[zxcheergo]

What and why

On a screen taller than 16:9, such as the iPhone Duo's (about 1.43:1), Breath of the Wild is shown as a 16:9 picture: stretched, or with bars. This adds an opt-in picture of the screen's own shape for this game.

• Host (dm/host/loader.c): DM_SCREEN_ASPECT=<width/height> (1.3 to 1.77) gives a game whose profile has screen_aspect on an output 1920 wide and as tall as the ratio asks (1.43 → 1920x1344, a 1280x896 layout space), written to the frame-step state page with the constants the stubs read. Launcher setting Picture shape; 0/unset is 16:9 and changes nothing.
• Profile (dm/games/01007EF00011E000/patches.py, duo_anchor.c):
  • the output and layout sizes, and the game's own 1280x720 conversions, follow the host's;
  • sead::PerspectiveProjection takes the vertical angle that keeps 16:9's sides in view and stores it, so shadow cascades and culling see the view as drawn (widening only sin/cos/tan left the ground black in patches); the camera's fovy getters and the HUD camera follow;
  • in Pane::Calculate, widgets at the 720 space's edges, and edge-anchored widgets listed by name and place from the layout files (dialog box, subtitles, location and boss names, logos), move out with the taller edges; full-screen backgrounds stretch, page frames grow once, side masks scale about the centre (the scope's circle stays round), the title art scales without stretching, and the map's scrolling cut-outs are left alone;
  • the title menu's two 480x720 backing halves are stretched together (scaled about the centre, the right half's inner edge had moved out 39 units and left a bright band);
  • full-screen captures and their copied rect follow the layout height in both capture classes (the second, main+0xf66118 / main+0xf66334, is an NPC dialog box's blurred backing: with the file's 720 it copied a rect 88 units below the moved box, and the box's part below the 720 edge showed black from beyond the screen), projected background textures map the whole height, the map's footprint trail keeps its 720-pane projection, and the camera rune's photo takes the screen's middle 16:9 band instead of the whole screen squeezed into its 854x480 picture.

The details, offsets and what each stub fixed are in the game note's new section (README) and in the comments next to each stub. duo_anchor.c is compiled into ANCHOR_WORDS with the command in the comment above them (rebuilding it from this source gives the same 2,357 words).

Related: #117 (Hades edge to edge, a general output size, parked) and #631 (bars filled with a blurred copy). This one keeps the game's 16:9 composition and adds picture above and below instead of filling or stretching.

Checked

• Tests: make -C dm/host/tests GAME=01007EF00011E000 run and make -C dm/gfx/tests GAME=01007EF00011E000 run on an M1 (all pass); dm/tools/tests test_docs, test_env_switches, test_launcher_settings, test_game_profile, test_settings, test_player_env; dm/tools/lint_python.py with .github/requirements/lint.txt (0 new). The C lint was not run here (no LLVM clang-tidy on this Mac): left to CI.
• Games run, with title ID and version: The Legend of Zelda: Breath of the Wild 01007EF00011E000 1.9.0 with both DLC, headless on the Mac.
  • On an earlier base, each route at DM_SCREEN_ASPECT=1.43 against the same route at 16:9 (screenshots compared row by row): the map and footprint mode at four zoom levels (every region of the trail at 0 offset), the inventory, system and options pages, the album and compendium, the three weapon wheels, the scope (zoomed), the camera rune with its shutter and save prompt, a memory cutscene with subtitles, the Adventure Log, the map's sensor settings, fast travel and its loading screen, a shrine and its elevator. A photo taken at 1.43 matches the 16:9 photo at scale 1.0 (before: only after a 1.24 vertical stretch).
  • On this base (e5620b1a), the game built with the NSP script (--platform mac --allow-other-metal: this Mac's Metal compiler is Xcode 27.1's 32023.921, the lock's 32023.922), with a save standing by an NPC in Kakariko Village: the title, the field, the NPC's dialog (the backing's copy centred on the box, v 0.8605 against 0.9587 before the second commit; the box as dark below the 720 edge as above it), the inventory and the map at 1.43, and the same route with DM_SCREEN_ASPECT unset, unchanged. No [RED] line from the change.
• Devices and OS: Apple M1, macOS 27.0.1; iPhone Duo (A20 Pro), iOS 27.1, where the title band and the dialog band were reported, on an older base.
• scripts/regress.py impact origin/main..HEAD: Breath of the Wild (its profile), Tears of the Kingdom and Pokémon Scarlet (through loader.c's module loading). regress.py check was not run: this Mac has no harness root or the routes' saves, and building Tears of the Kingdom on this base would have taken another hour. With DM_SCREEN_ASPECT unset, or a profile without screen_aspect on, the loader writes nothing new and every stub keeps the original path (they test the ratio at state +0x58 first).
• Not checked: shops in game (their layouts were checked against the rules only), a compendium registration photo, and this exact version on an iPhone. The taller picture renders about a quarter more pixels.

Docs

• The finding is in its game note (dm/games/01007EF00011E000/README.md); docs/env_switches.tsv lists the four switches; dm/tools/docs_patches.py classifies screen_aspect and docs/agents/game-patches.md was regenerated
• A chain tool changed (none)
• No game files, keys or data extracted from a game in the change or the attachments

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