使用paintComponent的Java幻灯片图像延迟 [英] Java slideshow image delay using paintComponent
问题描述
我正在整理一个幻灯片显示程序，该程序将测量用户在每张幻灯片上花费的时间.幻灯片显示了几种不同的魔术.每个技巧显示两次.在重复之间显示了临时图像.在每个技巧之间显示过渡图像.
I am putting together a slideshow program that will measure a user's time spent on each slide. The slideshow goes through several different magic tricks. Each trick is shown twice. Interim images are shown between the repetition. Transition images are shown between each trick.
在第一次重复播放花样时，单击JPanel颜色会在屏幕上闪烁，然后显示下一张图像.在相同技巧的第二次重复过程中不会发生这种情况.图片加载时间过长.
On the first repetition of a trick the JPanel color flashes on the screen after a click before the next image is shown. This doesn't happen during the second repetition of the same trick. It's possible that the image is taking too long to load.
是否有一种简单的方法来预加载图像，以使第一次使用时没有延迟?
Is there an easy way to pre-load the images so that there isn't a delay the first time through?
NOTE: Original code deleted.
编辑1/10/2013:现在，此代码可在速度较慢的计算机上使用.废纸go的第二个附录最大的帮助. mouseClick控件结构会定期要求SwingWorker类加载40个或更少的当前技巧图像，同时还将使用的图像设置为null.为此，我已将代码简化为仅两个Image []，并添加了main方法，使其独立存在.图像仍然需要运行.现在，这是非常简单的代码，如果您要制作包含很多图像的幻灯片，我认为这是一个不错的起点.
EDIT 1/10/2013: This code now works on slower machines. trashgod's second addendum helped the most. The mouseClick control structure periodically asks SwingWorker classes to load 40 images or less of the current trick while also setting the used images to null. I have simplified my code down for this to just two Image[]s and added a main method so it stands alone. Images are still required to run though. This is now pretty bare bones code, and if you're trying to make a slideshow with a lot of images I think it would be a good place to start.
注意:我想我想出了如何在仍然使用多个Image []的情况下正确实现SwingWorker的方法.垃圾桶和kleopatra的实现是否符合您的建议?我最终没有使用发布和处理，因为我无法弄清楚如何使它与索引数组一起正常工作，而是因为StringWorker不会加载数组中的所有图像(仅加载40个)，并且代码每20张图片调用一次StringWorker，应该有一个不错的缓冲区.
NOTE: I think I figured out how to properly implement SwingWorker while still using multiple Image[]s. trashgod and kleopatra is this implementation in-line with what you were suggesting? I didn't end up using publish and process since I couldn't figure out how to get that to work appropriately with an indexed array, but because the StringWorker doesn't load all images in the array (only 40), and the code calls StringWorker every 20 images, there should be a pretty good buffer.
编辑2013年1月10日，改为通过在我的Mouse类上扩展MouseAdapter来更改MouseListener.还修复了我的paintComponent方法，以包括对super.paintComponent(g)的调用. 在我的SwingWorker类ImageWorker中添加了发布/处理方法.添加了一个包装器类ArrayWrapper，以允许将imageArray [i]及其对应的索引int i传递给发布进行处理.
EDIT 1/10/2013 Changed out MouseListener by instead extending MouseAdapter on my Mouse class. Also fixed my paintComponent method to include a call to super.paintComponent(g). Added publish/process methods to my SwingWorker class ImageWorker. Added a wrapper class, ArrayWrapper to allow passing imageArray[i] and its corresponding index int i with publish to process.
package slideshow3;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.MouseEvent;
import java.awt.event.MouseAdapter;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import java.util.List;
public class SlideShow3 extends JFrame
{
//screenImage will be replaced with each new slide
private Image screenImage;
private int width;
private int height;
//Create panel for displaying images using paintComponent()
private SlideShow3.PaintPanel mainImagePanel;
//Used for keybinding
private Action escapeAction;
//Image array variables for each trick
private Image[] handCuffs; //h
private Image[] cups; //c
//Used to step through the trick arrays one image at a time
private int h = 0;
private int c = 0;
//Used by timeStamp() for documenting time per slide
private long time0 = 0;
private long time1;
public SlideShow3()
{
super();
//Create instance of each Image array
handCuffs = new Image[50];
cups = new Image[176];
//start(handCuffsString);
start("handCuffs");
try
{
screenImage = ImageIO.read(new File("images/begin1.jpg"));
}
catch (IOException nm)
{
System.out.println("begin");
System.out.println(nm.getMessage());
System.exit(0);
}
/******************************************
* Removes window framing. The next line sets fullscreen mode.
* Once fullscreen is set width and height are determined for the window
******************************************/
this.setUndecorated(true);
GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().setFullScreenWindow(this);
width = this.getWidth();
height = this.getHeight();
//Mouse click binding to slide advance control structure
addMouseListener(new Mouse());
//Create panel so that I can use key binding which requires JComponent
mainImagePanel = new PaintPanel();
add(mainImagePanel);
/******************************************
* Key Binding
* ESC will exit the slideshow
******************************************/
// Key bound AbstractAction items
escapeAction = new EscapeAction();
// Gets the mainImagePanel InputMap and pairs the key to the action
mainImagePanel.getInputMap().put(KeyStroke.getKeyStroke("ESCAPE"), "doEscapeAction");
// This line pairs the AbstractAction enterAction to the action "doEnterAction"
mainImagePanel.getActionMap().put("doEscapeAction", escapeAction);
/******************************************
* End Key Binding
******************************************/
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run()
{
SlideShow3 show = new SlideShow3();
show.setVisible(true);
}
});
}
//This method executes a specific SwingWorker class to preload images
public void start(String e)
{
if(e.equals("handCuffs"))
{
new ImageWorker(handCuffs.length, h, e).execute();
}
else if(e.equals("cups"))
{
new ImageWorker(cups.length, c, e).execute();
}
}
//Stretches and displays images in fullscreen window
private class PaintPanel extends JPanel
{
@Override
public void paintComponent(Graphics g)
{
if(screenImage != null)
{
super.paintComponent(g);
g.drawImage(screenImage, 0, 0, width, height, this);
}
}
}
/******************************************
* The following SwingWorker class Pre-loads all necessary images.
******************************************/
private class ArrayWrapper
{
private int i;
private Image image;
public ArrayWrapper(Image image, int i)
{
this.i = i;
this.image = image;
}
public int getIndex()
{
return i;
}
public Image getImage()
{
return image;
}
}
private class ImageWorker extends SwingWorker<Image[], ArrayWrapper>
{
private int currentPosition;
private int arraySize;
private String trickName;
private Image[] imageArray;
public ImageWorker(int arraySize, int currentPosition, String trick)
{
super();
this.currentPosition = currentPosition;
this.arraySize = arraySize;
this.trickName = trick;
}
@Override
public Image[] doInBackground()
{
imageArray = new Image[arraySize];
for(int i = currentPosition; i < currentPosition+40 && i < arraySize; i++)
{
try
{
imageArray[i] = ImageIO.read(new File("images/" + trickName + (i+1) + ".jpg"));
ArrayWrapper wrapArray = new ArrayWrapper(imageArray[i], i);
publish(wrapArray);
}
catch (IOException e)
{
System.out.println(trickName);
System.out.println(e.getMessage());
System.exit(0);
}
}
return imageArray;
}
@Override
public void process(List<ArrayWrapper> chunks)
{
for(ArrayWrapper element: chunks)
{
if(trickName.equals("handCuffs"))
{
handCuffs[element.getIndex()] = element.getImage();
}
else if(trickName.equals("cups"))
{
cups[element.getIndex()] = element.getImage();
}
}
}
@Override
public void done()
{
try
{
if(trickName.equals("handCuffs"))
{
handCuffs = get();
}
else if(trickName.equals("cups"))
{
cups = get();
}
}
catch(InterruptedException ignore){}
catch(java.util.concurrent.ExecutionException e)
{
String why = null;
Throwable cause = e.getCause();
if(cause != null)
{
why = cause.getMessage();
}
else
{
why = e.getMessage();
}
System.err.println("Error retrieving file: " + why);
}
}
}
/******************************************
* End SwingWorker Pre-Loading Classes
******************************************/
//Prints out time spent on each slide
public void timeStamp()
{
time1 = System.currentTimeMillis();
if(time0 != 0)
{
System.out.println(time1 - time0);
}
time0 = System.currentTimeMillis();
}
/******************************************
* User Input Classes for Key Binding Actions and Mouse Click Actions
******************************************/
private class EscapeAction extends AbstractAction
{
@Override
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
}
public class Mouse extends MouseAdapter
{
@Override
public void mouseClicked(MouseEvent e)
{
if(!(h<handCuffs.length) && !(c<cups.length))
{
timeStamp();
System.exit(0);
}
else if(h<handCuffs.length)
{
timeStamp();
screenImage = handCuffs[h];
repaint();
System.out.print("handCuffs[" + (h+1) + "]\t");
h++;
//purge used slides and refresh slide buffer
if(h == 20 || h == 40)
{
for(int i = 0; i < h; i++)
{
handCuffs[i] = null;
}
start("handCuffs");
}
if(h == 45)
{
start("cups");
}
}
else if(c<cups.length)
{
timeStamp();
screenImage = cups[c];
repaint();
System.out.print("cups[" + (c+1) + "]\t");
c++;
//purge used slides and refresh slide buffer
if(c == 20 || c == 40 || c == 60 || c == 80 || c == 100 || c == 120 || c == 140 || c == 160)
{
for(int i = 0; i < c; i++)
{
cups[i] = null;
}
start("cups");
}
}
}
}
/******************************************
* End User Input Classes for Key Binding Actions and Mouse Click Actions
******************************************/
}
推荐答案
此示例将List<ImageIcon>用作getImage()返回的图像的cache.使用getResource()，延迟是不明显的.默认情况下，下一个和上一个按钮绑定到 Space 键.
This example uses a List<ImageIcon> as a cache of images returned by getImage(). Using getResource(), the delay is imperceptible. The next and previous buttons are bound to the Space key by default.
附录:对于示例javax.swing.Timer实例通过调节按钮的setEnabled()状态来控制导航. >.
Addendum: You can control navigation by conditioning a button's setEnabled() state using an instance of javax.swing.Timer, for example.
附录:您的第二个示例一直等到单击鼠标以开始读取图像时，这个不确定的过程可能会立即返回副本，或者直到之后 repaint().取而代之的是，使用ImageIO.read()开始读取背景中的图像，如此处所示.您可以process() List<Image>并显示进度，如此处所示.可以从初始线程启动SwingWorker，随后在EDT上构建GUI时运行.您可以在处理完第一张图像后立即显示它.
Addendum: Your second example waits until the mouse is clicked to begin reading an image, an indeterminate process that may return a copy immediately or may not complete until after repaint(). Instead, begin reading the images in the background using ImageIO.read(), as shown here. You can process() your List<Image> and show progress, as seen here. The SwingWorker can be launched from the initial thread, running while you subsequently build your GUI on the EDT. You can display the first image as soon as it is processed.
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