parse art once per request; inline the art font and set a dark color-scheme to stop the load flicker

inc/art.php

@@ -69,6 +69,43 @@ function ansi_html(string $file, bool $mirror = false): string
     return ansi_html_cells($raw, $mirror);
 }
 
+/**
+ * Plain-ASCII art as [lines of chars, lines of color-index bytes, color => index],
+ * or null with too many colors for a byte. One regex pass over the whole file;
+ * kept per request so the mirrored side doesn't parse it a second time.
+ */
+function ansi_parse_bytes(string $raw): ?array
+{
+    static $memo = [], $done = [];
+    $key = md5($raw);
+    if (array_key_exists($key, $done)) {
+        return $done[$key];
+    }
+    $index = ['' => 0];                       // color hex => byte (0 = uncolored)
+    $chars = [];
+    $masks = [];
+    $c = $m = '';
+    $cur = null;
+    foreach (preg_split('/(\e\[[0-9;]*m|\n)/', rtrim($raw, "\n"), -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY) as $part) {
+        if ($part === "\n") {                 // colors don't carry across lines
+            $chars[] = $c;
+            $masks[] = $m;
+            $c = $m = '';
+            $cur = null;
+        } elseif ($part[0] === "\e") {
+            // a handful of distinct codes repeated thousands of times: decode each once
+            $cur = $memo[$part . '|' . $cur] ??= ansi_color(explode(';', substr($part, 2, -1)), $cur);
+        } else {
+            $k = $index[$cur ?? ''] ??= count($index);
+            $c .= $part;
+            $m .= str_repeat(chr($k), strlen($part));
+        }
+    }
+    $chars[] = $c;
+    $masks[] = $m;
+    return $done[$key] = count($index) > 250 ? null : [$chars, $masks, $index];
+}
+
 /**
  * Fast path for plain-ASCII art (one byte per cell): each line becomes a
  * string of characters plus a parallel string of color indices, and every
@@ -81,30 +118,11 @@ function ansi_html_bytes(string $raw, bool $mirror): ?string
     $from ??= implode(array_map('chr', range(0, 255)));
     $to ??= "\xff" . str_repeat("\0", 255);
 
-    static $memo = [];
-    $index = ['' => 0];                       // color hex => byte (0 = uncolored)
-    $chars = [];
-    $masks = [];
-    foreach (explode("\n", rtrim($raw, "\n")) as $line) {
-        $c = '';
-        $m = '';
-        $cur = null;
-        foreach (preg_split('/(\e\[[0-9;]*m)/', $line, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY) as $part) {
-            if ($part[0] === "\e") {
-                // a handful of distinct codes repeated thousands of times: decode each once
-                $cur = $memo[$part . '|' . $cur] ??= ansi_color(explode(';', substr($part, 2, -1)), $cur);
-                continue;
-            }
-            $k = $index[$cur ?? ''] ??= count($index);
-            $c .= $part;
-            $m .= str_repeat(chr($k), strlen($part));
-        }
-        $chars[] = $c;
-        $masks[] = $m;
-    }
-    if (count($index) > 250) {
+    $parsed = ansi_parse_bytes($raw);
+    if ($parsed === null) {
         return null;
     }
+    [$chars, $masks, $index] = $parsed;
 
     $width = max(array_map('strlen', $chars) ?: [0]);
     foreach ($chars as $i => $c) {