wlgol/openspec/changes/archive/2026-11-08-arena-size/specs/arena-sizing/spec.md

Spec Delta

Purpose

Defines how the arena default size is derived from the output and how resizing affects the grid.

ADDED Requirements

Requirement: Default arena is about 80% of output

The system SHALL compute the default logical window size as 80% of the output mode dimensions divided by the active scale.

Scenario: Output available

• WHEN output mode and scale are known at startup
• THEN the default logical window size is approximately 80% of the output

Requirement: Fallback when output unknown

The system SHALL use a fallback default size when output info is unavailable.

Scenario: No output info

• WHEN output mode is not reported
• THEN a fallback logical size is used

Requirement: Cell size remains 8 logical pixels

The system SHALL keep an 8 logical pixel cell size.

Scenario: Grid dimensions

• WHEN the logical window size is known
• THEN grid columns and rows are logical size divided by 8

Requirement: Resizable window

The system SHALL allow the window to be resized by the user.

Scenario: Resize

• WHEN the user resizes the window
• THEN the grid dimensions update accordingly

Requirement: Grid preserved on resize

The system SHALL preserve overlapping cells when the grid dimensions change.

Scenario: Enlarge

• WHEN the window grows
• THEN existing cells within the old bounds remain