

package main.canvas;

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

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

import java.awt.BorderLayout;
import java.awt.Color;

public class MainFrame extends JFrame {

private static final long serialVersionUID = -8808883923263763897L;
private static volatile MainFrame instance;

public MainFrame() {

this.setTitle("Canvas Nest");
this.setSize(new Dimension(660, 470));
this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
this.setLocation((Toolkit.getDefaultToolkit().getScreenSize().width - this.getWidth()) / 2,
(Toolkit.getDefaultToolkit().getScreenSize().height - this.getHeight()) / 2);
this.setMinimumSize(new Dimension(400, 300));
this.setResizable(true);
this.setVisible(true);
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});

/**
* 100個點位置與方向的初始化
*/
R[] r = new R[100];
M mousePoint = new M();//監聽滑鼠位置
for (int i = 0; i < r.length; i++) {
r[i] = new R();
r[i].x = (float) (Math.random() * 660);
r[i].y = (float) (Math.random() * 470);
r[i].xa = (float) (2 * Math.random() - 1);//方向
r[i].ya = (float) (2 * Math.random() - 1);//方向
}

JPanel panel = new JPanel() {
private static final long serialVersionUID = -7507627235240618009L;

@Override
public void paint(Graphics g1) {
Graphics2D g_point = (Graphics2D) g1;//點
Graphics2D g_line = (Graphics2D) g1;//線
g_point.setColor(Color.blue);
// 通過鍵值設定渲染的抗鋸齒
g_line.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g_point.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
super.paint(g_point);
super.paint(g_line);

for (int i = 0; i < r.length; i++) {
for (int j = 0; j < r.length; j++) {
// 畫點 實際上可用filloval實現
g_point.drawLine((int) r[i].x, (int) r[i].y, (int) r[i].x, (int) r[i].y);
if (r[i] != r[j]) {
// 得到兩個不同點的座標 構成算出第三條邊的長度dist
float x_dist = r[i].x - r[j].x;
float y_dist = r[i].y - r[j].y;
float dist = (float) (x_dist * x_dist + y_dist * y_dist);
// 根據距離算出透明度
float a = 0;
if (dist > 0 && dist < 8100) {
a = (1 - (dist / 8100)) * 100;
g_line.setColor(new Color(0, 100, 150, (int) a));
g_line.drawLine((int) r[i].x, (int) r[i].y, (int) r[j].x, (int) r[j].y);
}
}
}
}
}
};
panel.setBackground(Color.WHITE);
getContentPane().add(panel, BorderLayout.CENTER);

/**
* 滑鼠事件處理程式碼
*/
panel.addMouseMotionListener(new MouseMotionAdapter() {
@Override
public void mouseMoved(MouseEvent e) {
mousePoint.x = (float) e.getX();
mousePoint.y = (float) e.getY();
}
});

panel.addMouseListener(new MouseAdapter() {
@Override
public void mouseExited(MouseEvent e) {
mousePoint.x = null;
mousePoint.y = null;
}
});

new Thread(new Runnable() {

@Override
public void run() {
while (true) {
try {
for (int i = 0; i < r.length; i++) {
// 僅僅加上方向值
r[i].x += r[i].xa;
r[i].y += r[i].ya;
/**
* 當前隨機點如果在可視view中 那麼
*/
r[i].xa *= r[i].x > 660 || r[i].x < 0 ? -1 : 1;
r[i].ya *= r[i].y > 470 || r[i].y < 0 ? -1 : 1;
// 在視窗的可視大小環境中
if (mousePoint.x != null && mousePoint.y != null) {
float x_dist = r[i].x - mousePoint.x;
float y_dist = r[i].y - mousePoint.y;
float dist = (float) (x_dist * x_dist + y_dist * y_dist);
if (dist > 4900 && dist < 19600) {
r[i].x -= 0.03 * x_dist;
r[i].y -= 0.03 * y_dist;
}
}
}
/**
* 4.每1/60秒用for迴圈重新計算點的座標，重繪畫布
* 5.兩個for迴圈巢狀，判斷每個點與其他點的距離，
* 若小於90px，則繪製連線，且連線的rgba透明度根據距離而變化
*/
panel.repaint();
Thread.sleep(1000 / 60);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}).start();

}

public static MainFrame getIstance() {
if (instance == null) {
synchronized (MainFrame.class) {
if (instance == null) {
instance = new MainFrame();
}
}
}
return instance;
}

private class R {

float x;
float y;
float xa;
float ya;

}

private class M {
Float x;
Float y;
}

}