java生成二维码图片清晰度问题

Question

二维码 

Answer 1

最后需要对图像处理一下，让白的更白，黑的更黑，图片只有两种颜色，(0, 0, 0), (255, 255, 255)，没有任何其他中间颜色。Java有函数操作卷积算法，对图像进行处理，例如模糊，锐化，浮雕等。
这有个简单的处理图像的程序，可以参考一下：
package com.tur.demo;import javax.swing.*;
import java.awt.*;
import java.awt.color.ColorSpace;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.*;
import java.io.IOException;public class ImageFilterTest {
    private static ImageFilter imageFilter = new ImageFilter("/Users/Biao/Desktop/x.png");
    private static JLabel imageLabel = new JLabel();    private static enum FilterType {
        ORIGINAL("Original Image"),
        GRAY("Gray Image"),
        BLUR("Blur Image"),
        SHARP("Sharp Image"),
        EMBOSS("Emboss Image");        private String description;        private FilterType(String description) {
            this.description = description;
        }        @Override
        public String toString() {
            return description;
        }
    };    public static JButton createImageFilterButton(final FilterType type) {
        JButton button = new JButton(type.toString());        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                Image image = null;                switch (type) {
                    case ORIGINAL:
                        image = imageFilter.getOriginalImage();
                        break;
                    case GRAY:
                        image = imageFilter.getGrayImage();
                        break;
                    case BLUR:
                        image = imageFilter.getBlurImage();
                        break;
                    case SHARP:
                        image = imageFilter.getSharpImage();
                        break;
                    case EMBOSS:
                        image = imageFilter.getEmbossImage();
                        break;
                    default:
                        image = imageFilter.getOriginalImage();
                        break;
                }                imageLabel.setIcon(new ImageIcon(image));
            }
        });        return button;
    }    private static void createAndShowGui() throws IOException {
        JFrame frame = new JFrame("Image filter");        imageLabel.setIcon(new ImageIcon(imageFilter.getOriginalImage()));
        frame.getContentPane().add(imageLabel, BorderLayout.CENTER);        JPanel buttonsPanel = new JPanel(new GridLayout(2, 3));
        buttonsPanel.add(createImageFilterButton(FilterType.ORIGINAL));
        buttonsPanel.add(createImageFilterButton(FilterType.GRAY));
        buttonsPanel.add(createImageFilterButton(FilterType.BLUR));
        buttonsPanel.add(createImageFilterButton(FilterType.SHARP));
        buttonsPanel.add(createImageFilterButton(FilterType.EMBOSS));
        frame.getContentPane().add(buttonsPanel, BorderLayout.SOUTH);        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(500, 500);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }    public static void main(String[] args) throws Exception {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    createAndShowGui();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }
}class ImageFilter {
    private BufferedImage bufImage;    public ImageFilter(String imagePath) {
        bufImage = imageToBufferedImage(new ImageIcon(imagePath).getImage());
    }    public BufferedImage getOriginalImage() {
        return bufImage;
    }    public BufferedImage getSharpImage() {
        Kernel kernel = new Kernel(3, 3, new float[]{
                -1, -1, -1,
                -1, 9, -1,
                -1, -1, -1
        });        BufferedImageOp op = new ConvolveOp(kernel);
        return op.filter(bufImage, null);
    }    public BufferedImage getBlurImage() {
        Kernel kernel = new Kernel(3, 3, new float[]{
                1f / 9f, 1f / 9f, 1f / 9f,
                1f / 9f, 1f / 9f, 1f / 9f,
                1f / 9f, 1f / 9f, 1f / 9f
        });        BufferedImageOp op = new ConvolveOp(kernel);
        return op.filter(bufImage, null);
    }    public BufferedImage getGrayImage() {
        ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
        ColorConvertOp op = new ColorConvertOp(cs, null);
        return op.filter(bufImage, null);
    }    public BufferedImage getEmbossGrayImage() {
        Kernel kernel = new Kernel(3, 3, new float[]{
                -2, 0, 0,
                0, 1, 0,
                0, 0, 2
        });        BufferedImageOp op = new ConvolveOp(kernel);
        return op.filter(bufImage, null);
    }    public BufferedImage getEmbossImage() {
        Kernel kernel = new Kernel(3, 3, new float[]{
                0,  -1, 0,
                -1, 5, -1,
                0, -1,  0
        });        BufferedImageOp op = new ConvolveOp(kernel);
        return op.filter(bufImage, null);
    }    /**
     * Convert the image to an buffered image.
     * @param image An instance of the class Image
     * @return An instance of the class BufferedImage that is converted from an image.
     */
    public static BufferedImage imageToBufferedImage(Image image) {
        int width = image.getWidth(null);
        int height = image.getHeight(null);        BufferedImage buf = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = buf.createGraphics();
        g.drawImage(image, 0, 0, width, height, null);
        g.dispose();        return buf;
    }
}

Answer 2

上述代码用eclipse直接导入报错啊。
java.lang.ExceptionInInitializerError
Caused by: java.lang.IllegalArgumentException: Width (-1) and height (-1) cannot be <= 0
at java.awt.image.DirectColorModel.createCompatibleWritableRaster(DirectColorModel.java:999)
at java.awt.image.BufferedImage.<init>(BufferedImage.java:312)
at com.tur.demo.ImageFilter.imageToBufferedImage(ImageFilterTest.java:173)
at com.tur.demo.ImageFilter.<init>(ImageFilterTest.java:107)
at com.tur.demo.ImageFilterTest.<clinit>(ImageFilterTest.java:13)
求解释

Answer 3

可以的，生成二维码的时候有设置的,
 g.DrawImage(backgroundImg.Image, new System.Drawing.Rectangle(x, y, backgroundImg.Image.Width, backgroundImg.Image.Height),
                            new System.Drawing.Rectangle(0, 0, backgroundImg.Image.Width, backgroundImg.Image.Height),
                            GraphicsUnit.Pixel);