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Java图像处理技巧四则

作者:Cherami

email:cherami@163.net

本人的别的一些作品请查看:http://www.smiling.com.cn/group/homepage.ecgi?group_id=23141

下面代码顶用到的sourceImage是一个已经存在的Image工具

图像剪切

对付一个已经存在的Image工具,要获得它的一个局部图像,可以应用下面的步骤:

//import java.awt.*;

//import java.awt.image.*;

Image croppedImage;

ImageFilter cropFilter;

CropFilter =new CropImageFilter(25,30,75,75);//四个参数分手为图像动身点坐标和宽高,即CropImageFilter(int x,int y,int width,int height),具体环境请参考API

CroppedImage= Toolkit.getDefaultToolkit().createImage(new FilteredImageSource(sourceImage.getSource(),cropFilter));

//假如是在Component的子类中应用,可以将上面的Toolkit.getDefaultToolkit().去掉落。

//FilteredImageSource是一个ImageProducer工具。

图像缩放

对付一个已经存在的Image工具,获得它的一个缩放的Image工具可以应用Image的getScaledInstance措施:

Image scaledImage=sourceImage. getScaledInstance(100,100, Image.SCALE_DEFAULT);//获得一个100X100的图像

Image doubledImage=sourceImage. getScaledInstance(sourceImage.getWidth(this)*2,sourceImage.getHeight(this)*2, Image.SCALE_DEFAULT);//获得一个放大年夜两倍的图像,这个法度榜样一样平常在一个swing的组件中应用,而类Jcomponent实现了图像察看者接口ImageObserver,所有可以应用this。

//其它环境请参考API。

灰度变换

下面的法度榜样应用三种措施对一个彩色图像进行灰度变换,变换的效果都不一样。一样平常而言,灰度变换的算法是将象素的三个颜色分量应用R*0.3+G*0.59+B*0.11获得灰度值,然后将之赋值给红绿蓝,这样颜色取得的效果便是灰度的。另一种便是取红绿蓝三色中的最大年夜值作为灰度值。java核心包也有一种算法,然则没有看源代码,不知道详细算法是什么样的,效果和上述不合。

/* 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.CS_MAX) {

substituteColorModel(cm,new GrayModel(cm));

}

else if (modelStyle==GrayModel.CS_FLOAT) {

substituteColorModel(cm,new GrayModel(cm,modelStyle));

}

}

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;

}

}

假如你有自己的算法或者想取得特殊的效果,你可以改动类GrayModel的措施getGrayLevel()。

色彩变换

根据上面的道理,我们也可以实现色彩变换,这样的效果就很多了。下面是一个反转变换的例子:

/* 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,必要改动ReverseColorModel.java中的三个措施,getRed、getGreen、getBlue。

下面是上面的效果的一个总的演示法度榜样。

/*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) {

}

}

public void paint(Graphics g) {

Graphics2D g2=(Graphics2D)g;

bimg=new BufferedImage(iw, ih, BufferedImage.TYPE_INT_RGB);

Graphics2D srcG = bimg.createGraphics();

RenderingHints rhs = g2.getRenderingHints();

srcG.setRenderingHints(rhs);

srcG.drawImage(source, 0, 0, null);

ColorSpace graySpace=ColorSpace.getInstance(ColorSpace.CS_GRAY);

ColorConvertOp op=new ColorConvertOp(graySpace,rhs);

gray2=new BufferedImage(iw, ih, BufferedImage.TYPE_INT_RGB);

op.filter(bimg,gray2);

g2.drawImage(source,40,40,this);

g2.drawImage(gray,80,40,this);

g2.drawImage(gray2,120,40,this);

g2.drawImage(gray3,160,40,this);

g2.drawImage(clip,40,80,this);

g2.drawImage(bigimg,80,80,this);

}

public void update(Graphics g) {

paint(g);

}

public static void main(String args[]) {

GrayImage m=new GrayImage();

m.setSize(400,400);

m.setVisible(true);

}

}

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