建立 Python 相機 SDK 並使用它進行多條碼掃描

現在輕量C 相機SDK 已經完成，適用於Windows、Linux 和macOS，我們可以將其整合到其他高階程式語言中。在本文中，我們將探討如何基於 C 相機庫建立 Python 相機 SDK，並使用它與 Dynamsoft Barcode Reader SDK 進行多條碼掃描。

Python 多條碼掃描器演示視頻

搭建 CPython 擴充項目的鷹架

CPython 擴充功能是一個共享函式庫（例如，Windows 上的DLL、Linux 上的.so 或macOS 上的.dylib）可以在執行時載入到Python解釋器中並用於擴展其功能。 lite相機CPython擴充專案的結構如下：

python-lite-camera
│
│── include
│   ├── Camera.h
│   ├── CameraPreview.h
│   ├── stb_image_write.h
│── lib
│   ├── linux
│   │   ├── liblitecam.so
│   ├── macos
│   │   ├── liblitecam.dylib
│   ├── windows
│   │   ├── litecam.dll
│   │   ├── litecam.lib
├── src
│   ├── litecam.cpp
│   ├── pycamera.h
│   ├── pywindow.h
│── litecam
│   ├── __init__.py
│── setup.py
│── MANIFEST.in
│── README.md

說明：

• include：C相機庫的頭檔。
• lib：C 相機庫的共享庫。
• src：Python相機SDK的原始碼。
• litecam：Python 擴充的入口點。
• setup.py：建置腳本。
• MANIFEST.in：包含非Python檔案的清單檔案。
• README.md：文件。

為 Python 擴充功能編寫建置腳本 setup.py

在setup.py中加入以下內容：

from setuptools.command import build_ext
from setuptools import setup, Extension
import sys
import os
import io
from setuptools.command.install import install
import shutil
from pathlib import Path

lib_dir = ''

sources = [
    "src/litecam.cpp",
]

include_dirs = [os.path.join(os.path.dirname(__file__), "include")]

libraries = ['litecam']

extra_compile_args = []

if sys.platform == "linux" or sys.platform == "linux2":
    lib_dir = 'lib/linux'
    extra_compile_args = ['-std=c++11']
    extra_link_args = ["-Wl,-rpath=$ORIGIN"]
elif sys.platform == "darwin":
    lib_dir = 'lib/macos'
    extra_compile_args = ['-std=c++11']
    extra_link_args = ["-Wl,-rpath,@loader_path"]
elif sys.platform == "win32":
    lib_dir = 'lib/windows'
    extra_link_args = []

else:
    raise RuntimeError("Unsupported platform")


long_description = io.open("README.md", encoding="utf-8").read()

module_litecam = Extension(
    "litecam",
    sources=sources,
    include_dirs=include_dirs,
    library_dirs=[lib_dir],
    libraries=libraries,
    extra_compile_args=extra_compile_args,
    extra_link_args=extra_link_args,
)

def copyfiles(src, dst):
    if os.path.isdir(src):
        filelist = os.listdir(src)
        for file in filelist:
            libpath = os.path.join(src, file)
            shutil.copy2(libpath, dst)
    else:
        shutil.copy2(src, dst)


class CustomBuildExt(build_ext.build_ext):
    def run(self):
        build_ext.build_ext.run(self)
        dst = os.path.join(self.build_lib, "litecam")
        copyfiles(lib_dir, dst)
        filelist = os.listdir(self.build_lib)
        for file in filelist:
            filePath = os.path.join(self.build_lib, file)
            if not os.path.isdir(file):
                copyfiles(filePath, dst)
                os.remove(filePath)


class CustomBuildExtDev(build_ext.build_ext):
    def run(self):
        build_ext.build_ext.run(self)
        dev_folder = os.path.join(Path(__file__).parent, 'litecam')
        copyfiles(lib_dir, dev_folder)
        filelist = os.listdir(self.build_lib)
        for file in filelist:
            filePath = os.path.join(self.build_lib, file)
            if not os.path.isdir(file):
                copyfiles(filePath, dev_folder)


class CustomInstall(install):
    def run(self):
        install.run(self)


setup(name='lite-camera',
      version='2.0.1',
      description='LiteCam is a lightweight, cross-platform library for capturing RGB frames from cameras and displaying them. Designed with simplicity and ease of integration in mind, LiteCam supports Windows, Linux and macOS platforms.',
      long_description=long_description,
      long_description_content_type="text/markdown",
      author='yushulx',
      url='https://github.com/yushulx/python-lite-camera',
      license='MIT',
      packages=['litecam'],
      ext_modules=[module_litecam],
      classifiers=[
           "Development Status :: 5 - Production/Stable",
           "Environment :: Console",
           "Intended Audience :: Developers",
          "Intended Audience :: Education",
          "Intended Audience :: Information Technology",
          "Intended Audience :: Science/Research",
          "License :: OSI Approved :: MIT License",
          "Operating System :: Microsoft :: Windows",
          "Operating System :: MacOS",
          "Operating System :: POSIX :: Linux",
          "Programming Language :: Python",
          "Programming Language :: Python :: 3",
          "Programming Language :: Python :: 3 :: Only",
          "Programming Language :: Python :: 3.6",
          "Programming Language :: Python :: 3.7",
          "Programming Language :: Python :: 3.8",
          "Programming Language :: Python :: 3.9",
          "Programming Language :: Python :: 3.10",
          "Programming Language :: Python :: 3.11",
          "Programming Language :: Python :: 3.12",
          "Programming Language :: C++",
          "Programming Language :: Python :: Implementation :: CPython",
          "Topic :: Scientific/Engineering",
          "Topic :: Software Development",
      ],
      cmdclass={
          'install': CustomInstall,
          'build_ext': CustomBuildExt,
          'develop': CustomBuildExtDev},
      )

說明：

• lite-camera：Python 套件的名稱。
• ext_modules：CPython 擴充列表。它指定不同平台的原始檔、包含目錄、函式庫目錄、函式庫以及編譯/連結標誌。
• 開發：用於開發的自訂命令。它將共用庫複製到 litecam 資料夾以方便測試。
• build_ext：自訂建置流程，將共用程式庫打包到wheel套件中。

用 C 語言實作 Python Camera SDK API

pycamera.h 檔案定義了用於從相機捕獲幀的 PyCamera Python 類，而 pywindow.h 檔案定義了用於在視窗中顯示幀的 PyWindow Python 類。 litecam.cpp 檔案作為 Python 擴充功能的入口點，其中定義了一些全域方法，並註冊了 PyCamera 和 PyWindow 類別。

pycamera.h

包括

python-lite-camera
│
│── include
│   ├── Camera.h
│   ├── CameraPreview.h
│   ├── stb_image_write.h
│── lib
│   ├── linux
│   │   ├── liblitecam.so
│   ├── macos
│   │   ├── liblitecam.dylib
│   ├── windows
│   │   ├── litecam.dll
│   │   ├── litecam.lib
├── src
│   ├── litecam.cpp
│   ├── pycamera.h
│   ├── pywindow.h
│── litecam
│   ├── __init__.py
│── setup.py
│── MANIFEST.in
│── README.md

• Python.h：包含使用 Python C API。
• structmember.h：提供用於管理物件成員的巨集和幫助器。
• Camera.h：定義 Camera 類，PyCamera 擴充對其進行包裝。

PyCamera 結構體定義

from setuptools.command import build_ext
from setuptools import setup, Extension
import sys
import os
import io
from setuptools.command.install import install
import shutil
from pathlib import Path

lib_dir = ''

sources = [
    "src/litecam.cpp",
]

include_dirs = [os.path.join(os.path.dirname(__file__), "include")]

libraries = ['litecam']

extra_compile_args = []

if sys.platform == "linux" or sys.platform == "linux2":
    lib_dir = 'lib/linux'
    extra_compile_args = ['-std=c++11']
    extra_link_args = ["-Wl,-rpath=$ORIGIN"]
elif sys.platform == "darwin":
    lib_dir = 'lib/macos'
    extra_compile_args = ['-std=c++11']
    extra_link_args = ["-Wl,-rpath,@loader_path"]
elif sys.platform == "win32":
    lib_dir = 'lib/windows'
    extra_link_args = []

else:
    raise RuntimeError("Unsupported platform")


long_description = io.open("README.md", encoding="utf-8").read()

module_litecam = Extension(
    "litecam",
    sources=sources,
    include_dirs=include_dirs,
    library_dirs=[lib_dir],
    libraries=libraries,
    extra_compile_args=extra_compile_args,
    extra_link_args=extra_link_args,
)

def copyfiles(src, dst):
    if os.path.isdir(src):
        filelist = os.listdir(src)
        for file in filelist:
            libpath = os.path.join(src, file)
            shutil.copy2(libpath, dst)
    else:
        shutil.copy2(src, dst)


class CustomBuildExt(build_ext.build_ext):
    def run(self):
        build_ext.build_ext.run(self)
        dst = os.path.join(self.build_lib, "litecam")
        copyfiles(lib_dir, dst)
        filelist = os.listdir(self.build_lib)
        for file in filelist:
            filePath = os.path.join(self.build_lib, file)
            if not os.path.isdir(file):
                copyfiles(filePath, dst)
                os.remove(filePath)


class CustomBuildExtDev(build_ext.build_ext):
    def run(self):
        build_ext.build_ext.run(self)
        dev_folder = os.path.join(Path(__file__).parent, 'litecam')
        copyfiles(lib_dir, dev_folder)
        filelist = os.listdir(self.build_lib)
        for file in filelist:
            filePath = os.path.join(self.build_lib, file)
            if not os.path.isdir(file):
                copyfiles(filePath, dev_folder)


class CustomInstall(install):
    def run(self):
        install.run(self)


setup(name='lite-camera',
      version='2.0.1',
      description='LiteCam is a lightweight, cross-platform library for capturing RGB frames from cameras and displaying them. Designed with simplicity and ease of integration in mind, LiteCam supports Windows, Linux and macOS platforms.',
      long_description=long_description,
      long_description_content_type="text/markdown",
      author='yushulx',
      url='https://github.com/yushulx/python-lite-camera',
      license='MIT',
      packages=['litecam'],
      ext_modules=[module_litecam],
      classifiers=[
           "Development Status :: 5 - Production/Stable",
           "Environment :: Console",
           "Intended Audience :: Developers",
          "Intended Audience :: Education",
          "Intended Audience :: Information Technology",
          "Intended Audience :: Science/Research",
          "License :: OSI Approved :: MIT License",
          "Operating System :: Microsoft :: Windows",
          "Operating System :: MacOS",
          "Operating System :: POSIX :: Linux",
          "Programming Language :: Python",
          "Programming Language :: Python :: 3",
          "Programming Language :: Python :: 3 :: Only",
          "Programming Language :: Python :: 3.6",
          "Programming Language :: Python :: 3.7",
          "Programming Language :: Python :: 3.8",
          "Programming Language :: Python :: 3.9",
          "Programming Language :: Python :: 3.10",
          "Programming Language :: Python :: 3.11",
          "Programming Language :: Python :: 3.12",
          "Programming Language :: C++",
          "Programming Language :: Python :: Implementation :: CPython",
          "Topic :: Scientific/Engineering",
          "Topic :: Software Development",
      ],
      cmdclass={
          'install': CustomInstall,
          'build_ext': CustomBuildExt,
          'develop': CustomBuildExtDev},
      )

PyCamera 結構體表示包裹 C Camera 物件的 Python 物件。此處理程序是一個指向 Camera 類別實例的指標。

方法

• PyCamera_dealloc
  

  #include <Python.h>
  #include <structmember.h>
  #include "Camera.h"
  

  解除分配 Camera 物件並釋放關聯的記憶體。

• PyCamera_new
  

  typedef struct
  {
      PyObject_HEAD Camera *handler;
  } PyCamera;
  

  建立 PyCamera 的新實例。它為Python對象分配內存，創建一個新的Camera對象，並將其分配給self->handler。

• 開放
  

  static int PyCamera_clear(PyCamera *self)
  {
      if (self->handler)
      {
          delete self->handler;
      }
      return 0;
  }
  
  static void PyCamera_dealloc(PyCamera *self)
  {
      PyCamera_clear(self);
      Py_TYPE(self)->tp_free((PyObject *)self);
  }
  
  

  開啟指定索引的相機。

• 列表媒體類型
  

  static PyObject *PyCamera_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
  {
      PyCamera *self;
  
      self = (PyCamera *)type->tp_alloc(type, 0);
      if (self != NULL)
      {
          self->handler = new Camera();
      }
  
      return (PyObject *)self;
  }
  
  

  傳回支援的媒體類型清單。對於 Windows，它將寬字串轉換為 Python Unicode 物件。

• 發布
  

  static PyObject *open(PyObject *obj, PyObject *args)
  {
      PyCamera *self = (PyCamera *)obj;
  
      int index = 0;
      if (!PyArg_ParseTuple(args, "i", &index))
      {
          return NULL;
      }
  
      bool ret = self->handler->Open(index);
      return Py_BuildValue("i", ret);
  }
  

  釋放相機。

• 設定解析度
  

  static PyObject *listMediaTypes(PyObject *obj, PyObject *args)
  {
      PyCamera *self = (PyCamera *)obj;
  
      std::vector<MediaTypeInfo> mediaTypes = self->handler->ListSupportedMediaTypes();
  
      PyObject *pyList = PyList_New(0);
  
      for (size_t i = 0; i < mediaTypes.size(); i++)
      {
          MediaTypeInfo &mediaType = mediaTypes[i];
  
  #ifdef _WIN32
          PyObject *subtypeName = PyUnicode_FromWideChar(mediaType.subtypeName, wcslen(mediaType.subtypeName));
          PyObject *pyMediaType = Py_BuildValue("{s:i,s:i,s:O}",
                                                "width", mediaType.width,
                                                "height", mediaType.height,
                                                "subtypeName", subtypeName);
          if (subtypeName != NULL)
          {
              Py_DECREF(subtypeName);
          }
  
  #else
          PyObject *pyMediaType = Py_BuildValue("{s:i,s:i,s:s}",
                                                "width", mediaType.width,
                                                "height", mediaType.height,
                                                "subtypeName", mediaType.subtypeName);
  #endif
  
          PyList_Append(pyList, pyMediaType);
      }
  
      return pyList;
  }
  
  

  設定相機的解析度。

• 捕獲幀
  

  static PyObject *release(PyObject *obj, PyObject *args)
  {
      PyCamera *self = (PyCamera *)obj;
  
      self->handler->Release();
      Py_RETURN_NONE;
  }
  

  從相機捕獲幀並將 RGB 資料作為 Python 位元組數組傳回。

• getWidth 和 getHeight
  

  static PyObject *setResolution(PyObject *obj, PyObject *args)
  {
      PyCamera *self = (PyCamera *)obj;
      int width = 0, height = 0;
      if (!PyArg_ParseTuple(args, "ii", &width, &height))
      {
          return NULL;
      }
      int ret = self->handler->SetResolution(width, height);
      return Py_BuildValue("i", ret);
  }
  

  傳回捕獲幀的寬度和高度。

實例方法

static PyObject *captureFrame(PyObject *obj, PyObject *args)
{
    PyCamera *self = (PyCamera *)obj;

    FrameData frame = self->handler->CaptureFrame();
    if (frame.rgbData)
    {
        PyObject *rgbData = PyByteArray_FromStringAndSize((const char *)frame.rgbData, frame.size);
        PyObject *pyFrame = Py_BuildValue("iiiO", frame.width, frame.height, frame.size, rgbData);
        ReleaseFrame(frame);

        return pyFrame;
    }
    else
    {
        Py_RETURN_NONE;
    }
}

定義 PyCamera Python 物件上可用的方法。這些方法與上面定義的對應 C 函數相關聯。

PyCamera型

static PyObject *getWidth(PyObject *obj, PyObject *args)
{
    PyCamera *self = (PyCamera *)obj;

    int width = self->handler->frameWidth;
    return Py_BuildValue("i", width);
}

static PyObject *getHeight(PyObject *obj, PyObject *args)
{
    PyCamera *self = (PyCamera *)obj;

    int height = self->handler->frameHeight;
    return Py_BuildValue("i", height);
}

定義 PyCamera 類型，包括其方法、記憶體分配、釋放和其他行為。

pywindow.h

包括

static PyMethodDef instance_methods[] = {
    {"open", open, METH_VARARGS, NULL},
    {"listMediaTypes", listMediaTypes, METH_VARARGS, NULL},
    {"release", release, METH_VARARGS, NULL},
    {"setResolution", setResolution, METH_VARARGS, NULL},
    {"captureFrame", captureFrame, METH_VARARGS, NULL},
    {"getWidth", getWidth, METH_VARARGS, NULL},
    {"getHeight", getHeight, METH_VARARGS, NULL},
    {NULL, NULL, 0, NULL}};

• Python.h：使用 Python C API 所需的。
• structmember.h：提供管理物件成員的巨集。
• CameraPreview.h：定義CameraWindow類，用於顯示相機預覽並與其互動。

PyWindow 結構體定義

static PyTypeObject PyCameraType = {
    PyVarObject_HEAD_INIT(NULL, 0) "litecam.PyCamera", /* tp_name */
    sizeof(PyCamera),                                  /* tp_basicsize */
    0,                                                 /* tp_itemsize */
    (destructor)PyCamera_dealloc,                      /* tp_dealloc */
    0,                                                 /* tp_print */
    0,                                                 /* tp_getattr */
    0,                                                 /* tp_setattr */
    0,                                                 /* tp_reserved */
    0,                                                 /* tp_repr */
    0,                                                 /* tp_as_number */
    0,                                                 /* tp_as_sequence */
    0,                                                 /* tp_as_mapping */
    0,                                                 /* tp_hash  */
    0,                                                 /* tp_call */
    0,                                                 /* tp_str */
    PyObject_GenericGetAttr,                           /* tp_getattro */
    PyObject_GenericSetAttr,                           /* tp_setattro */
    0,                                                 /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,          /*tp_flags*/
    "PyCamera",                                        /* tp_doc */
    0,                                                 /* tp_traverse */
    0,                                                 /* tp_clear */
    0,                                                 /* tp_richcompare */
    0,                                                 /* tp_weaklistoffset */
    0,                                                 /* tp_iter */
    0,                                                 /* tp_iternext */
    instance_methods,                                  /* tp_methods */
    0,                                                 /* tp_members */
    0,                                                 /* tp_getset */
    0,                                                 /* tp_base */
    0,                                                 /* tp_dict */
    0,                                                 /* tp_descr_get */
    0,                                                 /* tp_descr_set */
    0,                                                 /* tp_dictoffset */
    0,                                                 /* tp_init */
    0,                                                 /* tp_alloc */
    PyCamera_new,                                      /* tp_new */
};

定義一個包裝 C CameraWindow 物件的 PyWindow 結構。 handler 成員指向 CameraWindow 的一個實例。

PyWindow 物件的方法

• PyWindow_dealloc
  

  #include <Python.h>
  #include <structmember.h>
  #include "CameraPreview.h"
  

  取消分配CameraWindow物件並釋放記憶體。

• PyWindow_new
  

  typedef struct
  {
      PyObject_HEAD CameraWindow *handler;
  } PyWindow;
  
  

  建立 PyWindow 的新實例。它為Python物件分配內存，建立一個新的CameraWindow對象，並將其分配給self->handler。

• 等待鍵
  

  python-lite-camera
  │
  │── include
  │   ├── Camera.h
  │   ├── CameraPreview.h
  │   ├── stb_image_write.h
  │── lib
  │   ├── linux
  │   │   ├── liblitecam.so
  │   ├── macos
  │   │   ├── liblitecam.dylib
  │   ├── windows
  │   │   ├── litecam.dll
  │   │   ├── litecam.lib
  ├── src
  │   ├── litecam.cpp
  │   ├── pycamera.h
  │   ├── pywindow.h
  │── litecam
  │   ├── __init__.py
  │── setup.py
  │── MANIFEST.in
  │── README.md
  

  等待按鍵事件，如果按鍵與指定字元匹配則傳回 False。 False 意味著應用程式應該退出。

• showFrame
  

  from setuptools.command import build_ext
  from setuptools import setup, Extension
  import sys
  import os
  import io
  from setuptools.command.install import install
  import shutil
  from pathlib import Path
  
  lib_dir = ''
  
  sources = [
      "src/litecam.cpp",
  ]
  
  include_dirs = [os.path.join(os.path.dirname(__file__), "include")]
  
  libraries = ['litecam']
  
  extra_compile_args = []
  
  if sys.platform == "linux" or sys.platform == "linux2":
      lib_dir = 'lib/linux'
      extra_compile_args = ['-std=c++11']
      extra_link_args = ["-Wl,-rpath=$ORIGIN"]
  elif sys.platform == "darwin":
      lib_dir = 'lib/macos'
      extra_compile_args = ['-std=c++11']
      extra_link_args = ["-Wl,-rpath,@loader_path"]
  elif sys.platform == "win32":
      lib_dir = 'lib/windows'
      extra_link_args = []
  
  else:
      raise RuntimeError("Unsupported platform")
  
  
  long_description = io.open("README.md", encoding="utf-8").read()
  
  module_litecam = Extension(
      "litecam",
      sources=sources,
      include_dirs=include_dirs,
      library_dirs=[lib_dir],
      libraries=libraries,
      extra_compile_args=extra_compile_args,
      extra_link_args=extra_link_args,
  )
  
  def copyfiles(src, dst):
      if os.path.isdir(src):
          filelist = os.listdir(src)
          for file in filelist:
              libpath = os.path.join(src, file)
              shutil.copy2(libpath, dst)
      else:
          shutil.copy2(src, dst)
  
  
  class CustomBuildExt(build_ext.build_ext):
      def run(self):
          build_ext.build_ext.run(self)
          dst = os.path.join(self.build_lib, "litecam")
          copyfiles(lib_dir, dst)
          filelist = os.listdir(self.build_lib)
          for file in filelist:
              filePath = os.path.join(self.build_lib, file)
              if not os.path.isdir(file):
                  copyfiles(filePath, dst)
                  os.remove(filePath)
  
  
  class CustomBuildExtDev(build_ext.build_ext):
      def run(self):
          build_ext.build_ext.run(self)
          dev_folder = os.path.join(Path(__file__).parent, 'litecam')
          copyfiles(lib_dir, dev_folder)
          filelist = os.listdir(self.build_lib)
          for file in filelist:
              filePath = os.path.join(self.build_lib, file)
              if not os.path.isdir(file):
                  copyfiles(filePath, dev_folder)
  
  
  class CustomInstall(install):
      def run(self):
          install.run(self)
  
  
  setup(name='lite-camera',
        version='2.0.1',
        description='LiteCam is a lightweight, cross-platform library for capturing RGB frames from cameras and displaying them. Designed with simplicity and ease of integration in mind, LiteCam supports Windows, Linux and macOS platforms.',
        long_description=long_description,
        long_description_content_type="text/markdown",
        author='yushulx',
        url='https://github.com/yushulx/python-lite-camera',
        license='MIT',
        packages=['litecam'],
        ext_modules=[module_litecam],
        classifiers=[
             "Development Status :: 5 - Production/Stable",
             "Environment :: Console",
             "Intended Audience :: Developers",
            "Intended Audience :: Education",
            "Intended Audience :: Information Technology",
            "Intended Audience :: Science/Research",
            "License :: OSI Approved :: MIT License",
            "Operating System :: Microsoft :: Windows",
            "Operating System :: MacOS",
            "Operating System :: POSIX :: Linux",
            "Programming Language :: Python",
            "Programming Language :: Python :: 3",
            "Programming Language :: Python :: 3 :: Only",
            "Programming Language :: Python :: 3.6",
            "Programming Language :: Python :: 3.7",
            "Programming Language :: Python :: 3.8",
            "Programming Language :: Python :: 3.9",
            "Programming Language :: Python :: 3.10",
            "Programming Language :: Python :: 3.11",
            "Programming Language :: Python :: 3.12",
            "Programming Language :: C++",
            "Programming Language :: Python :: Implementation :: CPython",
            "Topic :: Scientific/Engineering",
            "Topic :: Software Development",
        ],
        cmdclass={
            'install': CustomInstall,
            'build_ext': CustomBuildExt,
            'develop': CustomBuildExtDev},
        )
  

  在視窗中顯示一個框架。

• 繪製輪廓
  

  #include <Python.h>
  #include <structmember.h>
  #include "Camera.h"
  

  在框架上繪製輪廓（一系列點）。

• 繪製文字
  

  typedef struct
  {
      PyObject_HEAD Camera *handler;
  } PyCamera;
  

  在框架上繪製文字。

視窗實例方法

static int PyCamera_clear(PyCamera *self)
{
    if (self->handler)
    {
        delete self->handler;
    }
    return 0;
}

static void PyCamera_dealloc(PyCamera *self)
{
    PyCamera_clear(self);
    Py_TYPE(self)->tp_free((PyObject *)self);
}

定義 PyWindow Python 物件上可用的方法。

PyWindow類型

static PyObject *PyCamera_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
    PyCamera *self;

    self = (PyCamera *)type->tp_alloc(type, 0);
    if (self != NULL)
    {
        self->handler = new Camera();
    }

    return (PyObject *)self;
}

定義 PyWindow 類型，包括其方法、記憶體分配、釋放和其他行為。

litecam.cpp

static PyObject *open(PyObject *obj, PyObject *args)
{
    PyCamera *self = (PyCamera *)obj;

    int index = 0;
    if (!PyArg_ParseTuple(args, "i", &index))
    {
        return NULL;
    }

    bool ret = self->handler->Open(index);
    return Py_BuildValue("i", ret);
}

說明：

• getDeviceList：傳回可用攝影機的清單。
• saveJpeg：將畫面儲存為 JPEG 影像。
• PyInit_litecam：初始化litecam模組並註冊PyCamera和PyWindow類型。

建構 Python 相機 SDK

• 開發模式
  

  static PyObject *listMediaTypes(PyObject *obj, PyObject *args)
  {
      PyCamera *self = (PyCamera *)obj;
  
      std::vector<MediaTypeInfo> mediaTypes = self->handler->ListSupportedMediaTypes();
  
      PyObject *pyList = PyList_New(0);
  
      for (size_t i = 0; i < mediaTypes.size(); i++)
      {
          MediaTypeInfo &mediaType = mediaTypes[i];
  
  #ifdef _WIN32
          PyObject *subtypeName = PyUnicode_FromWideChar(mediaType.subtypeName, wcslen(mediaType.subtypeName));
          PyObject *pyMediaType = Py_BuildValue("{s:i,s:i,s:O}",
                                                "width", mediaType.width,
                                                "height", mediaType.height,
                                                "subtypeName", subtypeName);
          if (subtypeName != NULL)
          {
              Py_DECREF(subtypeName);
          }
  
  #else
          PyObject *pyMediaType = Py_BuildValue("{s:i,s:i,s:s}",
                                                "width", mediaType.width,
                                                "height", mediaType.height,
                                                "subtypeName", mediaType.subtypeName);
  #endif
  
          PyList_Append(pyList, pyMediaType);
      }
  
      return pyList;
  }
  
  

• 輪組
  

  static PyObject *release(PyObject *obj, PyObject *args)
  {
      PyCamera *self = (PyCamera *)obj;
  
      self->handler->Release();
      Py_RETURN_NONE;
  }
  

• 來源分佈
  

  static PyObject *setResolution(PyObject *obj, PyObject *args)
  {
      PyCamera *self = (PyCamera *)obj;
      int width = 0, height = 0;
      if (!PyArg_ParseTuple(args, "ii", &width, &height))
      {
          return NULL;
      }
      int ret = self->handler->SetResolution(width, height);
      return Py_BuildValue("i", ret);
  }
  

實作 Python 多條碼掃描器的步驟

1. 安裝Python相機SDK和Dynamsoft Barcode Reader SDK：
   

   static PyObject *captureFrame(PyObject *obj, PyObject *args)
   {
       PyCamera *self = (PyCamera *)obj;
   
       FrameData frame = self->handler->CaptureFrame();
       if (frame.rgbData)
       {
           PyObject *rgbData = PyByteArray_FromStringAndSize((const char *)frame.rgbData, frame.size);
           PyObject *pyFrame = Py_BuildValue("iiiO", frame.width, frame.height, frame.size, rgbData);
           ReleaseFrame(frame);
   
           return pyFrame;
       }
       else
       {
           Py_RETURN_NONE;
       }
   }
   

2. 取得 Dynamsoft Barcode Reader 30 天免費試用許可證。

3. 建立用於多條碼掃描的 Python 腳本：
   

   static PyObject *getWidth(PyObject *obj, PyObject *args)
   {
       PyCamera *self = (PyCamera *)obj;
   
       int width = self->handler->frameWidth;
       return Py_BuildValue("i", width);
   }
   
   static PyObject *getHeight(PyObject *obj, PyObject *args)
   {
       PyCamera *self = (PyCamera *)obj;
   
       int height = self->handler->frameHeight;
       return Py_BuildValue("i", height);
   }
   

   將 LICENSE-KEY 替換為您的 Dynamsoft Barcode Reader 許可證金鑰。

4. 運行腳本：
   

   static PyMethodDef instance_methods[] = {
       {"open", open, METH_VARARGS, NULL},
       {"listMediaTypes", listMediaTypes, METH_VARARGS, NULL},
       {"release", release, METH_VARARGS, NULL},
       {"setResolution", setResolution, METH_VARARGS, NULL},
       {"captureFrame", captureFrame, METH_VARARGS, NULL},
       {"getWidth", getWidth, METH_VARARGS, NULL},
       {"getHeight", getHeight, METH_VARARGS, NULL},
       {NULL, NULL, 0, NULL}};
   
   

   

原始碼

https://github.com/yushulx/python-lite-camera

以上是建立 Python 相機 SDK 並使用它進行多條碼掃描的詳細內容。更多資訊請關注PHP中文網其他相關文章！