图像处理之文字轧花效果- 简单数字水印 @ gloomyfish
首先看一下效果，左边是一张黑白的文字图像，右边是混合之后的数字水印效果
实现原理
主要是利用位图块迁移算法，首先提取文字骨架，宽度为一个像素。然后将提取的骨架，按
照一定的像素值填充到目标图像中即可。关于位图块迁移算法说明请看这里：
http://en.wikipedia.org/wiki/Bit_blit
程序思路：
1. 首先创建两张白板的单色位图，读入黑白文字图片，
2. 移动一个像素位开始读取文字图片中的像素，将每个对应像素与白板单色图片叠加，直
至黑白文字图片完全copy到单色白板中。
3. 重复上面操作，唯一不同的，将白板像素移动一个像素为，以后开始填充
4. 分别将两张位图块迁移图片与原黑白文字图片像素完成一个或操作，则得到左上和右下
的文字骨架。
5. 将两个文字骨架的像素填充到目标彩色图片中，即得到轧花效果的图片
根据输入参数不同，还可得到雕刻效果图片。
关键代码解释：
实现位图块迁移算法的代码如下：
// one pixel transfer
for(int row=1; row<height; row++) {
int ta = 0, tr = 0, tg = 0, tb = 0;
for(int col=1; col<width; col++) {
index = row * width + col;
index2 = (row-1) * width + (col-1);
ta = (inPixels[isTop?index:index2] >> 24) & 0xff;
tr = (inPixels[isTop?index:index2] >> 16) & 0xff;
tg = (inPixels[isTop?index:index2] >> 8) & 0xff;
tb = inPixels[isTop?index:index2] & 0xff;
outPixels[isTop?index2:index] = (ta << 24) | (tr<< 16) | (tg << 8) | tb;
}
}
布尔变量isTop决定是否填充单色白板位移(Offset)是零还是一。
获取一个像素宽度骨架的方法为processonePixelWidth()主要是利用文字图片是一个二值图像，
从而remove掉多余的像素。
混合轧花的方法为embossImage()主要是简单的像素填充，布尔变量主要是用来控制是凹轧花
还是凸轧花效果。所有对文字图像的处理和轧花效果的处理封装在BitBltFilter一个类中.
程序效果如下：
位图块位移算法实现完全源代码如下：
package com.gloomyfish.zoom.study;
import java.awt.image.BufferedImage;
import com.process.blur.study.AbstractBufferedImageOp;
public class BitBltFilter extends AbstractBufferedImageOp {
// raster operation - bit block transfer.
// 1975 for the Smalltalk-72 system, For the Smalltalk-74 system
private boolean isTop = true;
/**
* left - top skeleton or right - bottom.
*
* @param isTop
*/
public void setTop(boolean isTop) {
this.isTop = isTop;
}
/**
* blend the pixels and get the final output image
*
* @param textImage
* @param targetImage
*/
public void emboss(BufferedImage textImage, BufferedImage targetImage) {
// BitBltFilter filter = new BitBltFilter();
BufferedImage topImage = filter(textImage, null);
setTop(false);
BufferedImage buttomImage = filter(textImage, null);
int width = textImage.getWidth();
int height = textImage.getHeight();
int[] inPixels = new int[width*height];
int[] outPixels = new int[width*height];
getRGB( textImage, 0, 0, width, height, inPixels );
getRGB( topImage, 0, 0, width, height, outPixels );
processonePixelWidth(width, height, inPixels, outPixels, topImage);
getRGB( buttomImage, 0, 0, width, height, outPixels );
processonePixelWidth(width, height, inPixels, outPixels, buttomImage);
// emboss now
embossImage(topImage, targetImage, true);
embossImage(buttomImage, targetImage, false);
}
@Override
public BufferedImage filter(BufferedImage src, BufferedImage dest) {
int width = src.getWidth();
int height = src.getHeight();
if ( dest == null )
dest = createCompatibleDestImage(src, null);
int[] inPixels = new int[width*height];
int[] outPixels = new int[width*height];
getRGB( src, 0, 0, width, height, inPixels );
int index = 0;
int index2 = 0;
// initialization outPixels
for(int row=0; row<height; row++) {
for(int col=0; col<width; col++) {
index = row * width + col;
outPixels[index] = (255 << 24) | (255 << 16) | (255 << 8) | 255;
}
}
// one pixel transfer
for(int row=1; row<height; row++) {
int ta = 0, tr = 0, tg = 0, tb = 0;
for(int col=1; col<width; col++) {
index = row * width + col;
index2 = (row-1) * width + (col-1);
ta = (inPixels[isTop?index:index2] >> 24) & 0xff;
tr = (inPixels[isTop?index:index2] >> 16) & 0xff;
tg = (inPixels[isTop?index:index2] >> 8) & 0xff;
tb = inPixels[isTop?index:index2] & 0xff;
outPixels[isTop?index2:index] = (ta << 24) | (tr << 16) | (tg << 8) | tb;
}
}
setRGB( dest, 0, 0, width, height, outPixels );
return dest;
}
/**
*
* @param width
* @param height
* @param inPixels
* @param outPixels
* @param destImage
*/
private void processonePixelWidth(int width, int height, int[] inPixels, int[] outPixels, BufferedImage destImage) {
// now get one pixel data
int index = 0;
for(int row=0; row<height; row++) {
int ta = 0, tr = 0, tg = 0, tb = 0;
int ta2 =0, tr2 = 0, tg2 = 0, tb2 = 0;
for(int col=0; col<width; col++) {
index = row * width + col;
ta = (inPixels[index] >> 24) & 0xff;
tr = (inPixels[index] >> 16) & 0xff;
tg = (inPixels[index] >> 8) & 0xff;
tb = inPixels[index] & 0xff;
ta2 = (outPixels[index] >> 24) & 0xff;
tr2 = (outPixels[index] >> 16) & 0xff;
tg2 = (outPixels[index] >> 8) & 0xff;
tb2 = outPixels[index] & 0xff;
if(tr2 == tr && tg == tg2 && tb == tb2) {
outPixels[index] = (255 << 24) | (255 << 16) | (255 << 8) | 255;
} else {
if(tr2 < 5 && tg2 < 5 && tb2 < 5) {
outPixels[index] = (ta2 << 24) | (tr2 << 16) | (tg2 << 8) | tb2;
} else {
outPixels[index] = (255 << 24) | (255 << 16) | (255 << 8) | 255;
}
}
}
}
setRGB( destImage, 0, 0, width, height, outPixels );
}
/**
*
* @param src
* @param dest
* @param colorInverse - must be setted here!!!
*/
private void embossImage(BufferedImage src, BufferedImage dest, boolean colorInverse)
{
int width = src.getWidth();
int height = src.getHeight();
int dw = dest.getWidth();
int dh = dest.getHeight();
int[] sinPixels = new int[width*height];
int[] dinPixels = new int[dw*dh];
src.getRGB( 0, 0, width, height, sinPixels, 0, width );
dest.getRGB( 0, 0, dw, dh, dinPixels, 0, dw );
int index = 0;
int index2 = 0;
for ( int y = 0; y < height; y++ ) {
for ( int x = 0; x < width; x++ ) {
index = y * width + x;
int srgb = sinPixels[index];
int r1 = (srgb >> 16) & 0xff;
int g1 = (srgb >> 8) & 0xff;
int b1 = srgb & 0xff;
if(r1 > 200 || g1 >=200 || b1 >=200) {
continue;
}
index2 = y * dw + x;
if(colorInverse) {
r1 = 255 - r1;
g1 = 255 - g1;
b1 = 255 - b1;
}
dinPixels[index2] = (255 << 24) | (r1 << 16) | (g1 << 8) | b1;
}
}
dest.setRGB( 0, 0, dw, dh, dinPixels, 0, dw );
}
}
程序测试代码如下：
package com.gloomyfish.zoom.study;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JComponent;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
public class BitBltFilterTest extends JComponent {
/**
*
*/
private static final long serialVersionUID = 7462704254856439832L;
private BufferedImage rawImg;
private BufferedImage modImg;
private Dimension mySize;
public BitBltFilterTest(File f) {
try {
rawImg = ImageIO.read(f);
modImg = ImageIO.read(new File("D:\\resource\\geanmm.png"));
// modImg = ImageIO.read(new File("D:\\resource\\gloomyfish.png"));
} catch (IOException e) {
e.printStackTrace();
}
mySize = new Dimension(2*modImg.getWidth() + 20, modImg.getHeight()+ 100);
filterImage();
final JFrame imageFrame = new JFrame("Emboss Text - gloomyfish");
imageFrame.getContentPane().setLayout(new BorderLayout());
imageFrame.getContentPane().add(this, BorderLayout.CENTER);
imageFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
imageFrame.pack();
imageFrame.setVisible(true);
}
private void filterImage() {
BitBltFilter filter = new BitBltFilter();
filter.emboss(rawImg, modImg);
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.drawImage(rawImg, 0, 0, rawImg.getWidth(), rawImg.getHeight(), null);
g2.drawImage(modImg, rawImg.getWidth()+10, 0, modImg.getWidth(), modImg.getHeight(), null);
g2.drawString("text image", rawImg.getWidth()/2, rawImg.getHeight()+10);
g2.drawString("sharped text in image", modImg.getWidth() + 10, modImg.getHeight()+10);
}
public Dimension getPreferredSize() {
return mySize;
}
public Dimension getMinimumSize() {
return mySize;
}
public Dimension getMaximumSize() {
return mySize;
}
public static void main(String[] args) {
JFileChooser chooser = new JFileChooser();
chooser.showOpenDialog(null);
File f = chooser.getSelectedFile();
new BitBltFilterTest(f);
}
}
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