基于python开发图片比例调整工具的示例代码

class ImageRatioApp(wx.Frame):
    def __init__(self):
        super().__init__(None, title="图片比例调整工具", size=(900, 700))
        
        # 支持的图片格式
        self.supported_formats = "图片文件 (*.jpg;*.jpeg;*.png;*.bmp;*.gif;*.tiff)|*.jpg;*.jpeg;*.png;*.bmp;*.gif;*.tiff"
        
        # 比例选项
        self.ratio_options = {
            "21:9 (宽屏电影)": (21, 9),
            "16:9 (标准高清宽屏)": (16, 9),
            "4:3 (传统电视/显示器)": (4, 3),
            "1:1 (正方形)": (1, 1),
            "3:4 (竖向)": (3, 4),
            "9:16 (竖向手机短视频)": (9, 16)

def init_ui(self):
    # 创建主面板
    panel = wx.Panel(self)
    main_sizer = wx.BoxSizer(wx.VERTICAL)
    
    # 顶部控制区域
    control_panel = wx.Panel(panel)
    control_sizer = wx.BoxSizer(wx.HORIZONTAL)
    
    # 图片显示区域 - 水平分割
    image_panel = wx.Panel(panel)
    image_sizer = wx.BoxSizer(wx.HORIZONTAL)

def process_image(self):
    selected_ratio = list(self.ratio_options.keys())[self.ratio_choice.GetSelection()]
    ratio_w, ratio_h = self.ratio_options[selected_ratio]
    
    orig_w, orig_h = self.original_image.size
    
    # 关键算法：计算目标尺寸
    if orig_w / orig_h > ratio_w / ratio_h:
        # 原图更宽，以高度为准
        target_h = orig_h
        target_w = int(target_h * ratio_w / ratio_h)
    else:
        # 原图更高，以宽度为准
        target_w = orig_w
        target_h = int(target_w * ratio_h / ratio_w)

# 创建新的空白图像
new_image = Image.new('RGB', (target_w, target_h), (255, 255, 255))
 
# 计算粘贴位置（居中）
paste_x = (target_w - orig_w) // 2
paste_y = (target_h - orig_h) // 2
 
# 智能处理：裁剪 vs 扩展
if orig_w > target_w or orig_h > target_h:
    # 需要裁剪的情况
    crop_x = max(0, (orig_w - target_w) // 2)
    crop_y = max(0, (orig_h - target_h) // 2)
    crop_box = (
        crop_x,
        crop_y,
        crop_x + min(target_w, orig_w),
        crop_y + min(target_h, orig_h)
    )
    cropped = self.original_image.crop(crop_box)
    new_image.paste(cropped, (max(0, paste_x), max(0, paste_y)))
else:
    # 直接粘贴到中心（扩展情况）
    new_image.paste(self.original_image, (paste_x, paste_y))

def display_image(self, pil_image, display_control):
    display_size = display_control.GetSize()
    max_width, max_height = display_size.width - 10, display_size.height - 10
    
    # 计算缩放比例，保持宽高比
    img_width, img_height = pil_image.size
    scale_w = max_width / img_width
    scale_h = max_height / img_height
    scale = min(scale_w, scale_h, 1.0)  # 关键：不放大，只缩小
    
    # 使用高质量缩放算法
    resized_image = pil_image.resize((new_width, new_height), Image.Resampling.LANCZOS)

def pil_to_wx_image(self, pil_image):
    # 确保是RGB格式
    if pil_image.mode != 'RGB':
        pil_image = pil_image.convert('RGB')
    
    # 获取图像数据
    width, height = pil_image.size
    data = pil_image.tobytes()
    
    # 创建wx.Image
    wx_image = wx.Image(width, height, data)
    return wx_image

def on_save_image(self, event):
    # 根据文件扩展名确定格式
    format_map = {
        '.jpg': 'JPEG',
        '.jpeg': 'JPEG',
        '.png': 'PNG',
        '.bmp': 'BMP',
        '.tiff': 'TIFF'
    }
    
    # JPEG特殊处理
    if save_format == 'JPEG' and self.processed_image.mode == 'RGBA':
        rgb_image = Image.new('RGB', self.processed_image.size, (255, 255, 255))
        rgb_image.paste(self.processed_image, mask=self.processed_image.split()[-1])
        rgb_image.save(file_path, format=save_format, quality=95)

def on_ratio_change(self, event):
    if self.original_image:  # 只有在图片已加载时才处理
        self.process_image()

self.original_image = None
self.processed_image = None

self.save_btn.Enable(False)  # 初始禁用
# 处理完成后启用
self.save_btn.Enable(True)

try:
    self.original_image = Image.open(file_path)
    # ... 处理逻辑
except Exception as e:
    wx.MessageBox(f"加载图片失败: {str(e)}", "错误", wx.OK | wx.ICON_ERROR)
    self.status_bar.SetStatusText("加载图片失败")

self.status_bar.SetStatusText(f"已加载图片: {os.path.basename(file_path)}")
self.status_bar.SetStatusText(f"已调整为 {selected_ratio} 比例")

self.ratio_options = {
    "21:9 (宽屏电影)": (21, 9),
    # 可以轻松添加新比例
}

format_map = {
    # 可以轻松添加新格式支持
}