From a11d325471be7ba147309f42148a9e16a6e82078 Mon Sep 17 00:00:00 2001
From: "B. Watson" <urchlay@slackware.uk>
Date: Sat, 27 Jul 2024 05:30:54 -0400
Subject: fonts: dotted box WIP. still not working.

---
 fonts/mkpsf.pl | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

(limited to 'fonts/mkpsf.pl')

diff --git a/fonts/mkpsf.pl b/fonts/mkpsf.pl
index 8166c8a..b6c5532 100644
--- a/fonts/mkpsf.pl
+++ b/fonts/mkpsf.pl
@@ -109,7 +109,7 @@ sub read_rom {
 # and 0x241b aka SYMBOL FOR ESCAPE).
 sub setup_map {
 	our @map = (
-			0x0000,
+			0x0000, # dotted-box (from char0.raw)
 			0x2665, # 0x00
 			0x2523, # 0x01
 			0x2503, # 0x02
@@ -434,8 +434,12 @@ setup_map();
 @scale2 = ();
 @scale3 = ();
 
-#$raw = read_rom("atarixl.rom", 0x2000, 128);
+# the dotted-box character has to come first in the BDF
+# font. or at least, the BDF has to say, up front, which
+# index (not unicode codepoint!) is the "default char", and
+# most fonts seem to use index 0 for this.
 $raw = read_rom("char0.raw", 0, 1);
+
 $raw .= read_rom("atarixl.rom", 0x2200, 32);
 $raw .= read_rom("atarixl.rom", 0x2000, 32);
 $raw .= read_rom("atarixl.rom", 0x2100, 32);
@@ -456,9 +460,7 @@ $raw .= read_rom("xe_arabic.rom", 0x2000+8*0x4f, 9);
 $raw .= read_rom("xe_arabic.rom", 0x2000+8*0x59, 2);
 $raw .= read_rom("xe_arabic.rom", 0x2000+8*0x60, 27);
 $raw .= read_rom("xe_arabic.rom", 0x2000+8*0x7f, 1);
-#warn length($raw) / 8;
-##$raw = read_rom("arabicxe.rom", 0x2000, 128);
-#$cnt = 0x9a;
+
 $cnt = 0;
 while($raw =~ /(.{8})/gc) {
 	my @bytes;
@@ -489,10 +491,16 @@ while(<DATA>) {
 #warn "(padding to 256 characters)\n" unless $cnt >= 256;
 #warn "(padding to 512 characters)\n" unless $cnt >= 512;
 
+# 512 glyphs is the max for a PSF font. There can be more
+# *codepoints*, because the Unicode directory allows the same
+# glyph to represent multiple codepoints (e.g. space and
+# non-breaking space).
 if($cnt > 512) {
-	die "$0: too many characters ($cnt > 512)";
+	die "$0: too many glyphs ($cnt > 512)";
 }
 
+# The kernel refuses to load a font that isn't exactly
+# 256 or 512 glyphs, so we have to pad with junk glyphs.
 while($cnt < 512) {
 	my $fake = "%\nUnicode: [0000];\nBitmap: ";
 	push @scale1, $fake . (("-" x 8) x 8) . "\n";
-- 
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