emis-app/components/tpx-bluetooth-print/print/printJob.js

//微信小程序向蓝牙打印机发送数据进行打印的坑：
//小程序api向蓝牙打印机发送数据打印，发送的任何内容都应该要转成二进制数据，而且蓝牙打印的文本编码是GBK的，发送中文需转成GBK编码再转成二进制数据发送
//发送打印机指令也要转成二进制数据发送
//蓝牙打印机一次接收的二级制数据有限制，不同的系统不同的蓝牙设备限制可能不同，微信建议一次20个字节，需做递归分包发送
//发送完要打印的内容后，一定要发送一个打印的指令才能顺利打印 （有些指令就不需要）

/**
 *
 *
 * @export
 * @param {object} options
 * {
            deviceId,
            serviceId,
            characteristicId,
			value [ArrayBuffer],
			lasterSuccess,
    }
 */
		
export function sendDataToDevice(options) {
    let byteLength = options.value.byteLength;
    // 这里默认一次20个字发送
    const speed = options.onceByleLength || 20;
	console.log('byteLength====', byteLength)
    if (byteLength > 0) {
		console.log('speed====', speed)
		console.log('value====', options.value)
        uni.writeBLECharacteristicValue({
            ...options,
            // writeType:"writeNoResponse",
            value: options.value.slice(0, byteLength > speed ? speed : byteLength),
            success: function (res) {
				// 【writeBLECharacteristicValue】安卓存在频繁调用失败的情况，下次调用前必须加上延迟
				setTimeout(()=> {
					if (byteLength > speed) {
					    sendDataToDevice({
					        ...options,
					        value: options.value.slice(speed, byteLength),
					    });
					} else {
					    options.lasterSuccess && options.lasterSuccess();
					}
				},10)
            },
            fail: function (res) {
				console.log('writeBLECharacteristicValue:fail====', res)
                options.onError && options.onError(res);
            },
        });
    }
}
export function charToArrayBuffer(str) {
    var out = new ArrayBuffer(str.length);
    var uint8 = new Uint8Array(out);
    var strs = str.split('');
    for (var i = 0; i < strs.length; i++) {
        uint8[i] = strs[i].charCodeAt();
    }
    return uint8;
}
export function charToArray(str) {
    var arr = [];
    var strs = str.split('');
    for (var i = 0; i < strs.length; i++) {
        arr[i] = strs[i].charCodeAt();
    }
    return arr;
}

// 使用的 ESC/POS指令， 十进制方式
// 更多指令请查看 ./PrintCommandDocs/ESC-POS指令文档(凯盛诺打印机代表).pdf

export const printCommand = {
    left: [27, 97, 0], //居左
    center: [27, 97, 1], //居中
    right: [27, 97, 2], //居右
    clear: [27, 64], //初始化
    enter: [10],
};

//打印二维码
/**
 *
 *
 * @export
 * @param {object} options
 * {
            deviceId,
            serviceId,
            characteristicId,
            value,//ArrayBuffer:二维码的数据
    }
 */
export function printQR(options) {
    //打印二维码的十进制指令data：
    let data = [...printCommand.clear, 29, 107, 97, 7, 4, options.value.byteLength, 0];
    sendDataToDevice({
        ...options,
        value: new Uint8Array(data).buffer,
        lasterSuccess: () => {
            //指令发送成功后，发送二维码的数据
            sendDataToDevice(options);
        },
    });
}

function grayPixle(pix) {
    return pix[0] * 0.299 + pix[1] * 0.587 + pix[2] * 0.114;
}
/**
 * overwriteImageData 图片数据转 位图数据
 * @param {object} data
 * {
            width,//图片宽度
            height,//图片高度
            imageData,//Uint8ClampedArray
            threshold,//阈值, 越大，打印点数越多，图形越黑
    }
 */
export function overwriteImageData(data) {
    let sendWidth = data.width,
        sendHeight = data.height;
    const threshold = data.threshold || 180;
    let sendImageData = new ArrayBuffer((sendWidth * sendHeight) / 8);
    sendImageData = new Uint8Array(sendImageData);
    let pix = data.imageData;
    const part = [];
    let index = 0;
    for (let i = 0; i < pix.length; i += 32) {
        //横向每8个像素点组成一个字节（8位二进制数）。
        for (let k = 0; k < 8; k++) {
            const grayPixle1 = grayPixle(pix.slice(i + k * 4, i + k * 4 + (4 - 1)));
            //阈值调整
            if (grayPixle1 > threshold) {
                //灰度值大于128位   白色 为第k位0不打印
                part[k] = 0;
            } else {
                part[k] = 1;
            }
        }
        let temp = 0;
        for (let a = 0; a < part.length; a++) {
            temp += part[a] * Math.pow(2, part.length - 1 - a);
        }
        //开始不明白以下算法什么意思，了解了字节才知道，一个字节是8位的二进制数，part这个数组存的0和1就是二进制的0和1，传输到打印的位图数据的一个字节是0-255之间的十进制数，以下是用相权相加法转十进制数，理解了这个就用上面的for循环替代了
        // const temp =
        //   part[0] * 128 +
        //   part[1] * 64 +
        //   part[2] * 32 +
        //   part[3] * 16 +
        //   part[4] * 8 +
        //   part[5] * 4 +
        //   part[6] * 2 +
        //   part[7] * 1;
        sendImageData[index++] = temp;
    }
    return {
        array: Array.from(sendImageData),
        width: sendWidth / 8,
        height: sendHeight,
    };
}
/**
 * 分段发送二进制数据，按allUint8Array的length产生发送的进度
 * @export
 * @param {object} options
 * {
            deviceId,
            serviceId,
            characteristicId,
			lasterSuccess,
            onProgress,
    }
 *  * @param {array} allUint8Array  所有的Uint8Array
 */
export function sendDataToPrint(options, allUint8Array) {
    const allLenth = allUint8Array.length;
	console.log("sendDataToPrint:allLenth=======", allLenth)
	console.log("sendDataToPrint:allUint8Array-len=======", allUint8Array.length)
    const writeArrayCopyer = allUint8Array.slice(0);
    const print = (options, writeArray) => {
		console.log("===writeArray.length===", writeArray.length)
        if (writeArray.length) {
			let curBuffer = writeArray.shift().buffer
            sendDataToDevice({
                ...options,
                value: curBuffer,
                lasterSuccess: () => {
                    options.onProgress &&
                        options.onProgress(Math.floor(((allLenth - writeArray.length) / allLenth) * 100));
                    if (writeArray.length) {
                        print(options, writeArray);
                    } else {
                        options.lasterSuccess && options.lasterSuccess();
                    }
                },
            });
        }
    };
    print(options, writeArrayCopyer);
}
/**
 * 获取打印图片的指令
 *
 * @export
 * @param {object} options
 * {
           lineByLine, // 是否逐行打印，默认true
    }
  * @param {object} imageInfo overwriteImageData 得到的位图数据数组和宽高信息
    {
        array,
        width,
        height
    }
 */
export function getImageCommandArray(opt = {}, imageInfo = {}) {
    const lineByLine = typeof opt.lineByLine !== 'boolean' ? true : opt.lineByLine;
    const width = imageInfo.width;
    const h = imageInfo.height;
    const xl = width % 256;
    const xh = (width - xl) / 256;
    const yl = h % 256;
    const yh = (h - yl) / 256;
    //打印图片的十进制指令数组
    let command = [];

    if (lineByLine) {
        // 分段逐行的指令
        command = command.concat([29, 118, 48, 0, xl, xh, 1, 0]);
    } else {
        // 非分段逐行的指令
        command = command.concat([29, 118, 48, 0, xl, xh, yl, yh]);
    }

    return command;
}
/**
 * 获取一张图片数据与指令整合的writeArray，结合 sendDataToPrint 发送二进制数据到蓝牙打印机
 * @param {object} options
 * {
           lineByLine, // 是否逐行打印，默认true
           printAlign, // 打印的位置
    }
  * @param {object} imageInfo overwriteImageData 得到的位图数据数组和宽高信息
    {
        array,
        width,
        height
    }
 */
export function getPrintImageWriteArray(opt = {}, imageInfo = {}) {
    const lineByLine = typeof opt.lineByLine !== 'boolean' ? true : opt.lineByLine;
    const width = imageInfo.width;
    let arr = imageInfo.array;
    let writeArray = [];
    const iniTcommand = [].concat(printCommand.clear).concat(printCommand[opt.printAlign || 'left']);
    const command = getImageCommandArray(opt, imageInfo);
    writeArray.push(new Uint8Array(iniTcommand));
    // 分段逐行打印的数据
    if (lineByLine) {
        for (let i = 0; i < arr.length / width; i++) {
            const subArr = arr.slice(i * width, i * width + width);
            const tempArr = command.concat(subArr);
            writeArray.push(new Uint8Array(tempArr));
        }
    } else {
        // 非逐行打印
        writeArray.push(new Uint8Array(command.concat(arr)));
    }
    // writeArray.push(new Uint8Array([27, 74, 3]));
    return writeArray;
}
/**
 * 只打印一张图片数据的方法
 * @param {object} options
 * {
            deviceId,
            serviceId,
            characteristicId,
			lasterSuccess,
            onProgress,
            printAlign, "left"|"right"|"center" 
    }
 * @param {object} imageInfo overwriteImageData 得到的位图数据数组和宽高信息
    {
        array,
        width,
        height
    }
 */

export function printImage(opt, imageInfo) {
    sendDataToPrint(
        opt,
        getPrintImageWriteArray(
            {
                printAlign: opt.printAlign,
                lineByLine: opt.lineByLine,
            },
            imageInfo,
        ),
    );
}