fix(client): 标签字体细化：阈值 128，店名细体

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -5,6 +5,16 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.51] - 2026-06-15
+
+### 改进
+- 标签打印字体细化：阈值调回 128，店名改细体，商品名保持粗体
+
+## [1.0.50] - 2026-06-15
+
+### 改进
+- 标签打印字体更清晰：采用 2× 超采样渲染，消除热敏打印时反锯齿导致的模糊笔划
+
 ## [1.0.49] - 2026-06-15
 
 ### 改进

client/lib/core/utils/print_util_stub.dart

@@ -189,7 +189,8 @@ double _fitFont(String s, double maxW, double maxH, bool bold, double cap) {
   return size;
 }
 
-/// 用 dart:ui 把一张标签绘制成 320×160 位图（热敏标签实际尺寸 40×20mm @203dpi）。
+/// 用 dart:ui 把一张标签绘制成位图（热敏标签实际尺寸 40×20mm @203dpi）。
+/// 内部以 2× 超采样（640×320）绘制，转 TSPL 时再降采样，消除反锯齿模糊。
 /// 供 TSPL 裸发和预览渲染共用同一套画布逻辑，确保预览即实际输出。
 Future<ui.Image> _renderLabelBitmap({
   required String shop,
@@ -199,10 +200,13 @@ Future<ui.Image> _renderLabelBitmap({
   required String date,
   required Uint8List qrBytes,
 }) async {
-  const w = 320, h = 160; // 40×20mm @203dpi
+  const w = 320, h = 160; // 40×20mm @203dpi（逻辑尺寸）
+  const scale = 2;         // 2× 超采样，内部以 640×320 绘制
+  const sw = w * scale, sh = h * scale;
   final recorder = ui.PictureRecorder();
   final canvas = ui.Canvas(
-      recorder, ui.Rect.fromLTWH(0, 0, w.toDouble(), h.toDouble()));
+      recorder, ui.Rect.fromLTWH(0, 0, sw.toDouble(), sh.toDouble()));
+  canvas.scale(scale.toDouble(), scale.toDouble()); // 坐标系放大，后续坐标不变
   canvas.drawRect(ui.Rect.fromLTWH(0, 0, w.toDouble(), h.toDouble()),
       ui.Paint()..color = const ui.Color(0xFFFFFFFF));
 
@@ -236,8 +240,8 @@ Future<ui.Image> _renderLabelBitmap({
 
   final codeText = code.isNotEmpty ? '编号：$code' : '';
   final rows = <(String, double, bool)>[
-    if (shop.isNotEmpty)     (shop,    kShopSize,  true),
-    if (name.isNotEmpty)     (name,    nameSize,   true),
+    if (shop.isNotEmpty)     (shop,    kShopSize,  false), // 店名细体，突出商品名
+    if (name.isNotEmpty)     (name,    nameSize,   true),  // 商品名粗体
     if (codeText.isNotEmpty) (codeText, kSmallSize, false),
     if (degSpec.isNotEmpty)  (degSpec,  kSmallSize, false),
     if (date.isNotEmpty)     (date,     kSmallSize, false),
@@ -258,7 +262,7 @@ Future<ui.Image> _renderLabelBitmap({
     yy += r.$2 * kLineH + gap;
   }
 
-  return recorder.endRecording().toImage(w, h);
+  return recorder.endRecording().toImage(sw, sh); // 返回 2× 图（640×320）
 }
 
 /// 桌面端把「扁平标签」直接画成单色位图，TSPL BITMAP 裸发到热敏机。
@@ -279,11 +283,13 @@ Future<bool> _printFlatLabelThermal({
   debugPrint('[label] thermal printer = $printer');
   if (printer == null) return false;
 
+  // img 是 2× 超采样图（640×320）；TSPL 输出仍是 320×160
   const w = 320, h = 160;
   final img = await _renderLabelBitmap(
       shop: shop, name: name, code: code, degSpec: degSpec, date: date, qrBytes: qrBytes);
   final bd = await img.toByteData(format: ui.ImageByteFormat.rawRgba);
   final rgba = bd!.buffer.asUint8List();
+  final sw = img.width; // 640（2×宽）
 
   // 打包 TSPL（SIZE 用整数，避免固件不认小数导致多走纸）
   const wbytes = (w + 7) >> 3;
@@ -294,12 +300,18 @@ Future<bool> _printFlatLabelThermal({
   for (int yy = 0; yy < h; yy++) {
     final row = Uint8List(wbytes)..fillRange(0, wbytes, 0xFF); // 默认白 bit=1
     for (int xx = 0; xx < w; xx++) {
-      final i = (yy * w + xx) * 4;
-      final a = rgba[i + 3];
-      final lum = a < 128
-          ? 255.0
-          : 0.299 * rgba[i] + 0.587 * rgba[i + 1] + 0.114 * rgba[i + 2];
-      if (lum < 128) row[xx >> 3] &= ~(0x80 >> (xx & 7)); // 黑点 -> bit0
+      // 2×2 四像素平均后阈值，消除反锯齿模糊（阈值 160 = 偏灰的边缘算黑）
+      double lum = 0;
+      for (int dy = 0; dy < 2; dy++) {
+        for (int dx = 0; dx < 2; dx++) {
+          final i = ((yy * 2 + dy) * sw + (xx * 2 + dx)) * 4;
+          final a = rgba[i + 3];
+          lum += a < 128
+              ? 255.0
+              : 0.299 * rgba[i] + 0.587 * rgba[i + 1] + 0.114 * rgba[i + 2];
+        }
+      }
+      if (lum / 4 < 128) row[xx >> 3] &= ~(0x80 >> (xx & 7)); // 黑点 -> bit0
     }
     out.add(row);
   }