Add generate_fonts.py

Add code to generate 4k textures holding a bunch of unicode characters.
Add unicode blocks for English, Japanese, Chinese, and Korean.

Embed GNU's excellent Unifont ttf, which I use to generate these
textures. The license is included under $filename.LICENSE.

1 files changed, 81 insertions, 0 deletions

diff --git a/generate_fonts.py b/generate_fonts.py
new file mode 100644
index 0000000..0b9a4fd
--- /dev/null
+++ b/generate_fonts.py
@@ -0,0 +1,81 @@
+#!/usr/bin/env python3
+
+from PIL import Image, ImageFont, ImageDraw
+
+import math
+
+# Use a power of 2 pixels per character so we can evenly divide the plane.
+font_pixels = 64
+font = ImageFont.truetype("unifont-15.0.01.ttf", font_pixels)
+
+n_rows = 64
+n_cols = 128
+
+def allow_range(allowlist, lo, hi):
+    for i in range(lo, hi + 1):
+        allowlist.add(i)
+def ban_range(allowlist, lo, hi):
+    for i in range(lo, hi + 1):
+        allowlist.remove(i)
+allowlist = set()
+# ASCII
+allow_range(allowlist, 32, 126)
+# Latin-1 supplement
+allow_range(allowlist, 0x00A1, 255)
+# Latin extended-A
+allow_range(allowlist, 0x0100, 0x017F)
+# Latin extended-B
+allow_range(allowlist, 0x0180, 0x024F)
+# Spacing modifier letters
+allow_range(allowlist, 0x0250, 0x02AF)
+# Greek and Coptic
+allow_range(allowlist, 880, 1023)
+ban_range(allowlist, 0x0378, 0x03a2)
+# Cyrillic
+allow_range(allowlist, 0x0400, 0x04FF)
+# Currency symbols
+allow_range(allowlist, 0x20A0, 0x20C0)
+
+# Japanese
+# Punctuation
+allow_range(allowlist, 0x3000, 0x303F)
+# Hiragana
+allow_range(allowlist, 0x3041, 0x30FF)
+ban_range(allowlist, 0x3097, 0x3098)
+# Katakana
+allow_range(allowlist, 0x30A0, 0x30FF)
+# CJK Unified Ideographs (Kanji)
+allow_range(allowlist, 0x4E00, 0x9FFF)
+# CJK Unified Ideographs extension A (rare Kanji)
+allow_range(allowlist, 0x3400, 0x4dbf)
+
+# Korean
+allow_range(allowlist, 0x1100, 0x11FF)
+allow_range(allowlist, 0xAC00, 0xD7A3)
+
+max_char = max(allowlist)
+total_rows = math.ceil(max_char / n_cols)
+print("total rows {}".format(total_rows))
+total_textures = math.ceil(total_rows / n_rows)
+print("total textures {}".format(total_textures))
+
+for nth_texture in range(0, total_textures):
+    # Create a 4K grayscale ("L") image
+    image = Image.new(mode="L", size=(4096,4096), color=255)
+    draw = ImageDraw.Draw(image)
+
+    row_begin = nth_texture * n_rows
+
+    for row in range(row_begin, row_begin + n_rows):
+        line = ""
+        for col in range(0, n_cols):
+            # Generate the unicode character for this spot.
+            n = row * n_cols + col
+            if n in allowlist:
+                line += chr(n)
+            else:
+                line += " "
+        draw.text((0, (row - row_begin) * font_pixels), line, font=font)
+
+    image.save("font-%01d.png" % nth_texture)
+