Revert "Improve shade character appearance"

This reverts commit c883a024ba2a58533fb5bea021fe6b3d2dfb11a2.

To maximize compatibility with the appearance in the standard.

kitty/fonts/box_drawing.py

@@ -613,19 +613,21 @@ def inner_corner(buf: BufType, width: int, height: int, which: str = 'tl', level
     draw_vline(buf, width, y1, y2, width // 2 + (xd * hgap), level)
 
 
-@supersampled()
 def shade(buf: BufType, width: int, height: int, light: bool = False, invert: bool = False) -> None:
-    x_size = width / 4
-    y_size = height / 8
-    pattern_segments = 4 if light else 2
-    for y in range(height):
-        y_segment = y / y_size
-        offset = y * width
-        for x in range(width):
-            segment = x/x_size + y_segment
-            section = int(segment) % pattern_segments
-            enabled = section == 1
-            if invert ^ enabled:
+    square_sz = max(1, width // 12)
+    number_of_rows = height // square_sz
+    number_of_cols = width // square_sz
+    nums = range(square_sz)
+
+    for r in range(number_of_rows):
+        for c in range(number_of_cols):
+            if invert ^ ((r % 2 != c % 2) or (light and r % 2 == 1)):
+                continue
+            for yr in nums:
+                y = r * square_sz + yr
+                offset = width * y
+                for xc in nums:
+                    x = c * square_sz + xc
                     buf[offset + x] = 255