Python插件化开发实战:开发个图片浏览器

news2025/1/8 10:42:48

在本篇教程中，我将详细介绍如何使用Python开发一个基于插件架构的图片浏览器。这个项目将展示如何实现插件系统、如何处理图片显示,以及如何使用wxPython构建GUI界面。
“C:\pythoncode\pythonplugin\your_project\main_app.py”
在这里插入图片描述

项目概述

我们将开发一个具有以下功能的应用:

支持动态加载插件
可以浏览选择图片文件夹
以缩略图方式显示JPEG图片
使用wxPython构建友好的用户界面

项目结构

项目采用如下目录结构:

your_project/
    ├── main_app.py          # 主程序
    ├── plugin_interface.py  # 插件接口定义
    ├── plugin_manager.py    # 插件管理器
    └── plugins/             # 插件目录
        ├── __init__.py
        └── example_plugin.py # 示例插件

代码实现

1. 插件接口 (plugin_interface.py)

首先定义插件接口,所有插件都需要继承这个基类:

# plugin_interface.py
class PluginInterface:
    def __init__(self):
        self.name = "Base Plugin"
        self.description = "Base plugin description"
        self.parameters = {}

    def initialize(self):
        pass

    def execute(self, parameters=None):
        pass

    def cleanup(self):
        pass

2. 插件管理器 (plugin_manager.py)

插件管理器负责加载和管理插件:

# plugin_manager.py
import os
import importlib.util

class PluginManager:
    def __init__(self):
        self.plugins = {}
    
    def load_plugin(self, plugin_path):
        # 获取插件文件名（不含扩展名）
        plugin_name = os.path.splitext(os.path.basename(plugin_path))[0]
        
        # 动态导入插件模块
        spec = importlib.util.spec_from_file_location(plugin_name, plugin_path)
        module = importlib.util.module_from_spec(spec)
        spec.loader.exec_module(module)
        
        # 寻找继承自PluginInterface的类
        for attr_name in dir(module):
            attr = getattr(module, attr_name)
            if isinstance(attr, type) and attr.__module__ == plugin_name and hasattr(attr, 'execute'):
                plugin_instance = attr()
                self.plugins[plugin_name] = plugin_instance
                break
        
    def load_plugins_from_directory(self, directory):
        if not os.path.exists(directory):
            os.makedirs(directory)
            
        for filename in os.listdir(directory):
            if filename.endswith('.py') and not filename.startswith('__'):
                plugin_path = os.path.join(directory, filename)
                self.load_plugin(plugin_path)
                
    def get_plugin(self, plugin_name):
        return self.plugins.get(plugin_name)

3. 图片浏览插件 (example_plugin.py)

实现图片浏览功能的插件:

# example_plugin.py
from plugin_interface import PluginInterface
import wx
import os
from PIL import Image
import io

class ThumbnailFrame(wx.Frame):
    def __init__(self, parent, title, image_folder):
        super().__init__(parent, title=title, size=(800, 600))
        
        self.panel = wx.ScrolledWindow(self)
        self.panel.SetScrollbars(1, 1, 1, 1)
        
        # 创建网格布局
        self.grid_sizer = wx.GridSizer(rows=0, cols=4, hgap=10, vgap=10)
        self.panel.SetSizer(self.grid_sizer)
        
        # 加载图片
        self.load_images(image_folder)
        
    def load_images(self, folder_path):
        for filename in os.listdir(folder_path):
            if filename.lower().endswith(('.jpg', '.jpeg')):
                image_path = os.path.join(folder_path, filename)
                try:
                    # 使用PIL打开图片并调整大小
                    with Image.open(image_path) as img:
                        # 调整图片大小为缩略图
                        img.thumbnail((150, 150))
                        # 转换为wx.Bitmap
                        width, height = img.size
                        img_data = io.BytesIO()
                        img.save(img_data, format='PNG')
                        img_data = img_data.getvalue()
                        wx_image = wx.Image(io.BytesIO(img_data))
                        bitmap = wx_image.ConvertToBitmap()
                        
                        # 创建图片控件
                        img_button = wx.BitmapButton(self.panel, bitmap=bitmap)
                        img_button.SetToolTip(filename)
                        
                        # 添加到网格
                        self.grid_sizer.Add(img_button, 0, wx.ALL, 5)
                except Exception as e:
                    print(f"Error loading image {filename}: {str(e)}")
        
        self.panel.Layout()

class ExamplePlugin(PluginInterface):
    def __init__(self):
        super().__init__()
        self.name = "Image Thumbnail Plugin"
        self.description = "Display thumbnails of JPEG images in a folder"
        
    def execute(self, parameters=None):
        if not parameters or 'image_folder' not in parameters:
            print("No image folder specified")
            return
            
        image_folder = parameters['image_folder']
        if not os.path.exists(image_folder):
            print(f"Folder does not exist: {image_folder}")
            return
            
        # 创建并显示缩略图窗口
        frame = ThumbnailFrame(None, "Image Thumbnails", image_folder)
        frame.Show()

4. 主程序 (main_app.py)

主程序创建GUI界面并协调插件的使用:

# main_app.py
import wx
from plugin_manager import PluginManager
import os

class MainFrame(wx.Frame):
    def __init__(self):
        super().__init__(parent=None, title='Plugin Demo', size=(400, 300))
        self.plugin_manager = PluginManager()
        
        # 加载插件
        self.plugin_manager.load_plugins_from_directory("plugins")
        
        # 创建界面
        self.init_ui()
        
    def init_ui(self):
        panel = wx.Panel(self)
        vbox = wx.BoxSizer(wx.VERTICAL)
        
        # 创建插件列表
        plugin_list = wx.ListBox(panel)
        for plugin_name in self.plugin_manager.plugins:
            plugin_list.Append(plugin_name)
            
        # 添加文件夹选择按钮
        select_folder_button = wx.Button(panel, label='Select Image Folder')
        select_folder_button.Bind(wx.EVT_BUTTON, self.on_select_folder)
        
        # 添加执行按钮
        execute_button = wx.Button(panel, label='Execute Plugin')
        execute_button.Bind(wx.EVT_BUTTON, self.on_execute)
        
        vbox.Add(plugin_list, 1, wx.EXPAND | wx.ALL, 5)
        vbox.Add(select_folder_button, 0, wx.EXPAND | wx.ALL, 5)
        vbox.Add(execute_button, 0, wx.EXPAND | wx.ALL, 5)
        
        panel.SetSizer(vbox)
        self.plugin_list = plugin_list
        self.selected_folder = None
        
    def on_select_folder(self, event):
        dlg = wx.DirDialog(self, "Choose a directory:",
                          style=wx.DD_DEFAULT_STYLE)
        
        if dlg.ShowModal() == wx.ID_OK:
            self.selected_folder = dlg.GetPath()
            
        dlg.Destroy()
        
    def on_execute(self, event):
        selection = self.plugin_list.GetSelection()
        if selection != wx.NOT_FOUND:
            plugin_name = self.plugin_list.GetString(selection)
            plugin = self.plugin_manager.get_plugin(plugin_name)
            
            if plugin:
                if not self.selected_folder:
                    wx.MessageBox('Please select an image folder first!',
                                'No Folder Selected',
                                wx.OK | wx.ICON_INFORMATION)
                    return
                    
                # 执行插件，传入文件夹路径
                plugin.execute({'image_folder': self.selected_folder})

if __name__ == '__main__':
    app = wx.App()
    frame = MainFrame()
    frame.Show()
    app.MainLoop()