Python使用PIL构建图片裁剪工具的实现步骤_Python

c:\pythoncode\new\cropimageandsave.py

功能特性

图片加载：支持加载 jpg 和 png 格式的图片。
动态裁剪：通过鼠标绘制矩形选择框进行裁剪。
缩放适配：图片会根据面板大小自动缩放显示。
保存裁剪结果：裁剪后的图片可以保存为 png 文件。

代码实现

完整代码如下：

import wx
import os
from pil import image
 
class imagecropperframe(wx.frame):
    def __init__(self):
        super().__init__(parent=none, title='图片裁剪工具', size=(800, 600))
        self.init_ui()
        
    def init_ui(self):
        # 创建菜单栏
        menubar = wx.menubar()
        file_menu = wx.menu()
        open_item = file_menu.append(wx.id_open, '打开图片', '打开一个图片文件')
        menubar.append(file_menu, '文件')
        self.setmenubar(menubar)
        
        # 创建面板和图片显示控件
        self.panel = wx.panel(self)
        self.image_panel = wx.panel(self.panel)
        self.image_panel.setbackgroundcolour(wx.colour(200, 200, 200))
        
        # 初始化变量
        self.image = none
        self.bitmap = none
        self.start_pos = none
        self.current_pos = none
        self.is_drawing = false
        
        # 设置布局
        sizer = wx.boxsizer(wx.vertical)
        sizer.add(self.image_panel, 1, wx.expand)
        self.panel.setsizer(sizer)
        
        # 绑定事件
        self.bind(wx.evt_menu, self.on_open, open_item)
        self.image_panel.bind(wx.evt_paint, self.on_paint)
        self.image_panel.bind(wx.evt_left_down, self.on_left_down)
        self.image_panel.bind(wx.evt_left_up, self.on_left_up)
        self.image_panel.bind(wx.evt_motion, self.on_motion)
        
    def on_open(self, event):
        # 打开文件对话框
        with wx.filedialog(self, "选择图片文件", 
                          wildcard="图片文件 (*.jpg;*.jpeg;*.png)|*.jpg;*.jpeg;*.png",
                          style=wx.fd_open | wx.fd_file_must_exist) as filedialog:
            
            if filedialog.showmodal() == wx.id_cancel:
                return
            
            # 加载图片
            pathname = filedialog.getpath()
            self.load_image(pathname)
            self.image_path = pathname
    
    def load_image(self, path):
        # 使用pil加载图片
        self.pil_image = image.open(path)
        # 转换为wx.bitmap
        self.image = wx.image(path, wx.bitmap_type_any)
        # 调整图片大小以适应窗口
        self.scale_image()
        self.refresh()
    
    def scale_image(self):
        # 获取面板大小
        panel_size = self.image_panel.getsize()
        # 计算缩放比例
        width_ratio = panel_size.width / self.image.getwidth()
        height_ratio = panel_size.height / self.image.getheight()
        scale = min(width_ratio, height_ratio)
        
        # 缩放图片
        new_width = int(self.image.getwidth() * scale)
        new_height = int(self.image.getheight() * scale)
        self.image = self.image.scale(new_width, new_height)
        self.bitmap = wx.bitmap(self.image)
        
        # 保存缩放比例用于裁剪
        self.scale_factor = scale
    
    def on_paint(self, event):
        dc = wx.paintdc(self.image_panel)
        if self.bitmap:
            dc.drawbitmap(self.bitmap, 0, 0)
        
        # 绘制选择框
        if self.start_pos and self.current_pos:
            dc.setpen(wx.pen(wx.red, 1, wx.penstyle_dot))
            dc.setbrush(wx.transparent_brush)
            x = min(self.start_pos[0], self.current_pos[0])
            y = min(self.start_pos[1], self.current_pos[1])
            w = abs(self.current_pos[0] - self.start_pos[0])
            h = abs(self.current_pos[1] - self.start_pos[1])
            dc.drawrectangle(x, y, w, h)
    
    def on_left_down(self, event):
        self.start_pos = event.getposition()
        self.current_pos = self.start_pos
        self.is_drawing = true
    
    def on_motion(self, event):
        if self.is_drawing:
            self.current_pos = event.getposition()
            self.refresh()
    
    def on_left_up(self, event):
        if self.is_drawing:
            self.is_drawing = false
            # 获取选择区域
            x1 = min(self.start_pos[0], self.current_pos[0])
            y1 = min(self.start_pos[1], self.current_pos[1])
            x2 = max(self.start_pos[0], self.current_pos[0])
            y2 = max(self.start_pos[1], self.current_pos[1])
            
            # 转换回原始图片坐标
            orig_x1 = int(x1 / self.scale_factor)
            orig_y1 = int(y1 / self.scale_factor)
            orig_x2 = int(x2 / self.scale_factor)
            orig_y2 = int(y2 / self.scale_factor)
            
            # 裁剪图片
            cropped = self.pil_image.crop((orig_x1, orig_y1, orig_x2, orig_y2))
            
            # 生成保存路径
            directory = os.path.dirname(self.image_path)
            filename = os.path.splitext(os.path.basename(self.image_path))[0]
            save_path = os.path.join(directory, f"{filename}_cropped.png")
            
            # 保存裁剪后的图片
            cropped.save(save_path)
            
            # 显示成功消息
            wx.messagebox(f"裁剪后的图片已保存至:\n{save_path}", 
                         "保存成功", 
                         wx.ok | wx.icon_information)
            
            # 重置选择区域
            self.start_pos = none
            self.current_pos = none
            self.refresh()
 
if __name__ == '__main__':
    app = wx.app()
    frame = imagecropperframe()
    frame.show()
    app.mainloop()