[danbopes]

Addresses the report that the signal window does not fit on screen in pY.

The problem

The grid was a fixed 8-column table with no scroll pane and no height cap, so the window grew one row per 8 signals without bound. Measured on a graphical 2.1.7 host at 3600x2025 / 1.5 UI scale:

signals	before	after
8	8 cols, 1 row	8 cols, 1 row (unchanged)
60	8 cols, 8 rows	10 cols, 6 rows
400	8 cols, 50 rows	24 cols, 17 rows
800	8 cols, 100 rows, pinned to y=0	24 cols, 20 visible + scroll
1502	8 cols, 188 rows	24 cols, 20 visible + scroll

At 800 signals the old window sat at y=0 and ran off the bottom with roughly a third of the rows reachable and no way to get at the rest.

Approach

Widening alone does not solve it. 800 signals still needs 24 columns to fit at 1080p, and a window that wide is absurd for a reader showing three signals. So the grid sizes itself, with no settings to configure:

• Table lives in a scroll-pane capped at 60% of screen height, rounded down to whole rows so none is cut in half.
• Column count derives from the signal count, clamped to what the screen allows. Small readers stay as compact as today; large ones widen to the cap and then scroll.

Rode along

Three things that only bite at this scale:

• update_signal_display cleared and refilled the whole table each update, which would reset scroll position twice a second and rebuild hundreds of elements. Buttons are now updated in place, surplus destroyed.
• Section 2 is rebuilt from a hash table each update, so order drifted between refreshes. Entries now sort into prototype order, keyed by type/name/quality so the order is total and identical on every client.
• The per-button prototype lookup had no nil guard, so opening a reader whose stored output named an item from a removed mod raised.

Also fixed force_auto_center running before the grid was populated, which centred the empty window and left it hanging off the bottom as rows arrived.

Net diff is three files: gui.lua, gui-styles.lua (drops the dead cybersyn_content_reader_signal_display style that hardcoded the 280x300 geometry this replaces), and changelog.txt.

Verification

Suite is 9/9 (./factorio-test.py cybersyn-content-reader). Screenshots taken against a live graphical host at each of the sizes in the table, including scrolled-to-bottom at 800.

Not exercised end-to-end: scroll position surviving a live Update_Combinator cycle. That needs a tracked reader, whose section 2 gets overwritten from real Cybersyn state each tick, which would wipe the synthetic signals. The change is structural (no more clear()), but I did not watch it happen in game.

Versioning

Stays on the pending 1.1.1. Only 1.1.0 is tagged on the remote, so the Version: 1.1.1 / Date: ???? block is fmtk's post-release stub from shipping 1.1.0 and was never published; these entries belong in it.

🤖 Generated with Claude Code

https://claude.ai/code/session_01A47dkZVVahTZsepP8LnbLM