Python使用Twain协议调用扫描仪

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Python使用Twain协议调用扫描仪

安装

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pip install pytwain
pip install Pillow

官方方式

注意

调用扫描要在主进程中执行，否则无法获取扫描的回调。

测试

这种方式会在32位的Python下加载twain_32.dll，在64位的Python下加载twaindsm.dll，在32和64位下均能正常运行。

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import logging
import os
import tkinter
from datetime import datetime
from io import BytesIO
from tkinter import ttk

import PIL.Image
import PIL.ImageTk
import twain
from twain.lowlevel import constants


def select():
    with twain.SourceManager(root) as sm:
        src = sm.open_source()
        if src:
            scanner_name = src.name
            print(f"选择的扫描仪名称是: {scanner_name}")
        else:
            print("未选择任何扫描仪。")


def scan():
    show_ui = False
    dpi = 200
    scan_num = 1
    with twain.SourceManager(root) as sm:
        sd = sm.open_source("HUAGOSCAN G200 TWAIN")
        more = 1
        if sd:
            if dpi:
                sd.set_capability(
                    constants.ICAP_XRESOLUTION,
                    constants.TWTY_FIX32, dpi)
                sd.set_capability(
                    constants.ICAP_YRESOLUTION,
                    constants.TWTY_FIX32, dpi)
            sd.request_acquire(show_ui=show_ui, modal_ui=True)
            sd.modal_loop()
            while more:
                (handle, has_more) = sd.xfer_image_natively()
                more = has_more
                print(f"has_more:{has_more}")
                bmp_bytes = twain.dib_to_bm_file(handle)
                img = PIL.Image.open(BytesIO(bmp_bytes), formats=["bmp"])
                timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
                file_name = f"imgs/scan_{timestamp}_{scan_num:03d}.jpg"
                img.save(file_name, format='jpeg')
                scan_num += 1
        else:
            print("User clicked cancel")


logging.basicConfig(level=logging.INFO)
root = tkinter.Tk()
frm = ttk.Frame(root, padding=10)
frm.grid()
ttk.Button(frm, text="选择扫描仪", command=select).grid(column=0, row=0)
ttk.Button(frm, text="开始扫描", command=scan).grid(column=0, row=1)

if not os.path.exists("imgs"):
    os.makedirs("imgs")
root.mainloop()

工具类

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# This Python file uses the following encoding: utf-8
import os
from datetime import datetime
from io import BytesIO
from typing import Callable, List, Optional

import PIL.Image
import PIL.ImageTk
import twain
from twain.lowlevel import constants

from common.global_vars import GlobalVars


def scan_paper(
    save_folder: str,
    show_ui: bool = False,
    dsm_name: Optional[str] = None,
    dpi: float = 200,
    duplex: bool = True,  # 是否为双面扫描
    on_scan_img: Optional[Callable[[str], None]] = None,
    on_scan_finish: Optional[Callable[[], None]] = None,
    on_scan_error: Optional[Callable[[Exception], None]] = None,
):
    print(
        f"save_folder:{save_folder} show_ui:{show_ui} dsm_name:{dsm_name} dpi:{dpi}")
    hwnd = GlobalVars.root_window.winId()

    with twain.SourceManager(hwnd) as sm:
        sd = sm.open_source(dsm_name)
        scan_page_num = 1
        more = 1
        if sd:
            if dpi:
                sd.set_capability(
                    constants.ICAP_XRESOLUTION,
                    constants.TWTY_FIX32, dpi)
                sd.set_capability(
                    constants.ICAP_YRESOLUTION,
                    constants.TWTY_FIX32, dpi)
            # 双面扫描
            sd.set_capability(
                constants.CAP_DUPLEXENABLED,
                constants.TWTY_BOOL, duplex)

            sd.request_acquire(show_ui=show_ui, modal_ui=True)
            sd.modal_loop()

            try:
                while more:
                    (handle, has_more) = sd.xfer_image_natively()
                    more = has_more

                    bmp_bytes = twain.dib_to_bm_file(handle)
                    img = PIL.Image.open(BytesIO(bmp_bytes), formats=["bmp"])
                    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
                    file_name = f"scan_{timestamp}_{scan_page_num:03d}.jpg"
                    full_path = os.path.join(save_folder, file_name)
                    print(f"full_path:{full_path}")
                    if not duplex or scan_page_num % 2 == 1:
                        img.save(full_path, format='jpeg')
                    else:
                        rotated_img = img.rotate(180)
                        rotated_img.save(full_path, format='jpeg')

                    if on_scan_img is not None:
                        on_scan_img(full_path)
                    scan_page_num += 1
                if on_scan_finish is not None:
                    on_scan_finish()
            except twain.exceptions.DSTransferCancelled:
                # 捕获用户取消扫描的异常
                print("User cancelled the scan.")
                if on_scan_error is not None:
                    on_scan_error(Exception("用户取消"))

            except Exception as e:
                if on_scan_error is not None:
                    on_scan_error(e)
        else:
            if on_scan_error is not None:
                on_scan_error(Exception("用户取消"))


def select_device() -> List[str]:
    hwnd = GlobalVars.root_window.winId()
    name_arr = []
    sm = None
    try:
        sm = twain.SourceManager(hwnd)
        s_list = sm.GetSourceList()
        for idx, name in enumerate(s_list):
            name_arr.append(name)
    finally:
        if sm is not None:
            sm.close()
    return name_arr

Qt Quick中传入parent_window

twain.SourceManager要传入parent_window，但是源码中是这样判断的

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self._hwnd = 0
if utils.is_windows():
  if hasattr(parent_window, "winfo_id"):
    # tk window
    self._hwnd = parent_window.winfo_id()
  elif hasattr(parent_window, "GetHandle"):
    # wx window
    self._hwnd = parent_window.GetHandle()
  elif hasattr(parent_window, "window") and hasattr(
    parent_window.window, "handle"
  ):
    # gtk window
    self._hwnd = parent_window.window.handle
  elif parent_window is None:
    self._hwnd = 0
  else:
    self._hwnd = int(parent_window)

可以看到如果我们的窗口是Tk, Wx or Gtk window，则是没问题的

但是Qt的窗口是PySide2.QtQuick.QQuickWindow

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root_window = engine.rootObjects()[0]

所以直接传窗口对象是不行的

可以传入句柄

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root_window = engine.rootObjects()[0]
hwnd = root_window.winId()

使用TWAINDSM

这种方式我在Qt Quick中如果Python是64位是没问题的，但是32位的时候就不行

扫描测试

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# This Python file uses the following encoding: utf-8

import json
import os
from datetime import datetime
from typing import Callable, Dict, List, Literal, Optional, Tuple

import twain
from twain import exceptions
from twain.lowlevel import constants

from utils.z_sys_utils import get_sys_bit
from utils.zlog import logger


def acquire(
        save_folder: str,
        dpi: Optional[float] = None,
        pixel_type: Optional[Literal["bw", "gray", "color"]] = "color",
        bpp: Optional[int] = None,
        frame: Optional[Tuple[float, float, float, float]] = None,
        show_ui: bool = False,
        dsm_name: Optional[str] = None,
        modal: bool = True,
        on_scan_img: Optional[Callable[[str], None]] = None,
        on_scan_finish: Optional[Callable[[], None]] = None,
        on_scan_error: Optional[Callable[[Exception], None]] = None,
) -> Optional[List[Dict]]:
    sysbit = get_sys_bit()
    logger.info(
        f"开始acquire函数,参数: path={save_folder}, dpi={dpi}, pixel_type={pixel_type}, frame={frame}")
    if pixel_type:
        pixel_type_map = {
            "bw": constants.TWPT_BW,
            "gray": constants.TWPT_GRAY,
            "color": constants.TWPT_RGB,
        }
        twain_pixel_type = pixel_type_map[pixel_type]
        logger.info(f"设置像素类型: {pixel_type}")
    else:
        twain_pixel_type = None
    logger.info(f"使用扫描仪: {dsm_name}")
    sm = twain.SourceManager(0, dsm_name=f"dll\\twain\\{sysbit}\\TWAINDSM.dll")
    logger.info("创建SourceManager对象")
    page_number = 0
    full_path = ""
    try:
        sd = sm.open_source(dsm_name)
        if not sd:
            logger.error("无法打开数据源")
            if on_scan_error is not None:
                on_scan_error(Exception("无法打开扫描仪"))
            return None
        logger.info("成功打开数据源")
        try:
            if twain_pixel_type:
                sd.set_capability(
                    constants.ICAP_PIXELTYPE,
                    constants.TWTY_UINT16, twain_pixel_type)
            sd.set_capability(
                constants.ICAP_UNITS,
                constants.TWTY_UINT16, constants.TWUN_INCHES)
            # 是否双面打印
            sd.set_capability(
                constants.CAP_DUPLEXENABLED,
                constants.TWTY_BOOL, True)
            if bpp:
                sd.set_capability(
                    constants.ICAP_BITDEPTH,
                    constants.TWTY_UINT16, bpp)
            if dpi:
                sd.set_capability(
                    constants.ICAP_XRESOLUTION,
                    constants.TWTY_FIX32, dpi)
                sd.set_capability(
                    constants.ICAP_YRESOLUTION,
                    constants.TWTY_FIX32, dpi)
            if frame:
                try:
                    sd.set_image_layout(frame)
                except exceptions.CheckStatus:
                    logger.warning("设置图像布局失败")
            logger.info("设置扫描参数完成")
            res: List[Dict] = []

            def before(img_info: Dict) -> str:
                nonlocal page_number
                nonlocal full_path
                page_number += 1
                timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
                file_name = f"scan_{timestamp}_{page_number:03d}.png"
                full_path = os.path.join(save_folder, file_name)
                res.append(img_info)
                logger.info(f"准备保存第 {page_number} 页,文件路径: {full_path}")
                return full_path

            def after(more: int) -> None:
                logger.info(f"保存完毕-第 {page_number} 页,文件路径: {full_path}")
                if os.path.exists(full_path):
                    if on_scan_img is not None:
                        on_scan_img(full_path)
                if more == 0:
                    logger.info("扫描完成,没有更多页面")

            try:
                sd.acquire_file(before=before, after=after,
                                show_ui=show_ui, modal=modal)
                logger.info("扫描结束")
                if on_scan_finish is not None:
                    on_scan_finish()
            except Exception as e:
                logger.info("用户取消了扫描:"+str(e))
                if on_scan_error is not None:
                    on_scan_error(e)
                return None
        finally:
            sd.close()
            logger.info("关闭数据源")
    except Exception as e:
        on_scan_error(e)
    finally:
        sm.close()
        logger.info("关闭SourceManager")
    logger.info(f"扫描结果: {json.dumps(res)}")
    return res


def select_device() -> List[str]:
    sysbit = get_sys_bit()
    name_arr = []
    sm = None
    try:
        sm = twain.SourceManager(
            0, dsm_name=f"dll\\twain\\{sysbit}\\TWAINDSM.dll")
        s_list = sm.GetSourceList()
        for idx, name in enumerate(s_list):
            name_arr.append(name)
    finally:
        if sm is not None:
            sm.close()
    return name_arr

测试

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output_directory = r"D:\test"
if not os.path.exists(output_directory):
    os.makedirs(output_directory)
    logger.info(f"创建输出目录: {output_directory}")


def scan():
    logger.info("开始扫描过程")
    try:
        outpath = output_directory
        logger.info(f"输出路径: {outpath}")
        dsm_name = "HUAGOSCAN G200 TWAIN"
        result = acquire(
            outpath,
            dsm_name=dsm_name,
            dpi=200,
            pixel_type="color",
            show_ui=False,
        )
    except Exception as e:
        logger.error(f"扫描过程中发生错误: {str(e)}")
    else:
        if result:
            logger.info(f"扫描成功,图像保存在: {outpath}")

驱动无法调用

这种情况可能是TWAINDSM.dll的位数不匹配。

twain-dsm-2.5.1.zip
https://pan.baidu.com/s/1kM7Pbvzh2QVQyKlAnTNxSA?pwd=w7id

我这里DLL放在项目根目录下的dll\twain\32\TWAINDSM.dll

根据程序是32位还是64位选择性加载即可。

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sm = twain.SourceManager(0, dsm_name=r"dll\twain\32\TWAINDSM.dll")

打包时

添加项目下dll

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pyinstaller main.py -y --noconsole --name="xhscanner-client" --icon="logo.ico" --add-binary "dll\twain\32\TWAINDSM.dll;."

上面这种方式TWAINDSM.dll会放在_internal目录中，这样虽然路径变了，但是_internal根路径的DLL因为可以正常加载，所以可以正常使用。

获取Python位数

这是获取Python运行环境的位数，也就是我们程序的位数，不是系统的位数。

z_sys_utils.py

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import sys


def get_sys_bit():
    if sys.maxsize == 2**31 - 1:
        return 32
    elif sys.maxsize == 2**63 - 1:
        return 64
    else:
        return 32

完整示例

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import logging
import os
import tkinter
from datetime import datetime
from io import BytesIO
from tkinter import ttk

import PIL.Image
import PIL.ImageTk
import twain
from twain.lowlevel import constants


def select():
    with twain.SourceManager(root) as sm:
        src = sm.open_source()
        if src:
            scanner_name = src.name
            print(f"选择的扫描仪名称是: {scanner_name}")
        else:
            print("未选择任何扫描仪。")


def scan():
    show_ui = False
    sanner_source_name = "HUAGOSCAN G200 TWAIN"
    dpi = 200
    scan_num = 1
    with twain.SourceManager(root) as sm:
        sd = sm.open_source(sanner_source_name)
        more = 1
        if sd:
            if dpi:
                sd.set_capability(
                    constants.ICAP_XRESOLUTION,
                    constants.TWTY_FIX32, dpi)
                sd.set_capability(
                    constants.ICAP_YRESOLUTION,
                    constants.TWTY_FIX32, dpi)
            # 是否双面打印
            sd.set_capability(
                constants.CAP_DUPLEXENABLED,
                constants.TWTY_BOOL, True)
            sd.request_acquire(show_ui=show_ui, modal_ui=True)
            while more:
                (handle, has_more) = sd.xfer_image_natively()
                more = has_more
                print(f"has_more:{has_more}")
                bmp_bytes = twain.dib_to_bm_file(handle)
                img = PIL.Image.open(BytesIO(bmp_bytes), formats=["bmp"])
                timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
                file_name = f"imgs/scan_{timestamp}_{scan_num:03d}.jpg"
                img.save(file_name, format='jpeg')
                scan_num += 1
        else:
            print("User clicked cancel")


logging.basicConfig(level=logging.INFO)
root = tkinter.Tk()
frm = ttk.Frame(root, padding=10)
frm.grid()
ttk.Button(frm, text="选择扫描仪", command=select).grid(column=0, row=0)
ttk.Button(frm, text="开始扫描", command=scan).grid(column=0, row=1)

if not os.path.exists("imgs"):
    os.makedirs("imgs")
root.mainloop()