re: crack the UI layout record — the retail UI rebuilds from the disc

Each UI sprite <name>.t32 ships with a <name>.rat companion, and that companion
is the layout record: big-endian u32, a 1280x720 design space at 0x18, and a
placement block of scaleX/scaleY/tint/X/Y. Animated elements repeat the block
with a trailing time field (keyframes); an 'opt ' tag carries a length-prefixed
link to the focused-state record.

Verified in that order, records first: across the four pause buttons exactly one
field varies, stepping 268/338/408/478 at a constant 70px pitch with X fixed at
226; the three items visible in a screenshot of the running game measure
346.0/415.5/485.5, mapping onto those numbers under one constant offset to
within 0.5px. The tutorial build's records are outright framebuffer coordinates,
and compositing its sprites there reproduces the screenshot pixel-accurately.

Also records two mistakes the A/B caught, since a static-only reading would have
shipped both: texture width does not identify a language (Japanese fits English
widths), and the in-mission and tutorial pause menus are separate sprite sets
rather than one set re-packed into slots.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

crates/sylpheed-formats/examples/ui_screen.rs

@@ -0,0 +1,55 @@
+//! Scratch analysis: inventory one UI screen's pak — every entry, and for RATC
+//! entries the children they bundle. Optionally write an entry's decompressed
+//! bytes out for hex inspection.
+//!
+//! Run: cargo run -p sylpheed-formats --example ui_screen -- <PAK> [--dump 0xHASH out.bin]
+
+use sylpheed_formats::pak::{self, PakArchive};
+use sylpheed_formats::ratc;
+
+fn main() {
+    let mut args = std::env::args().skip(1);
+    let pak = args.next().expect("usage: ui_screen <pak> [--dump 0xHASH out.bin]");
+    let arc = PakArchive::open(&pak).expect("open pak");
+
+    let rest: Vec<String> = args.collect();
+    if rest.first().map(|s| s == "--dump").unwrap_or(false) {
+        let h = u32::from_str_radix(rest[1].trim_start_matches("0x"), 16).unwrap();
+        let bytes = arc.read_by_hash(h).expect("entry present").expect("decompress");
+        std::fs::write(&rest[2], &bytes).unwrap();
+        println!("wrote {} bytes to {}", bytes.len(), rest[2]);
+        return;
+    }
+
+    if rest.first().map(|s| s == "--child").unwrap_or(false) {
+        // --child 0xHASH <child-name> <out>: carve one RATC child out by its
+        // listed offset/size, so a 165-byte layout record can be hexdumped alone.
+        let h = u32::from_str_radix(rest[1].trim_start_matches("0x"), 16).unwrap();
+        let bytes = arc.read_by_hash(h).expect("entry present").expect("decompress");
+        let kids = ratc::parse(&bytes).expect("ratc");
+        let k = kids.iter().find(|k| k.name == rest[2]).expect("child not found");
+        std::fs::write(&rest[3], &bytes[k.offset..k.offset + k.size]).unwrap();
+        println!("wrote {} B ({} @ {:#x}) to {}", k.size, k.name, k.offset, rest[3]);
+        return;
+    }
+
+    println!("{pak}: {} entries", arc.len());
+    for e in arc.entries() {
+        let Ok(bytes) = arc.read(e) else {
+            println!("  {:08x}  <decompress failed>", e.name_hash);
+            continue;
+        };
+        let label = pak::inner_format_label(&bytes);
+        println!("  {:08x}  {:>9} B  {}", e.name_hash, bytes.len(), label);
+        if ratc::is_ratc(&bytes) {
+            if let Some(kids) = ratc::parse(&bytes) {
+                for k in &kids {
+                    println!("        - {:<40} {:>9} B  {}", k.name, k.size, k.kind);
+                }
+                if kids.is_empty() {
+                    println!("        (no children found)");
+                }
+            }
+        }
+    }
+}