Background image and QR code synthesis

demand : It is similar to making a code card , UI Provide background image template , The back end synthesizes the QR code into the background image template

Background image template                                                 Final rendering

 

Open up

package cc.sunni;

import cn.hutool.core.util.StrUtil;
import cn.hutool.extra.qrcode.QrCodeUtil;
import cn.hutool.extra.qrcode.QrConfig;
import org.springframework.core.io.ClassPathResource;
import sun.misc.BASE64Encoder;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;

/**
 *  Code card :  Synthesize the QR code into the background picture 
 *
 * @author  Jiang Li 
 * @since 2022-07-21
 */
public class QrCodeCard {

    /**
     *  The width of the QR code 
     */
    private static final int QR_CODE_WIDTH = 640;
    /**
     *  The height of the QR code 
     */
    private static final int QR_CODE_HEIGHT = 640;
    /**
     * title typeface 
     */
    private static final Font TITLE_FONT = new Font(" Song style ", Font.BOLD, 30);
    /**
     * desc typeface 
     */
    private static final Font DESC_FONT = new Font(" Song style ", Font.PLAIN, 25);
    /**
     * bottom typeface 
     */
    private static final Font BOTTOM_FONT = new Font(" Song style ", Font.ITALIC, 24);

    private static final String FORMAT_NAME = "PNG";

    /**
     * @param title            title 
     * @param desc             describe 
     * @param content          QR code content 
     * @param bottom           Bottom text 
     * @param imgLogo          QR code middle picture address 
     * @param backgroundImage  Background image address 
     * @param imageY           QR code in the background picture Y Axis position , X The axis is centered 
     * @return  return BufferedImage It is convenient for subsequent processing to generate pictures or base64 character string 
     */
    public static BufferedImage createQrCode(String title, String desc, String content, String bottom, String imgLogo, String backgroundImage, int imageY) throws IOException {
        //  Create a master template image 
        int maxWidth = getMaxWidth(title, desc, bottom);
        int maxHeight = getMaxHeight();
        BufferedImage image = new BufferedImage(maxWidth, maxHeight, BufferedImage.TYPE_INT_RGB);
        Graphics2D graphics = image.createGraphics();
        if (StrUtil.isNotBlank(backgroundImage)) {
            //  Set the background color of the picture to transparent ,  If you need to synthesize to the background image, set it to transparent 
            image = graphics.getDeviceConfiguration().createCompatibleImage(maxWidth, maxHeight, Transparency.TRANSLUCENT);
        } else {
            //  Set the background color of the picture to white 
            graphics.setColor(Color.white);
        }

        graphics.fillRect(0, 0, maxWidth, maxHeight);

        //  Dynamic height 
        int height = 0;

        // *********************** title ***********************
        if (StrUtil.isNotBlank(title)) {
            graphics = image.createGraphics();
            //  Set font color  black black  white white 
            graphics.setColor(Color.black);
            //  Set the font 
            graphics.setFont(TITLE_FONT);
            graphics.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_LCD_HRGB);
            //  In the middle  x Starting position ：（ Image width - font size * The number of words ）/2
            int x = (maxWidth - (TITLE_FONT.getSize() * title.length())) / 2;
            int strHeight = getStringHeight(graphics);
            graphics.drawString(title, x, strHeight);
            height += strHeight;
        }

        // ********************** desc **********************
        if (StrUtil.isNotBlank(desc)) {
            graphics = image.createGraphics();
            //  Set font color , Set the color first , Refill content 
            graphics.setColor(Color.black);
            //  Set the font 
            graphics.setFont(DESC_FONT);
            graphics.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_LCD_HRGB);
            //  Gets the character height 
            int strHeight = getStringHeight(graphics);
            //  Center by line 
            String[] info = desc.split("\\$");  //  Multiline text with  $  Separate 
            for (int i = 0; i < info.length; i++) {
                String s = info[i];
                // x Starting position ：（ Image width - font size * The number of words ）/2
                int strWidth = graphics.getFontMetrics().stringWidth(s);
                //  The total length minus half the length of the text   （ centered ）
                int startX = (maxWidth - strWidth) / 2;
                height += strHeight * (i + 1);
                graphics.drawString(s, startX, height);
            }
        }

        // **********************  Insert QR code picture  **********************
        Graphics codePic = image.getGraphics();
        BufferedImage codeImg;
        QrConfig config = new QrConfig();
        config.setMargin(2);
        config.setWidth(QR_CODE_WIDTH);
        config.setHeight(QR_CODE_HEIGHT);
        if (StrUtil.isNotBlank(imgLogo)) {
            config.setImg(imgLogo);
        }
        codeImg = QrCodeUtil.generate(content, config);
        //  Draw qr code 
        codePic.drawImage(codeImg, (maxWidth - QR_CODE_WIDTH) / 2, height, QR_CODE_WIDTH, QR_CODE_HEIGHT, null);
        codePic.dispose();

        // ********************** bottom **********************
        if (StrUtil.isNotBlank(bottom)) {
            graphics = image.createGraphics();
            //  Set font color 
            graphics.setColor(Color.black);
            //  Set the font 
            graphics.setFont(BOTTOM_FONT);
            graphics.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_LCD_HRGB);
            // x Starting position ：（ Image width - font size * The number of words ）/2
            int startX = (maxWidth - (BOTTOM_FONT.getSize() * bottom.length())) / 2;
            //  Gets the character height 
            int footerStrHeight = getStringHeight(graphics);
            height += QR_CODE_HEIGHT + footerStrHeight;
            graphics.drawString(bottom, startX, height);
        }

        if (StrUtil.isNotBlank(backgroundImage)) {
            //  Load the background template 
            ClassPathResource resource = new ClassPathResource(backgroundImage);
            InputStream inputStream = resource.getInputStream();
            BufferedImage templateImage = ImageIO.read(inputStream);
            Graphics graphicsTemplate = templateImage.getGraphics();
            //  According to the template width  -  QR code width   Calculate by centering X coordinate 
            int widthX = (templateImage.getWidth() - image.getWidth()) / 2;
            //  Add QR code 
            graphicsTemplate.drawImage(image, widthX, imageY, null);
            graphicsTemplate.dispose();
            return templateImage;
        } else {
            return image;
        }
    }

    //  Generate image file 
    public static void createImage(BufferedImage image, String fileLocation) {
        if (image != null) {
            try {
                ImageIO.write(image, "png", new File(fileLocation));
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    //  Get photo base64 data 
    public static String base64ImageString(BufferedImage image) throws IOException {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();//io flow 
        ImageIO.write(image, FORMAT_NAME, bos);// Write to the stream 
        byte[] bytes = bos.toByteArray();// Convert to bytes 
        BASE64Encoder encoder = new BASE64Encoder();
        String jpgBase64 = encoder.encodeBuffer(bytes).trim();// convert to base64 strand 
        jpgBase64 = jpgBase64.replaceAll("\n", "").replaceAll("\r", "");// Delete  \r\n
        return "data:image/jpg;base64," + jpgBase64;
    }

    //  Total string width 
    private static int getStringLength(Graphics g, String str) {
        char[] chars = str.toCharArray();
        return g.getFontMetrics().charsWidth(chars, 0, str.length());
    }

    //  character height 
    private static int getStringHeight(Graphics g) {
        return g.getFontMetrics().getHeight();
    }

    //  The number of characters in each line 
    private static int getRowStrNum(int strNum, int rowWidth, int strWidth) {
        return (rowWidth * strNum) / strWidth;
    }

    //  Number of character lines 
    private static int getRows(int strWidth, int rowWidth) {
        int rows;
        if (strWidth % rowWidth > 0) {
            rows = strWidth / rowWidth + 1;
        } else {
            rows = strWidth / rowWidth;
        }
        return rows;
    }

    //  Calculate the maximum width of the QR code picture 
    private static int getMaxWidth(String title, String desc, String bottom) {
        int width = 0;
        BufferedImage image = new BufferedImage(QR_CODE_WIDTH, QR_CODE_HEIGHT, BufferedImage.TYPE_INT_RGB);
        Graphics2D graphics = image.createGraphics();
        if (StrUtil.isNotBlank(title)) {
            width = Math.max(getStringLength(graphics, title), width);
        }
        if (StrUtil.isNotBlank(desc)) {
            width = Math.max(getStringLength(graphics, desc), width);
        }
        if (StrUtil.isNotBlank(bottom)) {
            width = Math.max(getStringLength(graphics, bottom), width);
        }
        return Math.max(QR_CODE_WIDTH, width);
    }

    //  Calculate the maximum height of the QR code image 
    private static int getMaxHeight() {
        int height = QR_CODE_HEIGHT;
        BufferedImage image = new BufferedImage(QR_CODE_WIDTH, QR_CODE_HEIGHT, BufferedImage.TYPE_INT_RGB);
        Graphics2D graphics = image.createGraphics();
        graphics.setFont(TITLE_FONT);
        height += getStringHeight(graphics);
        graphics.setFont(DESC_FONT);
        height += getStringHeight(graphics);
        graphics.setFont(BOTTOM_FONT);
        height += getStringHeight(graphics);
        return height;
    }

    public static void main(String[] args) throws IOException {
        String title = " Code card ";
        String desc = " Well known Internet companies CEO";
        String content = "https://www.baidu.com";
        String logo = "templates/[email protected]";
        String bottom = " National Certification ";
        String backgroundImage = "templates/announcer.png";
//        BufferedImage bufferedImage = createQrCode(null, null, content, logo, null, backgroundImage, 290);
        BufferedImage bufferedImage = createQrCode(title, desc, content, logo, bottom, backgroundImage, 290);
        createImage(bufferedImage, "D:/test.png");
    }
}

Without background                         ​​​​​​​        ​​​​​​​        ​​​​​​​        ​​​​​​​                  With background

 

  Attach the download method
​​​​

@RestController
public class Controller {

    @PostMapping("/downloadQrCode")
    public void downloadQrCode(@RequestParam String content, @RequestParam(required = false) String title,
                               @RequestParam(required = false) String desc, @RequestParam(required = false) String bottom,
                               HttpServletResponse response) throws IOException {
        BufferedImage targetBufferedImage = QrCodeCard.createQrCode(title, desc, content,
                bottom, "templates/[email protected]", "templates/announcer.png", 290);
        OutputStream os = response.getOutputStream();
        response.setCharacterEncoding(Charsets.UTF_8.name());
        response.setContentType("multipart/form-data");
        response.setHeader("content-type", "image/png");
        ImageIO.write(targetBufferedImage, "png", os);
    }
}