下面代碼中用到的sourceImage是壹個已經存在的Image對象
圖像剪切
對於壹個已經存在的Image對象,要得到它的壹個局部圖像,可以使用下面的步驟:
//import java.awt.*;
//import java.awt.image.*;
Image croppedImage;
ImageFilter cropFilter;
CropFilter =new CropImageFilter(25,30,75,75); //四個參數分別為圖像起點坐標和寬高,即CropImageFilter(int x,int y,int width,int height),詳細情況請參考API
CroppedImage= Toolkit.getDefaultToolkit().createImage(new FilteredImageSource(sourceImage.getSource(),cropFilter));
如果是在Component的子類中使用,可以將上面的Toolkit.getDefaultToolkit().去掉。FilteredImageSource是壹個ImageProducer對象。
圖像縮放
對於壹個已經存在的Image對象,得到它的壹個縮放的Image對象可以使用Image的getScaledInstance方法:
Image scaledImage=sourceImage. getScaledInstance(100,100, Image.SCALE_DEFAULT); //得到壹個100X100的圖像
Image doubledImage=sourceImage. getScaledInstance(sourceImage.getWidth(this)*2,sourceImage.getHeight(this)*2, Image.SCALE_DEFAULT); //得到壹個放大兩倍的圖像,這個程序壹般在壹個swing的組件中使用,而類Jcomponent實現了圖像觀察者接口ImageObserver,所有可以使用this。
//其它情況請參考API
灰度變換
下面的程序使用三種方法對壹個彩色圖像進行灰度變換,變換的效果都不壹樣。壹般而言,灰度變換的算法是將象素的三個顏色分量使用R*0.3+G*0.59+ B*0.11得到灰度值,然後將之賦值給紅綠藍,這樣顏色取得的效果就是灰度的。另壹種就是取紅綠藍三色中的最大值作為灰度值。java核心包也有壹種算法,但是沒有看源代碼,不知道具體算法是什麽樣的,效果和上述不同。
/* GrayFilter.java*/
/*@author:cherami */
/*email:cherami@163.net*/
import java.awt.image.*;
public class GrayFilter extends RGBImageFilter {
int modelStyle;
public GrayFilter() {
modelStyle=GrayModel.CS_MAX;
canFilterIndexColorModel=true;
}
public GrayFilter(int style) {
modelStyle=style;
canFilterIndexColorModel=true;
}
public void setColorModel(ColorModel cm) {
if (modelStyle==GrayModel
else if (modelStyle==GrayModel
}
public int filterRGB(int x,int y,int pixel) {
return pixel;
}
}
/* GrayModel.java*/
/*@author:cherami */
/*email:cherami@163.net*/
import java.awt.image.*;
public class GrayModel extends ColorModel {
public static final int CS_MAX=0;
public static final int CS_FLOAT=1;
ColorModel sourceModel;
int modelStyle;
public GrayModel(ColorModel sourceModel) {
super(sourceModel.getPixelSize());
this.sourceModel=sourceModel;
modelStyle=0;
}
public GrayModel(ColorModel sourceModel,int style) {
super(sourceModel.getPixelSize());
this.sourceModel=sourceModel;
modelStyle=style;
}
public void setGrayStyle(int style) {
modelStyle=style;
}
protected int getGrayLevel(int pixel) {
if (modelStyle==CS_MAX) {
return Math.max(sourceModel.getRed(pixel),Math.max(sourceModel.getGreen(pixel),sourceModel.getBlue(pixel)));
}
else if (modelStyle==CS_FLOAT){
return (int)(sourceModel.getRed(pixel)*0.3+sourceModel.getGreen(pixel)*0.59+sourceModel.getBlue(pixel)*0.11);
}
else {
return 0;
}
}
public int getAlpha(int pixel) {
return sourceModel.getAlpha(pixel);
}
public int getRed(int pixel) {
return getGrayLevel(pixel);
}
public int getGreen(int pixel) {
return getGrayLevel(pixel);
}
public int getBlue(int pixel) {
return getGrayLevel(pixel);
}
public int getRGB(int pixel) {
int gray=getGrayLevel(pixel);
return (getAlpha(pixel)<<24)+(gray<<16)+(gray<<8)+gray;
}
}
如果妳有自己的算法或者想取得特殊的效果,妳可以修改類GrayModel的方法getGrayLevel()。
色彩變換
根據上面的原理,我們也可以實現色彩變換,這樣的效果就很多了。下面是壹個反轉變換的例子:
/* ReverseColorModel.java*/
/*@author:cherami */
/*email:cherami@163.net*/
import java.awt.image.*;
public class ReverseColorModel extends ColorModel {
ColorModel sourceModel;
public ReverseColorModel(ColorModel sourceModel) {
super(sourceModel.getPixelSize());
this.sourceModel=sourceModel;
}
public int getAlpha(int pixel) {
return sourceModel.getAlpha(pixel);
}
public int getRed(int pixel) {
return ~sourceModel.getRed(pixel);
}
public int getGreen(int pixel) {
return ~sourceModel.getGreen(pixel);
}
public int getBlue(int pixel) {
return ~sourceModel.getBlue(pixel);
}
public int getRGB(int pixel) {
return (getAlpha(pixel)<<24)+(getRed(pixel)<<16)+(getGreen(pixel)<<8)+getBlue(pixel);
}
}
/* ReverseColorModel.java*/
/*@author:cherami */
/*email:cherami@163.net*/
import java.awt.image.*;
public class ReverseFilter extends RGBImageFilter {
public ReverseFilter() {
canFilterIndexColorModel=true;
}
public void setColorModel(ColorModel cm) {
substituteColorModel(cm,new ReverseColorModel(cm));
}
public int filterRGB(int x,int y,int pixel) {
return pixel;
}
}
要想取得自己的效果,需要修改ReverseColorModel.java中的三個方法,getRed、getGreen、getBlue。
下面是上面的效果的壹個總的演示程序。
/*GrayImage.java*/
/*@author:cherami */
/*email:cherami@163.net*/
import java.awt.*;
import java.awt.image.*;
import javax.swing.*;
import java.awt.color.*;
public class GrayImage extends JFrame{
Image source,gray,gray3,clip,bigimg;
BufferedImage bimg,gray2;
GrayFilter filter,filter2;
ImageIcon ii;
ImageFilter cropFilter;
int iw,ih;
public GrayImage() {
ii=new ImageIcon(\"images/11.gif\");
source=ii.getImage();
iw=source.getWidth(this);
ih=source.getHeight(this);
filter=new GrayFilter();
filter2=new GrayFilter(GrayModel.CS_FLOAT);
gray=createImage(new FilteredImageSource(source.getSource(),filter));
gray3=createImage(new FilteredImageSource(source.getSource(),filter2));
cropFilter=new CropImageFilter(5,5,iw-5,ih-5);
clip=createImage(new FilteredImageSource(source.getSource(),cropFilter));
bigimg=source.getScaledInstance(iw*2,ih*2,Image.SCALE_DEFAULT);
MediaTracker mt=new MediaTracker(this);
mt.addImage(gray,0);
try {
mt.waitForAll();
} catch (Exception e) {
}