如何在内存中吧图片一副画到另一副图片上。

[jspxnet]

一个是背景图A，
一个是前图：B
A + B ＝ ？？？如何着。 最好是 CODE

[z_yheart]

下面是一个图象合成的例子，希望对你会有帮助

/*
* @(#)Composite.java 1.2 98/07/31
*/

import java.lang.Integer;
import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.awt.image.*;

import java.awt.event.ItemListener;
import java.awt.event.ItemEvent;
import javax.swing.*;

/*
* This applet renders an ellipse overlapping a rectangle with the compositing rule and
* alpha value selected by the user.
*/

public class Composite extends JApplet implements ItemListener {
CompPanel comp;
JLabel alphaLabel, rulesLabel;
JComboBox alphas, rules;
String alpha = "1.0";
int rule = 0;

// Initializes the layout of the components.
public void init() {
GridBagLayout layOut = new GridBagLayout();
getContentPane().setLayout(layOut);

GridBagConstraints l = new GridBagConstraints();
l.weightx = 1.0;
l.fill = GridBagConstraints.BOTH;
l.gridwidth = GridBagConstraints.RELATIVE;
alphaLabel = new JLabel();
alphaLabel.setText("Alphas");
Font newFont = getFont().deriveFont(1);
alphaLabel.setFont(newFont);
alphaLabel.setHorizontalAlignment(JLabel.CENTER);
layOut.setConstraints(alphaLabel, l);
getContentPane().add(alphaLabel);
GridBagConstraints c = new GridBagConstraints();
getContentPane().setLayout(layOut);

l.gridwidth = GridBagConstraints.REMAINDER;
rulesLabel = new JLabel();
rulesLabel.setText("Rules");
newFont = getFont().deriveFont(1);
rulesLabel.setFont(newFont);
rulesLabel.setHorizontalAlignment(JLabel.CENTER);
layOut.setConstraints(rulesLabel, l);
getContentPane().add(rulesLabel);

GridBagConstraints a = new GridBagConstraints();
a.gridwidth = GridBagConstraints.RELATIVE;
a.weightx = 1.0;
a.fill = GridBagConstraints.BOTH;
alphas = new JComboBox();
layOut.setConstraints(alphas, a);
alphas.addItem("1.0");
alphas.addItem("0.75");
alphas.addItem("0.50");
alphas.addItem("0.25");
alphas.addItem("0.0");
alphas.addItemListener(this);
getContentPane().add(alphas);

a.gridwidth = GridBagConstraints.REMAINDER;
rules = new JComboBox();
layOut.setConstraints(rules, a);
rules.addItem("SRC");
rules.addItem("DST_IN");
rules.addItem("DST_OUT");
rules.addItem("DST_OVER");
rules.addItem("SRC_IN");
rules.addItem("SRC_OVER");
rules.addItem("SRC_OUT");
rules.addItem("CLEAR");
rules.addItemListener(this);
getContentPane().add(rules);

GridBagConstraints fC = new GridBagConstraints();
fC.fill = GridBagConstraints.BOTH;
fC.weightx = 1.0;
fC.weighty = 1.0;
fC.gridwidth = GridBagConstraints.REMAINDER;
comp = new CompPanel();
layOut.setConstraints(comp, fC);
getContentPane().add(comp);

validate();
}

/*
* Detects a change in either of the Choice components. Resets the variable corresponding
* to the Choice whose state is changed. Invokes changeRule in CompPanel with the current
* alpha and composite rules.
*/
public void itemStateChanged(ItemEvent e){
if ( e.getStateChange() != ItemEvent.SELECTED ) {
return;
}

Object choice = e.getSource();
if ( choice == alphas ) {
alpha = (String)alphas.getSelectedItem();
} else {
rule = rules.getSelectedIndex();
}
comp.changeRule(alpha, rule);
}

public static void main(String s[]) {
JFrame f = new JFrame("Composite");
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {System.exit(0);}
});
JApplet applet = new Composite();
f.getContentPane().add("Center", applet);
applet.init();
f.pack();
f.setSize(new Dimension(300,300));
f.show();
}
}


class CompPanel extends JPanel {

AlphaComposite ac = AlphaComposite.getInstance(AlphaComposite.SRC);
float alpha = 1.0f;

public CompPanel(){}

// Resets the alpha and composite rules with selected items.
public void changeRule(String a, int rule) {
alpha = Float.valueOf(a).floatValue();
ac = AlphaComposite.getInstance(getRule(rule), alpha);
repaint();
}

// Gets the requested compositing rule.
public int getRule(int rule){
int alphaComp = 0;
switch ( rule ) {
case 0: alphaComp = AlphaComposite.SRC; break;
case 1: alphaComp = AlphaComposite.DST_IN; break;
case 2: alphaComp = AlphaComposite.DST_OUT; break;
case 3: alphaComp = AlphaComposite.DST_OVER; break;
case 4: alphaComp = AlphaComposite.SRC_IN; break;
case 5: alphaComp = AlphaComposite.SRC_OVER; break;
case 6: alphaComp = AlphaComposite.SRC_OUT; break;
case 7: alphaComp = AlphaComposite.CLEAR; break;
}
return alphaComp;
}

public void paintComponent(Graphics g) {
super.paintComponent( g );
Graphics2D g2 = (Graphics2D) g;

Dimension d = getSize();
int w = d.width;
int h = d.height;

// Creates the buffered image.
BufferedImage buffImg = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
Graphics2D gbi = buffImg.createGraphics();

// Clears the previously drawn image.
g2.setColor(Color.white);
g2.fillRect(0, 0, d.width, d.height);

int rectx = w/4;
int recty = h/4;

// Draws the rectangle and ellipse into the buffered image.
gbi.setColor(new Color(0.0f, 0.0f, 1.0f, 1.0f));
gbi.fill(new Rectangle2D.Double(rectx, recty, 150, 100));
gbi.setColor(new Color(1.0f, 0.0f, 0.0f, 1.0f));
gbi.setComposite(ac);
gbi.fill(new Ellipse2D.Double(rectx+rectx/2,recty+recty/2,150,100));

// Draws the buffered image.
g2.drawImage(buffImg, null, 0, 0);
}
}

[z_yheart]

是从http://java.sun.com/docs/books/tutorial/2d/display/compositing.html载的，你也可以去看看

[jspxnet]

在内存中吧一副图片画到另一副图片上。

还有人吗？

[Patrick_DK]

紧急插播:

小弟将另外高分重谢

http://www.csdn.net/expert/topic/474/474558.shtm

http://www.csdn.net/expert/topic/474/474509.shtm

http://www.csdn.net/expert/topic/474/474544.shtm

[z_yheart]

不是一样的吗？你只要得到两个Image对象不就可以那样操作了吗？

[jspxnet]

谢谢了

[jspxnet]

看了它，我明白了一半，还差一半。
这个东西 paintComponent 在 JApplet 有
Applet中不知道有没有。
应该10句之内就能搞定的吧。

[z_yheart]

Applet中也有