本文介绍了如何在Java中平滑滚动JFrame的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我的Java应用程序中有一个JFrame，其中包含 JPanel ，其中我在运行时创建了一些绘图对象。问题是滚动 JFrame 为大数字滚动减慢并且滚动条不能平滑移动。请注意我正在使用 Graphics 2D 对象并在滚动操作上执行重绘。
I have a JFrame in my Java application that contains a JPanel where I have some drawing objects created at run-time. The problem is while scrolling the JFrame for large figures the scrolling slows up and scroll bar does not move smoothly. Please note I am using Graphics 2D object and doing repaint on scroll action.
有没有办法平滑 JFrame 的滚动动作。
Is there any way of smoothing the scrolling action of JFrame.
以下是代码的一部分
public class DiagramPanel implements MouseListener{
int click=0;
Point p1;
Point p2;
private Dimension panelDimension;
.... // variables
public void go() {
p1 = new Point();
p2 = new Point();
JFrame f = new JFrame();
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.setSize(1200,500);
panelx = new DiaPanel();
panelx.setOpaque(true);
panelx.setBackground(Color.white);
panelx.setAutoscrolls(true);
panelx.addMouseListener(this);
JScrollPane scrollPane = new JScrollPane();
// scrollPane.add(panelx);
ClassRectangle tempRect = null;
for (ClassRectangle rect : this.classRectangles) {
tempRect = rect;
}
Rectangle rect = new Rectangle();
rect.setBounds(tempRect.getW() - 100, 0, 1000,
tempLife.getEndpointY() * 500);
panelDimension = new Dimension(0,0);
for (ClassRectangle rectx : classRectangles){
panelDimension.width=rectx.getW()+300;
}
for (LifeLine life : lifeLines) {
panelDimension.height=life.getEndpointY()+300;
}
scrollPane.setViewportView(panelx);
panelx.computeVisibleRect(rect);
JScrollPane scrollPane1 = new JScrollPane(panelx);
panelx.setPreferredSize(panelDimension);
panelx.repaint();
panelx.revalidate();
p1.x=0;
p1.y=0;
p2.y=panelDimension.height;
p2.x=panelDimension.width;
f.add( scrollPane1);
scrollPane.revalidate();
f.setBackground(Color.white);
}
public DiagramPanel(ArrayList<Rectangle> classRectangles,
ArrayList<Pair> pairs, ArrayList<Line> lines,
ArrayList<Life> meth) {
// constructing obj of DrawingPanel Here
}
public class SeqDiaPanel extends JPanel {
/**
*
*/
private static final long serialVersionUID = 1L;
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d2 = (Graphics2D) g;
g2d2.setColor(Color.orange);
//grid
for (int i = 0; i < panelDimension.height; i++) {
g2d2.drawLine(0, 0 + i * 5, panelDimension.width+1000, 0 + i * 5);
}
for (int i = 0; i < panelDimension.width; i++) {
g2d2.drawLine(0 + i * 5, 0, 0 + i *5,panelDimension.height+300);
}
g2d2.setColor(Color.black);
// objects
.......... some objects here
}
}
// draw Lines
Stroke drawingStroke = new BasicStroke(2, BasicStroke.CAP_BUTT,
BasicStroke.JOIN_BEVEL, 0, new float[] { 5 }, 0);
// Stroke drawingStroke = new BasicStroke();
Graphics2D g2d = (Graphics2D) g;
g2d.setStroke(drawingStroke);
for (Line life : lines) {
g2d.drawLine(life.getStartpointX(), life.getStartpointY(),
life.getEndpointX(), life.getEndpointY());
panelDimension.height=life.getEndpointY()+300;
}
// draw methodLfe
for (Object2 ml1 : Obj2) {
g2d2.fill3DRect(ml1.StartX(), ml1.getMethodStartY(),
ml1.getBreadth(), ml1.getEndX(),true);
}
}
}
// tobeused
public int calculateWidth(String name){
Font font = new Font("Serif", Font.BOLD, 12);
FontMetrics metrics = new FontMetrics(font){
/**
*
*/
private static final long serialVersionUID = 1L;};
int tempInt2=SwingUtilities.computeStringWidth( metrics, name);
tempInt2=tempInt2+10;
return tempInt2;
}
/*public class MouseClick implements MouseListener{
Point p = new Point(0,0);
@Override
public void mouseClicked(MouseEvent evnt) {
p.x=evnt.getX();
p.y=evnt.getY();
System.out.println("MouseClicked @"+p.x+":"+p.y);
}
@Override
public void mouseEntered(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mousePressed(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseReleased(MouseEvent arg0) {
// TODO Auto-generated method stub
}
}*/
@Override
public void mouseClicked(MouseEvent evnt) {
click++;
if(click==1){
//Point p= new Point();
p1.x=evnt.getX();
p1.y=evnt.getY();
// System.out.println("MouseClicked1 @"+p1.x+":"+p1.y);
}
if(click==2){
p2.x=evnt.getX();
p2.y=evnt.getY();
//System.out.println("MouseClicked2 @"+p2.x+":"+p2.y);
click=0;
if(p1.x<p2.x&&p1.y<p2.y){
panelx.repaint();
}
else{
}
}/*else{
p1.x=0;
p1.y=0;
p2.x=panelDimension.width+500;
p2.y=panelDimension.height+700;
}*/
}
@Override
public void mouseEntered(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mousePressed(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseReleased(MouseEvent arg0) {
// TODO Auto-generated method stub
}
}
推荐答案
为什么不将 Graphics2D 绘图放入（大） BufferedImage 并将其显示在滚动窗格的标签中？像这样的东西（动画，5000x5000px）：
Why not put the Graphics2D drawing in a (large) BufferedImage and display it in a label in a scroll-pane? Something like this (animated, 5000x5000px):
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.swing.*;
public class BigScrollImage {
BigScrollImage() {
final int x = 5000;
final int y = 5000;
final BufferedImage bi = new BufferedImage(x,y,BufferedImage.TYPE_INT_RGB);
Graphics2D g1 = bi.createGraphics();
g1.setColor(Color.BLACK);
g1.fillRect(0, 0, x, y);
g1.dispose();
final JLabel label = new JLabel(new ImageIcon(bi));
ActionListener listener = new ActionListener() {
Random rand = new Random();
@Override
public void actionPerformed(ActionEvent ae) {
Graphics2D g2 = bi.createGraphics();
int x1 = rand.nextInt(x);
int x2 = rand.nextInt(x);
int y1 = rand.nextInt(y);
int y2 = rand.nextInt(y);
int r = rand.nextInt(255);
int g = rand.nextInt(255);
int b = rand.nextInt(255);
g2.setColor(new Color(r,g,b));
g2.drawLine(x1,y1,x2,y2);
g2.dispose();
label.repaint();
}
};
Timer t = new Timer(5,listener);
JScrollPane scroll = new JScrollPane(label);
JFrame f = new JFrame("Big Scroll");
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.add(scroll);
f.pack();
f.setSize(800, 600);
f.setLocationByPlatform(true);
f.setVisible(true);
t.start();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
@Override
public void run() {
new BigScrollImage();
}
});
}
}
它试图每秒绘制200行，并且似乎在这里顺利滚动。
It tries to draw 200 hundred lines per second, and seems to scroll smoothly here.
这篇关于如何在Java中平滑滚动JFrame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！