ModelTranslator: 新增 uv_preview.render_uv_png——PIL 绘 UV 线框 PNG

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Tools/ModelTranslator/uv_preview.py

@@ -0,0 +1,31 @@
+"""UV 线框观察图渲染：把 UV 多边形（归一化 0-1 坐标）画成 PNG 供人工查阅。
+在系统 Python（有 Pillow）中运行——Blender 自带 Python 无 PIL，故 UV 几何由
+bl_decimate 导出为 JSON，本模块负责绘制。"""
+from PIL import Image, ImageDraw
+
+
+def _to_px(u, v, size, pad):
+    """UV(0-1, 原点左下) -> 像素(原点左上)，含边距。"""
+    span = size - 2 * pad
+    x = pad + u * span
+    y = pad + (1.0 - v) * span   # V 轴翻转：图像 y 向下
+    return x, y
+
+
+def render_uv_png(polygons, out_png, size=1024, pad=8,
+                  line=(30, 30, 30, 255), fill=(80, 140, 220, 64)):
+    """polygons: [[[u,v], ...], ...] 每个多边形一组 UV 顶点。
+    白底 + 半透明填充 + 深色线框；写 PNG 到 out_png，返回 out_png。"""
+    base = Image.new("RGBA", (size, size), (255, 255, 255, 255))
+    overlay = Image.new("RGBA", (size, size), (0, 0, 0, 0))
+    draw = ImageDraw.Draw(overlay, "RGBA")
+    for poly in polygons:
+        pts = [_to_px(u, v, size, pad) for (u, v) in poly]
+        if len(pts) >= 3:
+            draw.polygon(pts, fill=fill)
+    for poly in polygons:
+        pts = [_to_px(u, v, size, pad) for (u, v) in poly]
+        if len(pts) >= 2:
+            draw.line(pts + pts[:1], fill=line, width=1)
+    Image.alpha_composite(base, overlay).convert("RGB").save(out_png, "PNG")
+    return out_png