#!/usr/bin/env python 
# -*- coding:utf-8 -*-

# 1.接口文档（必看）：https://www.xfyun.cn/doc/words/formula-discern/API.html
# 2.错误码链接：https://www.xfyun.cn/document/error-code （错误码code为5位数字）
#

import requests
import datetime
import hashlib
import base64
import hmac
import json


class FormulaRecognition(object):
    def __init__(self):
        # 应用ID（到控制台获取）
        self.APPID = ""
        # 接口APISercet（到控制台公式识别服务页面获取）
        self.Secret = ""
        # 接口APIKey（到控制台公式识别服务页面获取）
        self.APIKey = ""

        # 以下为POST请求
        self.Host = "rest-api.xfyun.cn"
        self.RequestUri = "/v2/itr"
        # 设置url
        # print(host)
        self.url = "https://" + self.Host + self.RequestUri
        self.HttpMethod = "POST"
        self.Algorithm = "hmac-sha256"
        self.HttpProto = "HTTP/1.1"

        # 设置当前时间
        curTime_utc = datetime.datetime.utcnow()
        self.Date = self.httpdate(curTime_utc)
        self.BusinessArgs = {
            "ent": "teach-photo-print",
            "aue": "raw",
        }

    def imgRead(self, path):
        with open(path, 'rb') as fo:
            return fo.read()

    def hashlib_256(self, res):
        m = hashlib.sha256(bytes(res.encode(encoding='utf-8'))).digest()
        result = "SHA-256=" + base64.b64encode(m).decode(encoding='utf-8')
        return result

    def httpdate(self, dt):
        """
        Return a string representation of a date according to RFC 1123
        (HTTP/1.1).

        The supplied date must be in UTC.

        """
        weekday = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"][dt.weekday()]
        month = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep",
                 "Oct", "Nov", "Dec"][dt.month - 1]
        return "%s, %02d %s %04d %02d:%02d:%02d GMT" % (weekday, dt.day, month,
                                                        dt.year, dt.hour, dt.minute, dt.second)

    def generateSignature(self, digest):
        signatureStr = "host: " + self.Host + "\n"
        signatureStr += "date: " + self.Date + "\n"
        signatureStr += self.HttpMethod + " " + self.RequestUri \
                        + " " + self.HttpProto + "\n"
        signatureStr += "digest: " + digest
        signature = hmac.new(bytes(self.Secret.encode(encoding='utf-8')),
                             bytes(signatureStr.encode(encoding='utf-8')),
                             digestmod=hashlib.sha256).digest()
        result = base64.b64encode(signature)
        return result.decode(encoding='utf-8')

    def init_header(self, data):
        digest = self.hashlib_256(data)
        # print(digest)
        sign = self.generateSignature(digest)
        authHeader = 'api_key="%s", algorithm="%s", ' \
                     'headers="host date request-line digest", ' \
                     'signature="%s"' \
                     % (self.APIKey, self.Algorithm, sign)
        # print(authHeader)
        headers = {
            "Content-Type": "application/json",
            "Accept": "application/json",
            "Method": "POST",
            "Host": self.Host,
            "Date": self.Date,
            "Digest": digest,
            "Authorization": authHeader
        }
        return headers

    def get_body(self, image_path):
        audioData = self.imgRead(image_path)
        content = base64.b64encode(audioData).decode(encoding='utf-8')
        postdata = {
            "common": {"app_id": self.APPID},
            "business": self.BusinessArgs,
            "data": {
                "image": content,
            }
        }
        body = json.dumps(postdata)
        # print(body)
        return body

    def call_url(self, image_path):
        if self.APPID == '' or self.APIKey == '' or self.Secret == '':
            print('Appid 或APIKey 或APISecret 为空！请打开demo代码，填写相关信息。')
        else:
            code = 0
            body = self.get_body(image_path)
            headers = self.init_header(body)
            # print(self.url)
            response = requests.post(self.url, data=body, headers=headers, timeout=8)
            status_code = response.status_code
            # print(response.content)
            if status_code != 200:
                # 鉴权失败
                print("Http请求失败，状态码：" + str(status_code) + "，错误信息：" + response.text)
                print("请根据错误信息检查代码，接口文档：https://www.xfyun.cn/doc/words/formula-discern/API.html")
            else:
                # 鉴权成功
                respData = json.loads(response.text)
                # print(respData)
                # 以下仅用于调试
                code = str(respData["code"])
                if code != '0':
                    print("请前往https://www.xfyun.cn/document/error-code?code=" + code + "查询解决办法")
            return response.json()

if __name__ == '__main__':
    gClass = FormulaRecognition()
    gClass.call_url('01.png')

测试图片：

实现截图示例代码

先导入库

import re
import time
import pyperclip
from PIL import Image, ImageGrab
import os
from formulaRecognition import FormulaRecognition
import ctypes

截图功能可以简单地直接使用“旧版的QQ、微信的dll”来实现，相比之下，微信的dll更好用点。Python中可以使用ctypes来调用dll，但可能会遇到一些问题，详见：

Python调用动态链接库DLL文件_小锋学长生活大爆炸的博客-CSDN博客简单用用dll

由于本机python为64位，dll为32位，因此这里使用rundll32来实现，如下：

os.system('RUNDLL32.EXE PrScrn.dll PrScrn')

为了在截图时候隐藏当前的窗口，可以使用如下方式：

window_handle = ctypes.windll.kernel32.GetConsoleWindow()
# 0：隐藏；6：最小化
# 1：显示；3：最大化
ctypes.windll.user32.ShowWindow(window_handle, 0)
time.sleep(0.5)
os.system('RUNDLL32.EXE PrScrn.dll PrScrn')
ctypes.windll.user32.ShowWindow(window_handle, 1)

微信dll截图后的图片存放在剪切板，因此需要从剪切板上读取后，再使用讯飞API来识别，由于pyperclip只支持文字，因此对于图片类的，需要使用PIL库。如下：

img = ImageGrab.grabclipboard()
if not isinstance(img, Image.Image):
    return
print('>> 识别中...')
image_path = "formula_recognition_temp.png"
img.save(image_path)
recognition = FormulaRecognition()
res = recognition.call_url(image_path)
os.remove(image_path)
if res['code'] != 0:
    return
content = res['data']['region'][0]['recog']['content']
content = re.sub(r'ifly-latex-begin', '', content)
content = re.sub(r'ifly-latex-end', '', content)
# 将结果复制到剪切板
pyperclip.copy(content)
print(content)

最终代码与效果

import re
import time
import pyperclip
from PIL import Image, ImageGrab
import os
from formulaRecognition import FormulaRecognition
import ctypes



def start():
    window_handle = ctypes.windll.kernel32.GetConsoleWindow()
    # 0：隐藏；6：最小化
    # 1：显示；3：最大化
    ctypes.windll.user32.ShowWindow(window_handle, 0)
    time.sleep(0.5)
    os.system('RUNDLL32.EXE PrScrn.dll PrScrn')
    ctypes.windll.user32.ShowWindow(window_handle, 1)
    img = ImageGrab.grabclipboard()
    if not isinstance(img, Image.Image):
        return
    print('>> 识别中...')
    image_path = "formula_recognition_temp.png"
    img.save(image_path)
    recognition = FormulaRecognition()
    res = recognition.call_url(image_path)
    os.remove(image_path)
    if res['code'] != 0:
        return
    content = res['data']['region'][0]['recog']['content']
    content = re.sub(r'ifly-latex-begin', '', content)
    content = re.sub(r'ifly-latex-end', '', content)
    # 将结果复制到剪切板
    pyperclip.copy(content)
    print(content)


if __name__ == '__main__':
    while True:
        if input('>> 按回车启动，按q退出: ').strip().lower() == 'q':
            break
        print('>> 启动中...')
        try:
            start()
        except Exception as e:
            print(e)

运行中：

识别结果：

\frac {c}{a}    \sin   A=  \frac {bc}{a^ {2}}    \sin ^ {2}  A=  \frac {20}{21}    \times     \frac {3}{4}  =  \frac {5}{7}

放入markdown看下效果：

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原始发表：2022-04-17，如有侵权请联系 cloudcommunity@tencent.com 删除

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