调整轮廓算法中是否为像素点的判断逻辑

src/pixel_font_builder/opentype.py

@@ -118,7 +118,7 @@ def _create_outlines(glyph_data: list[list[int]], px_to_units: int) -> list[list
     point_group_list = []
     for y, glyph_data_row in enumerate(glyph_data):
         for x, alpha in enumerate(glyph_data_row):
-            if alpha > 0:
+            if alpha != 0:
                 new_point_group = {(x, y)}
                 for i, point_group in enumerate(reversed(point_group_list)):
                     # 遍历方向为右下，因此只需检查左上