java - 在java中读/写图像

Question

我想使用java来读取/写入图像，并且我有一些代码。但我不知道如何使用这些代码，尤其是在参数 String...

中

实际上在这些代码附带的示例demo中，用法是这样的:

double[] data = Image.load("src/chap08_romsrams/common/lena256.ppm", "../common/lena256.ppm");

还有这个:

Image.write(l, "P3", 256, "src/chap08_romsrams/ex1_roms/lena_processed.ppm", "lena_processed.ppm");

假设我有一个名为 lena.ppm 的 256*256 图像，它与 java 文件位于同一文件夹中，我如何使用这些函数来读取/写入图像...？

非常感谢!

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Image {
public static double[] load(String... fn) {
    InputStream in = null;

    for (String string : fn) {
        try {
            in = new FileInputStream(string);
        } catch (IOException e) {
            /* Empty */
        }
        if (in != null) break;
    }

    if (in == null) {
        throw new RuntimeException("Failed to load input image in Image.load(String...), tried to load image from " + fn);
    }

    BufferedReader reader = new BufferedReader( new InputStreamReader(in) );

    try {
        String type = reader.readLine(); // Type
        reader.readLine(); // Comment
        String res = reader.readLine(); // Dimensions
        reader.readLine(); // Intensity range

        Pattern p = Pattern.compile("(\\d+) (\\d+)");
        Matcher m = p.matcher(res);
        m.matches();
        Integer width = Integer.parseInt(m.group(1));
        Integer height = Integer.parseInt(m.group(2));

        System.err.println(width + "x" + height);

        double[] data = new double[width * height * ((type.equals("P3")) ? 3 : 1)];
        String line;
        int i = 0;
        while((line = reader.readLine()) != null)
            data[i++] = Integer.parseInt(line);

        reader.close();

        return data;

    } catch(IOException e) {
        throw new RuntimeException(e);
    }
}

public static void write(List<Double> data, String... fn) {
    write(data, "P2", 1024, fn);
}

public static void write(List<Double> data, String type, int width, String... fn) {
    OutputStream out = null;

    for (String string : fn) {
        try {
            out = new FileOutputStream(string);
        } catch (IOException e) {
            /* Empty */
        }
        if (out != null) break;
    }

    if (out == null) {
        throw new RuntimeException("Failed to file for output in Image.write(List<Double>, String, int, String...), tried to open " + fn);
    }

    PrintStream ps = new PrintStream(out);

    ps.println(type);
    int height = data.size() / (width * ((type.equals("P3") ? 3 : 1))); //1024;
    ps.println("#generated");
    ps.println("" + width + " " + height);
    ps.println("255");
    for(Double d : data)
        ps.println((int)(d.doubleValue()));
}

}

Answer 1

你为什么不试试Java Imaging API 。这是example如何进行图像 IO。希望这有帮助..