zxing生成二维码去白边

淩亂°似流年 2021-06-24 15:57 526阅读 0赞

今天遇到了二维码生成的图片需要切掉白边的情况，查看之前的二维码生成代码，发现有这么一行

hints.put(EncodeHintType.MARGIN, 1);

感觉应该是设置边距的意思，果断改成

hints.put(EncodeHintType.MARGIN, 0);

发现其实并不能去掉白边。

于是百度找到方案：

private static BufferedImage getNormalQRCode(String content) throws WriterException {
            Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
            hints.put(EncodeHintType.CHARACTER_SET, CHARSET);
            hints.put(EncodeHintType.MARGIN, 1);
            BitMatrix bitMatrix = new MultiFormatWriter().encode(content,
                    BarcodeFormat.QR_CODE, QRCODE_SIZE, QRCODE_SIZE, hints);
            //调用去除白边方法
            bitMatrix = deleteWhite(bitMatrix);
            int width = bitMatrix.getWidth();
            int height = bitMatrix.getHeight();
            BufferedImage image = new BufferedImage(width, height,
                    BufferedImage.TYPE_INT_RGB);
            for (int x = 0; x < width; x++) {
                for (int y = 0; y < height; y++) {
                    image.setRGB(x, y, bitMatrix.get(x, y) ? BLACK //int 0
                            : WHITE //int 255);
                }
            }
            return image;
        }
    ImageIO.write(image, "jpg", response.getOutputStream());  
    
        private static BitMatrix deleteWhite(BitMatrix matrix) {
            int[] rec = matrix.getEnclosingRectangle();
            int resWidth = rec[2] + 1;
            int resHeight = rec[3] + 1;
    
            BitMatrix resMatrix = new BitMatrix(resWidth, resHeight);
            resMatrix.clear();
            for (int i = 0; i < resWidth; i++) {
                for (int j = 0; j < resHeight; j++) {
                    if (matrix.get(i + rec[0], j + rec[1]))
                        resMatrix.set(i, j);
                }
            }
            return resMatrix;
        }

搞定

最近项目里需要生成一些二维码，使用之后发现一些问题，生成之后的图片，白色边框区域太大了，导致二维码内容区域太小。 
    百度了一下，有人说设置EncodeHintType.MARGIN属性即可，这个属性值为1-4，实际测试发现并没有什么卵用。（顺便说一下，一些比较老的版本中，这个EncodeHintType只有CHARACTER_SET和ERROR_CORRECTION两种属性设置，比较新的库才新增了其他属性，我这里使用的是3.0版本） 
    后来找到另外一个解决办法：自己手动去除黑边，代码如下：
    
    public static Bitmap Create2DCode(String str, int width, int height) {
            try {
                Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
                hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
                hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
                hints.put(EncodeHintType.MARGIN, 1);
                BitMatrix matrix = new QRCodeWriter().encode(str, BarcodeFormat.QR_CODE, width, height);
                matrix = deleteWhite(matrix);//删除白边
                width = matrix.getWidth();
                height = matrix.getHeight();
                int[] pixels = new int[width * height];
                for (int y = 0; y < height; y++) {
                    for (int x = 0; x < width; x++) {
                        if (matrix.get(x, y)) {
                            pixels[y * width + x] = Color.BLACK;
                        } else {
                            pixels[y * width + x] = Color.WHITE;
                        }
                    }
                }
                Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
                bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
                return bitmap;
            } catch (Exception e) {
                return null;
            }
        }
    
    
        private static BitMatrix deleteWhite(BitMatrix matrix) {
            int[] rec = matrix.getEnclosingRectangle();
            int resWidth = rec[2] + 1;
            int resHeight = rec[3] + 1;
    
            BitMatrix resMatrix = new BitMatrix(resWidth, resHeight);
            resMatrix.clear();
            for (int i = 0; i < resWidth; i++) {
                for (int j = 0; j < resHeight; j++) {
                    if (matrix.get(i + rec[0], j + rec[1]))
                        resMatrix.set(i, j);
                }
            }
            return resMatrix;
        }