From: r1w1s1 <r1w1s1@fastmail.com>
Date: Wed, 22 Apr 2026
Subject: Fix SGR parameter consumption for truecolor sequences

SGR 38/48 can take either `;5;N` (256-color) or `;2;R;G;B` (truecolor).
The old code assumed ;5;N and always skipped 2 params, so `;2;R;G;B`
caused R, G, B to be reinterpreted as SGR codes, producing garbage
attributes. Handle both forms and skip the correct number of params.
Truecolor values are not rendered (ncurses pair limitation) but are
now consumed cleanly.
---
--- a/mtm.c
+++ b/mtm.c
@@ -449,7 +449,11 @@
         case 35:  fg = COLOR_MAGENTA;                         doc = do8;   break;
         case 36:  fg = COLOR_CYAN;                            doc = do8;   break;
         case 37:  fg = COLOR_WHITE;                           doc = do8;   break;
-        case 38:  fg = P0(i+1) == 5? P0(i+2) : s->fg; i += 2; doc = do256; break;
+        case 38:
+            if      (P0(i+1) == 5) { fg = P0(i+2); i += 2; doc = do256; }
+            else if (P0(i+1) == 2) { i += 4; }
+            else                     i += 1;
+            break;
         case 39:  fg = -1;                                    doc = true;  break;
         case 40:  bg = COLOR_BLACK;                           doc = do8;   break;
         case 41:  bg = COLOR_RED;                             doc = do8;   break;
@@ -459,7 +463,11 @@
         case 45:  bg = COLOR_MAGENTA;                         doc = do8;   break;
         case 46:  bg = COLOR_CYAN;                            doc = do8;   break;
         case 47:  bg = COLOR_WHITE;                           doc = do8;   break;
-        case 48:  bg = P0(i+1) == 5? P0(i+2) : s->bg; i += 2; doc = do256; break;
+        case 48:
+            if      (P0(i+1) == 5) { bg = P0(i+2); i += 2; doc = do256; }
+            else if (P0(i+1) == 2) { i += 4; }
+            else                     i += 1;
+            break;
         case 49:  bg = -1;                                    doc = true;  break;
         case 90:  fg = COLOR_BLACK;                           doc = do16;  break;
         case 91:  fg = COLOR_RED;                             doc = do16;  break;