From 64e63f5cf3fdc657db54dffe2bd8c8b2761f7fe2 Mon Sep 17 00:00:00 2001
From: Isaiah Odhner <isaiahodhner@gmail.com>
Date: Tue, 19 Sep 2023 18:07:57 -0400
Subject: [PATCH] Optimize meta glyph rendering?

---
 src/textual_paint/canvas.py          | 12 ++++++++++--
 src/textual_paint/meta_glyph_font.py |  6 ++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/textual_paint/canvas.py b/src/textual_paint/canvas.py
index 6bf3138..b0c60f3 100644
--- a/src/textual_paint/canvas.py
+++ b/src/textual_paint/canvas.py
@@ -306,9 +306,17 @@ class Canvas(Widget):
             if x >= len(glyph_line) or x < 0:
                 return " "
             return glyph_line[x]
-        if ch in " ░▒▓█":
-            return ch
         match ch:
+            case " ":
+                return " "
+            case "░":
+                return "░"
+            case "▒":
+                return "▒"
+            case "▓":
+                return "▓"
+            case "█":
+                return "█"
             # These are now obsolete special cases of below fractional block character handling.
             # case "▄":
             #     return "█" if y >= magnification // 2 else " "
diff --git a/src/textual_paint/meta_glyph_font.py b/src/textual_paint/meta_glyph_font.py
index f53516a..93969d2 100644
--- a/src/textual_paint/meta_glyph_font.py
+++ b/src/textual_paint/meta_glyph_font.py
@@ -19,6 +19,11 @@ class MetaGlyphFont:
         """The height in characters of a meta-glyph."""
         self.covered_characters = covered_characters
         """The characters supported by this font."""
+
+        # EXCLUDE certain characters which are better handled by procedural glyph rendering.
+        for ch in " ░▒▓██▔🮂🮃▀🮄🮅🮆▇▆▅▄▃▂▁▏▎▍▌▋▊▉███🮋🮊🮉▐🮈🮇▕":
+            self.covered_characters = self.covered_characters.replace(ch, "")
+
         self.load()
 
     def load(self):
@@ -46,6 +51,7 @@ meta_glyph_fonts: dict[int, MetaGlyphFont] = {
     2: MetaGlyphFont(os.path.join(os.path.dirname(__file__), "fonts/NanoTiny/NanoTiny_v14_2x2.flf"), 2, 2, covered_characters),
     # 4: MetaGlyphFont(os.path.join(os.path.dirname(__file__), "fonts/NanoTiny/NanoTiny_v14_4x4.flf"), 4, 4, covered_characters),
     # TODO: less specialized (more practical) fonts for larger sizes
+    # Also ASCII-only fonts for --ascii-only mode
 }
 
 def largest_font_that_fits(max_width: int, max_height: int) -> MetaGlyphFont | None: