Phase3: 三平台封面图生成

- cover_generator.py: Pillow生成知乎/微信/小红书封面图（渐变背景+标题）
- 知乎 1200×630 蓝调, 微信 900×500 绿调, 小红书 1080×1440 红调
- creator.py 流水线增加 cover_generator 作为最终回退
- db_helper.py 新增 save_cover_to_article
- main.py 挂载 /automation/images 静态目录
- articles.py preview 接口返回 images 字段
- topics.html 预览dialog展示封面图

platform/backend/app/api/articles.py

@@ -138,7 +138,7 @@ def preview_article(topic_id: str, platform: str = "zhihu", current_user: User =
     article = db.query(Article).filter(Article.id == article_id).first()
     if not article or not article.html_content:
         raise HTTPException(status_code=404, detail=f"Article not found for {topic_id} on {platform}")
-    return {"topic_id": topic_id, "platform": platform, "html": article.html_content}
+    return {"topic_id": topic_id, "platform": platform, "html": article.html_content, "images": article.images or {}}
 
 @router.put("/{topic_id}/content")
 def update_article_content(

platform/backend/app/main.py

@@ -95,6 +95,13 @@ app.include_router(platform_config.router)
 app.include_router(collector_mgmt.router)
 app.include_router(assistant.router)
 
+# 挂载自动生成的图片（必须先于前端根挂载）
+PROJECT_ROOT_DIR = Path(__file__).parent.parent.parent.parent
+AUTOMATION_IMAGES_DIR = PROJECT_ROOT_DIR / "automation" / "images"
+if AUTOMATION_IMAGES_DIR.exists():
+    app.mount("/automation/images", StaticFiles(directory=str(AUTOMATION_IMAGES_DIR)), name="images")
+    logger.info(f"Images mounted at /automation/images from {AUTOMATION_IMAGES_DIR}")
+
 # 挂载前端
 FRONTEND_DIR = Path(__file__).parent.parent.parent / "frontend"
 if FRONTEND_DIR.exists() and (FRONTEND_DIR / "index.html").exists():

platform/frontend/topics.html

@@ -163,6 +163,9 @@
                     </div>
                 </div>
                 <div style="width:100%;">
+                    <div v-if="!editing && previewImages[previewPlatform] && previewImages[previewPlatform].cover" style="margin-bottom:16px; border:1px solid #ebeef5; border-radius:8px; overflow:hidden; text-align:center;">
+                        <img :src="'/' + previewImages[previewPlatform].cover" alt="封面图" style="max-width:100%; max-height:360px; object-fit:contain;" @error="$event.target.style.display='none'" />
+                    </div>
                     <div v-if="!editing" class="preview-body" style="border:1px solid #ebeef5; border-radius:8px; background:#fff; padding:20px; width:100%; line-height:1.8;" v-html="currentPreviewBody"></div>
                     <div v-else ref="editor" contenteditable="true" style="min-height:300px; height:68vh; border:1px solid #409eff; border-radius:8px; background:#fff; padding:20px; overflow-y:auto; width:100%; line-height:1.8; outline:none; box-shadow:0 0 0 2px rgba(64,158,255,0.2);" @input="editContent = $event.target.innerHTML"></div>
                 </div>
@@ -196,7 +199,7 @@ const TopicsApp = {
             stats: { total: 0, pending: 0, review: 0, ready: 0, published: 0, today: 0 },
             topics: [], allTopics: [], todayTopics: [], todayCount: 0,
             previewVisible: false, previewTopic: null, previewFullscreen: false,
-            previewPlatform: 'zhihu', platformContents: {}, editing: false, editContent: '',
+            previewPlatform: 'zhihu', platformContents: {}, previewImages: {}, editing: false, editContent: '',
             publishDialogVisible: false, publishTopic: null,
             publishPlatforms: { zhihu: true, wechat: true, xiaohongshu: true },
             publishing: false,
@@ -317,14 +320,14 @@ const TopicsApp = {
             } catch (error) { this.$message.error(`批量审查失败: ${error.message}`); }
         },
         async openPreview(topic) {
-            this.previewTopic = topic; this.previewPlatform = 'zhihu'; this.previewVisible = true; this.platformContents = {};
+            this.previewTopic = topic; this.previewPlatform = 'zhihu'; this.previewVisible = true; this.platformContents = {}; this.previewImages = {};
             const token = this.getToken();
             if (!token) return;
             const platforms = ['zhihu', 'wechat', 'xiaohongshu'];
             const names = { zhihu: '知乎', wechat: '微信公众号', xiaohongshu: '小红书' };
             await Promise.all(platforms.map(p =>
                 fetch(`/api/articles/${topic.id}/preview?platform=${p}`, { headers: { 'Authorization': 'Bearer ' + token } })
-                    .then(r => r.ok ? r.json() : null).then(d => { if (d && d.html) this.platformContents[p] = d.html; }).catch(e => { console.error(`加载${p}预览失败:`, e); this.$message.error(`加载${names[p]}预览失败`); })
+                    .then(r => r.ok ? r.json() : null).then(d => { if (d && d.html) { this.platformContents[p] = d.html; if (d.images) this.previewImages[p] = d.images; } }).catch(e => { console.error(`加载${p}预览失败:`, e); this.$message.error(`加载${names[p]}预览失败`); })
             ));
         },
         togglePreviewFullscreen() {

scripts/cover_generator.py

@@ -0,0 +1,199 @@
+#!/usr/bin/env python3
+"""
+封面图生成器：为三平台文章生成文字封面图
+
+依赖: Pillow + Noto Sans CJK 字体
+用法: python3 scripts/cover_generator.py --topic-id A07
+"""
+
+import argparse, datetime, json, logging, sys, os
+from pathlib import Path
+from typing import Dict, Optional
+from PIL import Image, ImageDraw, ImageFont
+
+PROJECT_ROOT = Path(__file__).parent.parent
+sys.path.insert(0, str(PROJECT_ROOT))
+sys.path.insert(0, str(PROJECT_ROOT / "platform" / "backend"))
+
+from db_helper import get_topic_by_id
+
+LOGS_DIR = PROJECT_ROOT / "automation" / "logs"
+OUTPUT_DIR = PROJECT_ROOT / "automation" / "images" / "generated"
+TODAY = datetime.datetime.now().strftime("%Y-%m-%d")
+
+logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s',
+                    handlers=[logging.FileHandler(LOGS_DIR / f"cover_{TODAY}.log"), logging.StreamHandler()])
+logger = logging.getLogger(__name__)
+
+# Find a suitable CJK font
+_FONT_CANDIDATES = [
+    "/usr/share/fonts/google-noto-cjk/NotoSansCJK-Bold.ttc",
+    "/usr/share/fonts/google-noto-cjk/NotoSansCJK-Medium.ttc",
+    "/usr/share/fonts/google-noto-cjk/NotoSansCJK-Regular.ttc",
+    "/usr/share/fonts/opentype/noto/NotoSansCJK-Bold.ttc",
+    "/usr/share/fonts/truetype/noto/NotoSansCJK-Bold.ttc",
+]
+_FONT_PATH = None
+for fp in _FONT_CANDIDATES:
+    if Path(fp).exists():
+        _FONT_PATH = fp
+        break
+
+if not _FONT_PATH:
+    import subprocess
+    r = subprocess.run(["fc-match", "-f", "%{file}", "sans:lang=zh"], capture_output=True, text=True)
+    if r.returncode == 0 and Path(r.stdout.strip()).exists():
+        _FONT_PATH = r.stdout.strip()
+
+COVER_SIZES = {
+    "zhihu": (1200, 630),
+    "wechat": (900, 500),
+    "xiaohongshu": (1080, 1440),
+}
+
+PLATFORM_COLORS = {
+    "zhihu": { "bg_start": "#0066cc", "bg_end": "#004d99", "title": "#ffffff", "accent": "#66b3ff", "watermark": "知乎专栏" },
+    "wechat": { "bg_start": "#07c160", "bg_end": "#06ad56", "title": "#ffffff", "accent": "#b3ffd9", "watermark": "微信公众号" },
+    "xiaohongshu": { "bg_start": "#ff2442", "bg_end": "#cc1a35", "title": "#ffffff", "accent": "#ffb3c1", "watermark": "小红书" },
+}
+
+
+def _get_font(size: int):
+    if _FONT_PATH:
+        return ImageFont.truetype(_FONT_PATH, size)
+    return ImageFont.load_default()
+
+
+def _wrap_text(text: str, max_chars: int = 6) -> str:
+    """Split long title into lines"""
+    lines = []
+    while text:
+        if len(text) <= max_chars:
+            lines.append(text)
+            break
+        idx = text.rfind("，", 0, max_chars + 1)
+        if idx <= 0:
+            idx = text.rfind(" ", 0, max_chars + 1)
+        if idx <= 0:
+            idx = max_chars
+        lines.append(text[:idx])
+        text = text[idx:]
+    return "\n".join(lines)
+
+
+def generate_cover(topic_id: str, platform: str) -> Optional[str]:
+    """Generate cover image for a topic on a specific platform"""
+    topic = get_topic_by_id(topic_id)
+    if not topic:
+        logger.error(f"Topic {topic_id} not found")
+        return None
+
+    title = topic.get("title", "")
+    if not title:
+        logger.warning(f"Topic {topic_id} has no title")
+        return None
+
+    size = COVER_SIZES.get(platform)
+    if not size:
+        logger.error(f"Unknown platform: {platform}")
+        return None
+
+    colors = PLATFORM_COLORS[platform]
+    w, h = size
+    img = Image.new("RGB", (w, h))
+    draw = ImageDraw.Draw(img)
+
+    for y in range(h):
+        r = y / h
+        for c in range(3):
+            start = int(colors["bg_start"][1:3], 16) if c == 0 else (int(colors["bg_start"][3:5], 16) if c == 1 else int(colors["bg_start"][5:7], 16))
+            end = int(colors["bg_end"][1:3], 16) if c == 0 else (int(colors["bg_end"][3:5], 16) if c == 1 else int(colors["bg_end"][5:7], 16))
+            val = int(start + (end - start) * r)
+            color = list(img.getpixel((0, y)) if y > 0 else (0, 0, 0))
+            color[c] = val
+            img.putpixel((0, y), tuple(color))
+    for x in range(1, w):
+        color = img.getpixel((0, y))
+        draw.line([(x, y), (x, y)], fill=color)
+
+    if platform == "xiaohongshu":
+        title_font_size = 56
+        wrapped = _wrap_text(title, max_chars=7)
+        font = _get_font(title_font_size)
+        lines = wrapped.split("\n")
+        total_h = len(lines) * (title_font_size + 20)
+        start_y = (h - total_h) // 2 - 40
+        for i, line in enumerate(lines):
+            bbox = draw.textbbox((0, 0), line, font=font)
+            tw = bbox[2] - bbox[0]
+            x = (w - tw) // 2
+            y_pos = start_y + i * (title_font_size + 20)
+            draw.text((x, y_pos), line, fill=colors["title"], font=font)
+
+        font_small = _get_font(24)
+        wm = colors["watermark"]
+        bbox = draw.textbbox((0, 0), wm, font=font_small)
+        ww = bbox[2] - bbox[0]
+        draw.text(((w - ww) // 2, h - 80), wm, fill=colors["accent"], font=font_small)
+    else:
+        title_font_size = 52 if platform == "wechat" else 64
+        font = _get_font(title_font_size)
+        bbox = draw.textbbox((0, 0), title, font=font)
+        tw = bbox[2] - bbox[0]
+        if tw > w - 120:
+            wrapped = _wrap_text(title, max_chars=8)
+            lines = wrapped.split("\n")
+            total_h = len(lines) * (title_font_size + 16)
+            start_y = (h - total_h) // 2
+            for i, line in enumerate(lines):
+                bbox2 = draw.textbbox((0, 0), line, font=font)
+                tw2 = bbox2[2] - bbox2[0]
+                x = (w - tw2) // 2
+                draw.text((x, start_y + i * (title_font_size + 16)), line, fill=colors["title"], font=font)
+        else:
+            x = (w - tw) // 2
+            draw.text((x, h // 2 - title_font_size), title, fill=colors["title"], font=font)
+
+        font_small = _get_font(20)
+        wm = colors["watermark"]
+        bbox = draw.textbbox((0, 0), wm, font=font_small)
+        ww = bbox[2] - bbox[0]
+        draw.text((w - ww - 20, h - 40), wm, fill=colors["accent"], font=font_small)
+
+    out_dir = OUTPUT_DIR / TODAY
+    out_dir.mkdir(parents=True, exist_ok=True)
+    out_path = out_dir / f"cover_{platform}_{topic_id}.png"
+    img.save(out_path, "PNG")
+    relative_path = f"automation/images/generated/{TODAY}/cover_{platform}_{topic_id}.png"
+    logger.info(f"Cover saved: {out_path}")
+    return relative_path
+
+
+def update_article_image(topic_id: str, platform: str, image_path: str):
+    """Save cover path to Article.images JSON field"""
+    try:
+        from db_helper import save_cover_to_article
+        save_cover_to_article(topic_id, platform, image_path)
+    except Exception as e:
+        logger.warning(f"Failed to update article image in DB: {e}")
+
+
+def main():
+    parser = argparse.ArgumentParser(description="生成文章封面图")
+    parser.add_argument("--topic-id", required=True)
+    parser.add_argument("--platform", choices=["zhihu", "wechat", "xiaohongshu", "all"], default="all")
+    args = parser.parse_args()
+
+    platforms = ["zhihu", "wechat", "xiaohongshu"] if args.platform == "all" else [args.platform]
+    images = {}
+    for plat in platforms:
+        path = generate_cover(args.topic_id, plat)
+        if path:
+            images[plat] = path
+            update_article_image(args.topic_id, plat, path)
+    print(json.dumps(images, ensure_ascii=False))
+    logger.info(f"Generated covers for {args.topic_id}: {list(images.keys())}")
+
+
+if __name__ == "__main__":
+    main()

scripts/creator.py

@@ -103,10 +103,12 @@ def run_pipeline(topic_id: str = None) -> Dict:
             update_topic_status(tid, 'pending')
             return {"ok": False, "error": "writer step failed"}
 
-        # 4. 配图生成（AI版，失败时回退PIL版）
+        # 4. 配图生成（AI版 → PIL版 → 封面文字版）
         image_ok = run_step("ai_image_generator.py", tid)
         if not image_ok:
             image_ok = run_step("image_generator.py", tid)
+        if not image_ok:
+            image_ok = run_step("cover_generator.py", tid)
 
         # 5. 合规优化（自动审核并标记为「待发布」）
         if not run_optimizer_step(tid):

scripts/db_helper.py

@@ -259,6 +259,27 @@ def save_article(topic_id: str, platform: str, html_content: str, db: Optional[S
         if close_db:
             db.close()
 
+def save_cover_to_article(topic_id: str, platform: str, cover_path: str, db: Optional[Session] = None):
+    """保存封面图路径到 article.images 字段"""
+    close_db = False
+    if db is None:
+        db = SessionLocal()
+        close_db = True
+    try:
+        from app.models import Article
+        article_id = f"{platform}_{topic_id}"
+        article = db.query(Article).filter(Article.id == article_id).first()
+        if article:
+            images = article.images or {}
+            images["cover"] = cover_path
+            article.images = images
+            db.commit()
+    except Exception:
+        db.rollback()
+    finally:
+        if close_db:
+            db.close()
+
 def get_article(topic_id: str, platform: str, db: Optional[Session] = None) -> Optional[Dict]:
     """从 articles 表获取文章 HTML"""
     close_db = False