455 lines
13 KiB
Python
455 lines
13 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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"""
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Fabric.js JSON 生成器
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负责生成 Fabric.js 兼容的 JSON 格式
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"""
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import logging
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import base64
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from io import BytesIO
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from typing import Dict, Any, Optional, List, Tuple
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logger = logging.getLogger(__name__)
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try:
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from PIL import Image
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PIL_AVAILABLE = True
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except ImportError:
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PIL_AVAILABLE = False
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class FabricGenerator:
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"""
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Fabric.js JSON 生成器
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职责：
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- 生成 Fabric.js 兼容的 JSON
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- 创建各种图形对象（图片、文本、形状）
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- 处理布局计算
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"""
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# Fabric.js 版本
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FABRIC_VERSION = "5.3.0"
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# 基础画布尺寸
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BASE_WIDTH = 1350
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BASE_HEIGHT = 1800
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def __init__(self):
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self.logger = logging.getLogger(f"{__name__}.FabricGenerator")
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def generate(
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self,
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content: Dict[str, Any],
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template_id: str,
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image_size: Tuple[int, int],
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background_image: Optional['Image.Image'] = None,
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template_handler=None
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) -> Dict[str, Any]:
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"""
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生成 Fabric.js JSON
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Args:
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content: 海报内容
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template_id: 模板 ID
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image_size: 画布尺寸 (width, height)
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background_image: 背景图片
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template_handler: 模板处理器实例
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Returns:
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Fabric.js JSON 字典
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"""
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try:
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self.logger.info(f"开始生成 Fabric.js JSON，模板: {template_id}")
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# 如果有模板处理器且支持统一渲染
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if template_handler and hasattr(template_handler, '_unified_render'):
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return self._generate_with_template(
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content, template_handler, background_image
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)
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# 否则使用通用逻辑
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return self._generate_generic(
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content, template_id, image_size, background_image
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)
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except Exception as e:
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self.logger.error(f"Fabric.js JSON 生成失败: {e}")
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return self._create_empty_json(image_size)
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def _generate_with_template(
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self,
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content: Dict[str, Any],
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template_handler,
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background_image: Optional['Image.Image']
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) -> Dict[str, Any]:
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"""使用模板处理器生成"""
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try:
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render_result = template_handler._unified_render(
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images=background_image,
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content=content,
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theme_color=None,
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glass_intensity=1.5,
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output_format='json'
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)
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if "error" in render_result:
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raise Exception(render_result["error"])
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return render_result["fabric_json"]
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except Exception as e:
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self.logger.error(f"模板渲染失败: {e}")
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raise
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def _generate_generic(
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self,
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content: Dict[str, Any],
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template_id: str,
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image_size: Tuple[int, int],
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background_image: Optional['Image.Image']
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) -> Dict[str, Any]:
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"""通用生成逻辑"""
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width, height = image_size
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objects = []
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# 1. 背景图片
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if background_image:
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objects.append(self.create_image_object(
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background_image, width, height, is_background=True
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))
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else:
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objects.append(self.create_placeholder_object(width, height))
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# 2. 渐变遮罩
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gradient_start = self._calculate_gradient_start(content, height)
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objects.append(self.create_gradient_object(width, height, gradient_start))
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# 3. 文本对象
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text_objects = self.create_text_objects(content, width, height, gradient_start)
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objects.extend(text_objects)
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return {
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"version": self.FABRIC_VERSION,
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"width": width,
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"height": height,
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"objects": objects
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}
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def _create_empty_json(self, image_size: Tuple[int, int]) -> Dict[str, Any]:
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"""创建空的 Fabric.js JSON"""
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return {
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"version": self.FABRIC_VERSION,
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"width": image_size[0],
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"height": image_size[1],
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"objects": []
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}
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def _calculate_gradient_start(self, content: Dict[str, Any], height: int) -> int:
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"""计算渐变起始位置"""
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# 估算内容高度
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estimated_height = self._estimate_content_height(content)
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# 渐变从内容区域上方开始
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return max(int(height * 0.4), height - estimated_height - 100)
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def _estimate_content_height(self, content: Dict[str, Any]) -> int:
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"""估算内容高度"""
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height = 0
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# 标题
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if content.get('title'):
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height += 80
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# 副标题
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if content.get('subtitle'):
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height += 50
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# 价格
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if content.get('price'):
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height += 60
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# 描述
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if content.get('description'):
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lines = len(content['description']) // 20 + 1
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height += lines * 30
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# 标签
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if content.get('tags'):
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height += 40
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return height + 100 # 额外边距
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# ========== 对象创建方法 ==========
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def create_image_object(
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self,
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image: 'Image.Image',
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canvas_width: int,
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canvas_height: int,
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is_background: bool = False
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) -> Dict[str, Any]:
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"""
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创建图片对象
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Args:
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image: PIL Image
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canvas_width: 画布宽度
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canvas_height: 画布高度
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is_background: 是否为背景图片
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"""
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# 转换为 base64
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image_base64 = self._image_to_base64(image)
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# 计算缩放
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scale_x = canvas_width / image.width
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scale_y = canvas_height / image.height
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scale = max(scale_x, scale_y) if is_background else min(scale_x, scale_y)
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return {
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"type": "image",
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"version": self.FABRIC_VERSION,
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"left": 0,
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"top": 0,
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"width": image.width,
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"height": image.height,
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"scaleX": scale,
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"scaleY": scale,
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"src": f"data:image/png;base64,{image_base64}",
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"selectable": not is_background,
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"evented": not is_background,
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}
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def create_placeholder_object(
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self,
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canvas_width: int,
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canvas_height: int
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) -> Dict[str, Any]:
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"""创建占位符对象"""
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return {
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"type": "rect",
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"version": self.FABRIC_VERSION,
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"left": 0,
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"top": 0,
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"width": canvas_width,
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"height": canvas_height,
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"fill": "#f0f0f0",
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"selectable": False,
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"evented": False,
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}
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def create_gradient_object(
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self,
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canvas_width: int,
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canvas_height: int,
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gradient_start: int,
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colors: Optional[Dict[str, Tuple[int, int, int]]] = None
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) -> Dict[str, Any]:
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"""
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创建渐变遮罩对象
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Args:
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canvas_width: 画布宽度
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canvas_height: 画布高度
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gradient_start: 渐变起始位置
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colors: 渐变颜色
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"""
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if colors is None:
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colors = {
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'top': (255, 255, 255),
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'bottom': (240, 240, 240)
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}
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top_color = colors.get('top', (255, 255, 255))
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bottom_color = colors.get('bottom', (240, 240, 240))
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return {
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"type": "rect",
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"version": self.FABRIC_VERSION,
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"left": 0,
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"top": gradient_start,
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"width": canvas_width,
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"height": canvas_height - gradient_start,
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"fill": {
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"type": "linear",
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"coords": {
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"x1": 0,
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"y1": 0,
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"x2": 0,
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"y2": canvas_height - gradient_start
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},
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"colorStops": [
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{"offset": 0, "color": f"rgba({top_color[0]},{top_color[1]},{top_color[2]},0.8)"},
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{"offset": 1, "color": f"rgba({bottom_color[0]},{bottom_color[1]},{bottom_color[2]},0.95)"}
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]
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},
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"selectable": False,
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"evented": False,
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}
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def create_text_object(
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self,
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text: str,
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left: int,
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top: int,
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font_size: int = 24,
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font_family: str = "Arial",
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fill: str = "#000000",
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font_weight: str = "normal",
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text_align: str = "left",
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**kwargs
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) -> Dict[str, Any]:
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"""
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创建文本对象
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Args:
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text: 文本内容
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left: 左边距
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top: 上边距
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font_size: 字体大小
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font_family: 字体
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fill: 填充颜色
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font_weight: 字重
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text_align: 对齐方式
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"""
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obj = {
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"type": "text",
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"version": self.FABRIC_VERSION,
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"left": left,
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"top": top,
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"text": text,
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"fontSize": font_size,
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"fontFamily": font_family,
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"fill": fill,
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"fontWeight": font_weight,
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"textAlign": text_align,
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"selectable": True,
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"evented": True,
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}
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obj.update(kwargs)
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return obj
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def create_text_objects(
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self,
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content: Dict[str, Any],
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canvas_width: int,
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canvas_height: int,
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gradient_start: int
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) -> List[Dict[str, Any]]:
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"""
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创建所有文本对象
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Args:
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content: 内容字典
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canvas_width: 画布宽度
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canvas_height: 画布高度
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gradient_start: 渐变起始位置
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"""
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objects = []
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margin = 40
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current_y = gradient_start + 60
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# 标题
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if content.get('title'):
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objects.append(self.create_text_object(
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text=content['title'],
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left=margin,
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top=current_y,
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font_size=48,
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font_weight="bold",
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fill="#333333"
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))
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current_y += 70
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# 副标题
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if content.get('subtitle'):
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objects.append(self.create_text_object(
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text=content['subtitle'],
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left=margin,
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top=current_y,
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font_size=28,
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fill="#666666"
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))
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current_y += 50
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# 价格
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if content.get('price'):
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price_text = f"¥{content['price']}"
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if content.get('original_price'):
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price_text += f" 原价¥{content['original_price']}"
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objects.append(self.create_text_object(
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text=price_text,
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left=margin,
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top=current_y,
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font_size=36,
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font_weight="bold",
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fill="#ff4444"
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))
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current_y += 60
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# 描述
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if content.get('description'):
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objects.append(self.create_text_object(
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text=content['description'],
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left=margin,
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top=current_y,
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font_size=20,
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fill="#888888"
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))
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return objects
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def create_rect_object(
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self,
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left: int,
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top: int,
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width: int,
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height: int,
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fill: str = "#ffffff",
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stroke: Optional[str] = None,
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stroke_width: int = 1,
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rx: int = 0,
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ry: int = 0,
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**kwargs
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) -> Dict[str, Any]:
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"""
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创建矩形对象
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Args:
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left: 左边距
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top: 上边距
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width: 宽度
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height: 高度
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fill: 填充颜色
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stroke: 边框颜色
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stroke_width: 边框宽度
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rx: 圆角 X
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ry: 圆角 Y
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"""
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obj = {
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"type": "rect",
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"version": self.FABRIC_VERSION,
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"left": left,
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"top": top,
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"width": width,
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"height": height,
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"fill": fill,
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"rx": rx,
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"ry": ry,
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}
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if stroke:
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obj["stroke"] = stroke
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obj["strokeWidth"] = stroke_width
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obj.update(kwargs)
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return obj
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# ========== 工具方法 ==========
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def _image_to_base64(self, image: 'Image.Image', format: str = 'PNG') -> str:
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"""将 PIL Image 转换为 base64"""
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buffer = BytesIO()
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image.save(buffer, format=format)
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return base64.b64encode(buffer.getvalue()).decode('utf-8')
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