improve NITRAC doc cover

NLI-doc-template.typ

@@ -49,13 +49,17 @@
 #let cover(
   title: none,        // 主标题(中文)
   title-en: none,     // 主标题(英文,Source Code Pro 自行排版)
-  subtitle: none,     // 副标题
+  subtitle: none,     // 兼容旧调用:英文分册题名
+  sub_title: none,    // 中文分册题名
+  sub_title_en: none, // 英文分册题名
+  subtitle_en: none,  // 兼容旧调用:英文分册题名
   logo: none,         // 图片路径,如 image("logo.png")
   number: none,       // 文档编号
   author: none,       // 作者(可为单个字符串或数组)
   classification: none, // 密级,如 "内部"、"秘密"
   info: (:),          // 附加信息字典,如 (学号: "123", 指导教师: "张三")
   date: none,         // 日期
+  part-info: none,    // 兼容旧调用:分册题名
   fill: white,        // 封面背景色
   decorate: true,     // 是否绘制天蓝/暖橙网格装饰色块
 ) = {
@@ -165,6 +169,53 @@
       let title-rows = cn-rows + en-rows
       let title-end-y = (7 + title-rows) * unit + en-gap
 
+      let part-title-text = if sub_title != none { sub_title } else { none }
+      let part-title-en = if sub_title_en != none {
+        sub_title_en
+      } else if subtitle_en != none {
+        subtitle_en
+      } else {
+        subtitle
+      }
+      let part-box = if part-title-text != none or part-title-en != none or part-info != none {
+        let part-lines = ()
+        if part-title-text != none {
+          part-lines.push(text(
+            font: (cover-cjk, cover-latin), size: 18pt, fill: black,
+          )[#part-title-text])
+        }
+        if part-title-en != none {
+          let part-en = text(
+            font: (cover-latin, cover-cjk), size: 18pt, fill: black,
+          )[#part-title-en]
+          let part-en-inner = {
+            set par(leading: 0.3em)
+            part-en
+          }
+          part-lines.push(box(
+            width: 10.5cm - unit - 0.0 * unit,
+            part-en-inner,
+          ))
+        }
+        if part-lines.len() == 0 and part-info != none {
+          part-lines.push(text(
+            font: (cover-cjk, cover-latin), size: 18pt, fill: black,
+          )[#part-info])
+        }
+        let part-value = stack(dir: ttb, spacing: 0.35 * unit, ..part-lines)
+        box(
+          width: 10.5cm - unit,
+          inset: (left: 0.25 * unit, right: 0.25 * unit),
+          align(left + top, part-value),
+        )
+      } else { none }
+      let part-y = title-end-y + 0.5 * unit
+      let part-height = if part-box != none { measure(part-box).height } else { 0pt }
+      if part-box != none {
+        place(top + left, dx: unit, dy: part-y, part-box)
+      }
+      let part-end-y = part-y + part-height
+
       let metadata = ()
       if number != none { metadata.push(("编号", number)) }
       if author != none {
@@ -177,7 +228,7 @@
         if value != none { metadata.push((str(key), value)) }
       }
       let marker-height = 2 * unit
-      let info-y = title-end-y + 0.45 * unit
+      let info-y = part-end-y + 0.45 * unit
 
       let cells = ()
       for (label, value) in metadata {
@@ -191,7 +242,9 @@
         )[#value])
       }
       let info-content = if metadata.len() > 0 {
-        box(width: 21cm - 1.5 * unit,
+        box(
+          width: 21cm - 8.5 * unit,
+          inset: (left: 0.25 * unit, right: 0.25 * unit),
           align(left + top, grid(
             columns: (auto, 1fr),
             column-gutter: 0.6em,
@@ -205,11 +258,7 @@
       // 左侧笔画与右侧笔画一样保持固定高度，不再随标题行数拉伸。
       // 标志在第七格独立收尾；下方长条依据文档信息的实际高度紧凑起笔。
       tri(0, 6, "tr", sky)
-      let strip-y = if metadata.len() > 0 {
-        info-y + info-height + 0.18 * unit
-      } else {
-        7 * unit
-      }
+      let strip-y = part-end-y + 0.18 * unit
       let strip-height = 29.7cm - strip-y
       place(top + left, dy: strip-y, polygon(
         fill: sky, stroke: none,
@@ -240,17 +289,23 @@
         )[signed]
         let signed-size = measure(signed-label)
         place(top + left,
-          dx: unit + signature-line-length - signed-size.width,
+          dx: unit,
           dy: meta-y + apex-y - signed-size.height - 0.04 * unit,
           signed-label)
 
         // 三角形保留在距页底七个单位的位置，作为独立的封面装饰。
         // 文档信息不再与三角形连线，而是跟随主标题实际高度，排列在标题正下方。
 
-        place(top + left, dx: 1.25 * unit, dy: info-y, info-content)
+        place(
+          top + left,
+          dx: unit + signature-line-length,
+          dy: meta-y + apex-y + 0.3 * unit,
+          info-content,
+        )
       }
+
+      tri(2, 6, "tl", sky)
     }
-    tri(2, 6, "tl", sky)
   }
 
   pagebreak(weak: true)