fix(annotation): 标注图重排，8 个量全标注且不重叠

- 修复七眼三个横向量(单眼宽度/两眼间距/脸宽)叠在同一条眼睛线上的重叠问题，
  改为上下错开三个高度，各自虚线带箭头 + 紧贴标签
- 新增「全脸总高」标注：右侧竖向标尺(虚线双箭头，头顶→下巴)+ 标签
- 四庭(顶/上/中/下庭)仍在左侧各段中点
- 标签用全名：单眼宽度/两眼间距/脸宽/全脸总高
- 新增 tests/test_annotation.py 防回归

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

face_analysis/annotation.py

@@ -69,8 +69,20 @@ def draw_dashed_line_with_arrows(draw, x1, y1, x2, y2, color=LINE_COLOR,
         draw.line([p2, (ex, ey)], fill=color, width=LINE_WIDTH)
 
 
+def _text_size(draw, text, font):
+    bbox = draw.textbbox((0, 0), text, font=font)
+    return bbox[2] - bbox[0], bbox[3] - bbox[1]
+
+
 def create_annotated_image(image_bgr, measure_result):
-    """生成标注图层 PNG（透明底 RGBA，尺寸同原图）。返回 PIL.Image。"""
+    """生成标注图层 PNG（透明底 RGBA，尺寸同原图）。返回 PIL.Image。
+
+    布局（避免重叠）：
+    - 四庭水平分界线（渐变消失），四庭 cm 数值在**左侧**各段中点。
+    - **全脸总高**：右侧竖向标尺（虚线双箭头，头顶→下巴），标签在标尺左侧竖排。
+    - 七眼：单眼宽度 / 两眼间距 / 脸宽 三个量**上下错开三个高度**，
+      各自虚线带箭头 + 紧贴各自线条的标签，互不重叠。
+    """
     h, w = image_bgr.shape[:2]
     v = measure_result.vertical
 
@@ -86,41 +98,52 @@ def create_annotated_image(image_bgr, measure_result):
     draw = ImageDraw.Draw(canvas)
     font = _load_font()
 
-    # --- 2. 四庭 cm 数值（左侧） ---
+    # --- 2. 四庭 cm 数值（左侧，各段中点） ---
     court_labels = [
         ("顶庭", measure_result.top_cm),
         ("上庭", measure_result.upper_cm),
         ("中庭", measure_result.middle_cm),
         ("下庭", measure_result.lower_cm),
     ]
-    left_margin = 16
+    left_margin = 12
     for i, (label, cm_val) in enumerate(court_labels):
         y_mid = (ys[i] + ys[i + 1]) / 2 - FONT_SIZE / 2
         draw.text((left_margin, y_mid), f"{label} {cm_val:.2f}cm",
                   fill=LINE_COLOR, font=font)
 
-    # --- 3. 七眼标注（虚线箭头 + 上下穿插标签） ---
-    pts = measure_result.eyes["points"]
-    pc = measure_result.px_per_cm
-    eye_y = (pts["left_inner"][1] + pts["right_inner"][1]) / 2
+    # --- 3. 全脸总高：右侧竖向标尺（头顶→下巴，虚线双箭头） ---
+    top_y, chin_y = ys[0], ys[-1]
+    ruler_x = w - 30                              # 内移，使竖线与箭头完整可见
+    draw_dashed_line_with_arrows(draw, ruler_x, top_y, ruler_x, chin_y)
+    th_lines = ["全脸总高", f"{measure_result.face_total_cm:.2f}cm"]
+    th_w = max(_text_size(draw, t, font)[0] for t in th_lines)
+    th_x = ruler_x - 6 - th_w                     # 标签放标尺左侧，避免出界
+    th_y = (top_y + chin_y) / 2 - FONT_SIZE       # 竖向居中（两行）
+    for j, t in enumerate(th_lines):
+        draw.text((th_x, th_y + j * (FONT_SIZE + 3)), t, fill=LINE_COLOR, font=font)
 
-    def hline(p_left, p_right, label, cm_val, above):
-        y = eye_y
+    # --- 4. 七眼：上下错开三个高度，各自虚线箭头 + 标签 ---
+    pts = measure_result.eyes["points"]
+    eye_y = (pts["left_inner"][1] + pts["right_inner"][1]) / 2
+    vgap = FONT_SIZE + 12  # 行间距，保证标签放得下
+
+    def span(p_left, p_right, y, label, cm_val, label_above):
         draw_dashed_line_with_arrows(draw, p_left[0], y, p_right[0], y)
         text = f"{label} {cm_val:.2f}cm"
-        tx = (p_left[0] + p_right[0]) / 2
-        ty = y - FONT_SIZE - 4 if above else y + 4
-        bbox = draw.textbbox((0, 0), text, font=font)
-        tw = bbox[2] - bbox[0]
-        draw.text((tx - tw / 2, ty), text, fill=LINE_COLOR, font=font)
+        tw, _ = _text_size(draw, text, font)
+        tx = (p_left[0] + p_right[0]) / 2 - tw / 2
+        ty = y - FONT_SIZE - 3 if label_above else y + 3
+        draw.text((tx, ty), text, fill=LINE_COLOR, font=font)
 
-    # 眼宽（左眼，标签在上）、两眼间距（标签在下）、脸宽（标签在上）—— 上下穿插
-    hline(pts["left_outer"], pts["left_inner"],
-          "眼宽", measure_result.eye_width_cm, above=True)
-    hline(pts["left_inner"], pts["right_inner"],
-          "间距", measure_result.inter_eye_cm, above=False)
-    hline(pts["left_cheek"], pts["right_cheek"],
-          "脸宽", measure_result.face_width_cm, above=True)
+    # 单眼宽度（眼睛线，标签在上）
+    span(pts["left_outer"], pts["left_inner"], eye_y,
+         "单眼宽度", measure_result.eye_width_cm, label_above=True)
+    # 两眼间距（稍下一层，标签在线上方的空档）
+    span(pts["left_inner"], pts["right_inner"], eye_y + vgap,
+         "两眼间距", measure_result.inter_eye_cm, label_above=True)
+    # 脸宽（再下一层，标签在下）
+    span(pts["left_cheek"], pts["right_cheek"], eye_y + 2 * vgap,
+         "脸宽", measure_result.face_width_cm, label_above=False)
 
     return canvas