Java，java.awt.image.BufferedImage
Java，BufferedImage是Image的子类，用于处理和操纵图像数据，BufferedImage由图像数据的ColorModel组成，所有BufferedImage对象的左上角坐标为（0,0）。
代码案例1，BufferedImage图片：
package com.what21.image01.demo01;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
public class ImageTest01 {
public static void main(String[] args) throws Exception {
BufferedImage image = ImageIO.read(new File("D:\\test.jpg"));
System.out.println("image.width " + image.getWidth()); // 800
System.out.println("image.height " + image.getHeight()); // 444
Graphics2D g = (Graphics2D) image.getGraphics();
Color color = new Color(123, 0, 35);
g.setColor(color);
Font font = new Font("宋体", Font.BOLD, 165);
g.setFont(font);
g.drawString("IT小奋斗", 40, 240);
ImageIO.write(image, "jpg", new File("D:\\test-1.jpg"));
}
}效果：
代码案例2，JFrame中使用：
package com.what21.image01.demo01;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
public class ImageTest02 extends JPanel {
public void paint(Graphics g) {
Image img = createImageWithText();
// 画图
g.drawImage(img, 20, 20, this);
}
private Image createImageWithText() {
BufferedImage bufferedImage = new BufferedImage(500, 300, BufferedImage.TYPE_INT_RGB);
Graphics g = bufferedImage.getGraphics();
Color color = new Color(123, 0, 123);
g.setColor(color);
Font font = new Font("宋体", Font.BOLD, 30);
g.setFont(font);
g.drawString("IT小奋斗", 20, 40);
g.drawString("IT小奋斗", 20, 80);
g.drawString("IT小奋斗", 20, 120);
g.drawString("IT小奋斗", 20, 160);
g.drawString("IT小奋斗", 20, 200);
return bufferedImage;
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.getContentPane().add(new ImageTest02());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(800, 600);
frame.setVisible(true);
}
}
Java，BufferedImage与OpenCV，org.opencv.core.Mat相互转换
代码案例：
package com.what21.opencv01.demo02;
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.imgcodecs.Imgcodecs;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
public class BufferedImageOpenCVDemo {
static {
// 保证先执行该语句，用于加载库
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
}
public static void main(String[] args) throws Exception {
// OpenCV Mat 转换为 BufferedImage
Mat source = Imgcodecs.imread("D:\\demo.jpg");
BufferedImage image = BufferedImageOpenCVUtils.mat2BufferedImage(source);
System.out.println("image.width " + image.getWidth());
System.out.println("image.height " + image.getHeight());
ImageIO.write(image, "jpg", new File("D:\\demo.1.jpg"));
BufferedImage targetImage = BufferedImageOpenCVUtils.matToBufferedImage(source);
ImageIO.write(image, "jpg", new File("D:\\demo.2.jpg"));
// BufferedImage转换为 OpenCV Mat
BufferedImage image2 = ImageIO.read(new File("D:\\demo.jpg"));
Mat target = BufferedImageOpenCVUtils.bufferedImageToMat(image2);
Imgcodecs.imwrite("D:\\demo.3.jpg", target);
//
Mat target2 = BufferedImageOpenCVUtils.img2Mat(image2);
Imgcodecs.imwrite("D:\\demo.4.jpg", target2);
}
}
package com.what21.opencv01.demo02;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.MatOfByte;
import org.opencv.imgcodecs.Imgcodecs;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.awt.image.WritableRaster;
import java.io.ByteArrayInputStream;
import java.io.IOException;
public class BufferedImageOpenCVUtils {
/**
* @param matrix
* @return
* @throws IOException
*/
public static BufferedImage mat2BufferedImage(Mat matrix) throws IOException {
MatOfByte mob = new MatOfByte();
Imgcodecs.imencode(".jpg", matrix, mob);
return ImageIO.read(new ByteArrayInputStream(mob.toArray()));
}
/**
* @param image
* @return
*/
public static Mat bufferedImageToMat(BufferedImage image) {
Mat mat = new Mat(image.getHeight(), image.getWidth(), CvType.CV_8UC3);
byte[] data = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
mat.put(0, 0, data);
return mat;
}
/**
* @param in
* @return
*/
public static Mat img2Mat(BufferedImage in) {
Mat out;
byte[] data;
int r, g, b;
if (in.getType() == BufferedImage.TYPE_INT_RGB) {
out = new Mat(in.getHeight(), in.getWidth(), CvType.CV_8UC3);
data = new byte[in.getWidth() * in.getHeight() * (int) out.elemSize()];
int[] dataBuff = in.getRGB(0, 0, in.getWidth(), in.getHeight(), null, 0, in.getWidth());
for (int i = 0; i < dataBuff.length; i++) {
data[i * 3] = (byte) ((dataBuff[i] >> 0) & 0xFF);
data[i * 3 + 1] = (byte) ((dataBuff[i] >> 8) & 0xFF);
data[i * 3 + 2] = (byte) ((dataBuff[i] >> 16) & 0xFF);
}
} else {
out = new Mat(in.getHeight(), in.getWidth(), CvType.CV_8UC1);
data = new byte[in.getWidth() * in.getHeight() * (int) out.elemSize()];
int[] dataBuff = in.getRGB(0, 0, in.getWidth(), in.getHeight(), null, 0, in.getWidth());
for (int i = 0; i < dataBuff.length; i++) {
r = (byte) ((dataBuff[i] >> 0) & 0xFF);
g = (byte) ((dataBuff[i] >> 8) & 0xFF);
b = (byte) ((dataBuff[i] >> 16) & 0xFF);
data[i] = (byte) ((0.21 * r) + (0.71 * g) + (0.07 * b));
}
}
out.put(0, 0, data);
return out;
}
/**
* @param frame
* @return
*/
public static BufferedImage matToBufferedImage(Mat frame) {
int type = 0;
if (frame.channels() == 1) {
type = BufferedImage.TYPE_BYTE_GRAY;
} else if (frame.channels() == 3) {
type = BufferedImage.TYPE_3BYTE_BGR;
}
BufferedImage image = new BufferedImage(frame.width(), frame.height(), type);
WritableRaster raster = image.getRaster();
DataBufferByte dataBuffer = (DataBufferByte) raster.getDataBuffer();
byte[] data = dataBuffer.getData();
frame.get(0, 0, data);
return image;
}
}Java，BufferedImage与JavaCV，org.bytedeco.javacpp.opencv_core.Mat相互转换
org.opencv.core.Mat与org.bytedeco.javacpp.opencv_core.Mat，两种Mat格式，两者不互通，导入的依赖包也不同，Mat格式转换先将org.opencv.core.Mat转化为java.awt.image.BufferedImage，再将BufferImage转化为org.bytedeco.javacpp.opencv_core.Mat格式。
代码案例：
package com.what21.javacv01.demo02;
import org.bytedeco.javacv.Java2DFrameConverter;
import org.bytedeco.javacv.Java2DFrameUtils;
import org.bytedeco.javacv.OpenCVFrameConverter;
import org.bytedeco.opencv.global.opencv_imgcodecs;
import org.bytedeco.opencv.opencv_core.Mat;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
public class BufferedImageJavaCVDemo {
public static void main(String[] args) throws Exception {
// BufferedImage转换为JavaCV Mat
BufferedImage image = ImageIO.read(new File("D:\\demo.jpg"));
Mat mat1 = Java2DFrameUtils.toMat(image);
opencv_imgcodecs.imwrite("D:\\demo_1.jpg", mat1);
Mat mat2 = bufferedImageToMat(image);
opencv_imgcodecs.imwrite("D:\\demo_2.jpg", mat2);
// JavaCV Mat转换为BufferedImage
BufferedImage targetImage = Java2DFrameUtils.toBufferedImage(mat1);
ImageIO.write(targetImage, "jpg", new File("D:\\demo_3.jpg"));
}
/**
* @param bi
* @return
*/
public static Mat bufferedImageToMat(BufferedImage bi) {
OpenCVFrameConverter.ToMat cv = new OpenCVFrameConverter.ToMat();
return cv.convertToMat(new Java2DFrameConverter().convert(bi));
}
}
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