fix: Windows 图标支持多分辨率 RGBA 圆角，修复 ICO 只有 16x16 单帧的问题

tauri-app/src-tauri/icons/generate-icons.py

@@ -4,6 +4,8 @@
 from PIL import Image, ImageDraw
 import subprocess
 import os
+import struct
+import io
 
 # 配置
 LOGO_PATH = "../../public/assets/logo.png"
@@ -33,7 +35,8 @@ def generate_icon(size):
     # 加载并缩放 logo
     logo = Image.open(LOGO_PATH).convert("RGBA")
     logo_size = int(min(size) * LOGO_SCALE)
-    logo.thumbnail((logo_size, logo_size), Image.LANCZOS)
+    # 使用 resize 确保精确尺寸，避免 thumbnail 导致的尺寸偏差
+    logo = logo.resize((logo_size, logo_size), Image.LANCZOS)
 
     # 居中绘制 logo
     x = (size[0] - logo.width) // 2
@@ -43,6 +46,36 @@ def generate_icon(size):
     return bg
 
 
+def save_ico(images, sizes, filepath):
+    """手动构建多帧 ICO 文件（PIL 原生 save 不支持 append_images for ICO）"""
+    num_images = len(images)
+    # ICONDIR: Reserved(2) + Type(2) + Count(2)
+    header = struct.pack("<HHH", 0, 1, num_images)
+
+    offset = 6 + 16 * num_images
+    entries = []
+    data = b""
+
+    for img, size in zip(images, sizes):
+        buf = io.BytesIO()
+        img.save(buf, format="PNG")
+        png_bytes = buf.getvalue()
+
+        w = size if size < 256 else 0
+        h = size if size < 256 else 0
+        # ICONDIRENTRY: Width(1) + Height(1) + Colors(1) + Reserved(1) + Planes(2) + BPP(2) + Size(4) + Offset(4)
+        entry = struct.pack("<BBBBHHII", w, h, 0, 0, 1, 32, len(png_bytes), offset)
+        entries.append(entry)
+        data += png_bytes
+        offset += len(png_bytes)
+
+    with open(filepath, "wb") as f:
+        f.write(header)
+        for e in entries:
+            f.write(e)
+        f.write(data)
+
+
 def main():
     os.chdir(os.path.dirname(os.path.abspath(__file__)))
 
@@ -82,24 +115,10 @@ def main():
     )
     print("Generated icon.icns")
 
-    # 生成 ICO（Windows 需要多分辨率）
+    # 生成 ICO（Windows 需要多分辨率，保留 RGBA 透明通道实现圆角效果）
     ico_sizes = [16, 32, 48, 64, 128, 256]
-    ico_images = []
-    for s in ico_sizes:
-        img = generate_icon((s, s))
-        # ICO 需要 RGB 模式
-        if img.mode == "RGBA":
-            rgb = Image.new("RGB", img.size, (255, 255, 255))
-            rgb.paste(img, mask=img.split()[3])
-            ico_images.append(rgb)
-        else:
-            ico_images.append(img)
-
-    ico_images[0].save(
-        f"{OUTPUT_DIR}/icon.ico",
-        format="ICO",
-        sizes=[(s, s) for s in ico_sizes],
-    )
+    ico_images = [generate_icon((s, s)) for s in ico_sizes]
+    save_ico(ico_images, ico_sizes, f"{OUTPUT_DIR}/icon.ico")
     print("Generated icon.ico")
 
     # 清理临时目录