backend-infra-engineer: Post v0.3.9-hotfix7 snapshot (build cleanup)

docs/internal/agents/archive/plans-2025-11/hex_editor_enhancements.md

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+# Plan: Hex Editor Enhancements (Inspired by ImHex)
+
+**Status:** Active  
+**Owner (Agent ID):** imgui-frontend-engineer  
+**Last Updated:** 2025-11-25  
+**Next Review:** 2025-12-02  
+**Coordination Board Entry:** link when claimed
+
+This document outlines the roadmap for enhancing the `yaze` Memory/Hex Editor to provide robust analysis tools similar to ImHex.
+
+## Phase 1: Data Inspector (High Priority)
+
+**Goal:** Provide immediate context for the selected byte(s) in the Hex Editor without mental math.
+
+**Implementation Steps:**
+1.  **Create `DataInspector` Component:**
+    *   A standalone ImGui widget (`src/app/editor/code/data_inspector.h/cc`).
+    *   Accepts a `const uint8_t* data_ptr` and `size_t max_len`.
+2.  **Standard Types:**
+    *   Decode and display Little Endian values:
+        *   `int8_t` / `uint8_t`
+        *   `int16_t` / `uint16_t`
+        *   `int24_t` / `uint24_t` (Common SNES pointers)
+        *   `int32_t` / `uint32_t`
+    *   Display Binary representation (`00001111`).
+3.  **SNES-Specific Types (The "Yaze" Value):**
+    *   **SNES LoROM Address:** Convert the physical offset to `$BB:AAAA` format.
+    *   **RGB555 Color:** Interpret 2 bytes as `0bbbbbgggggrrrrr`. Show a colored rectangle preview.
+    *   **Tile Attribute:** Interpret byte as `vhopppcc` (Vertical/Horizontal flip, Priority, Palette, Tile High bit).
+4.  **Integration:**
+    *   Modify `MemoryEditorWithDiffChecker` to instantiate and render `DataInspector` in a sidebar or child window next to the main hex grid.
+    *   Hook into the hex editor's "Selection Changed" event (or poll selection state) to update the Inspector.
+
+## Phase 2: Entropy Navigation (Navigation)
+
+**Goal:** Visualize the ROM's structure to quickly find free space, graphics, or code.
+
+**Implementation Steps:**
+1.  **Entropy Calculator:**
+    *   Create a utility to calculate Shannon entropy for blocks of data (e.g., 256-byte chunks).
+    *   Run this calculation in a background thread when a ROM is loaded to generate an `EntropyMap`.
+2.  **Minimap Widget:**
+    *   Render a thin vertical bar next to the hex scrollbar.
+    *   Map the file offset to vertical pixels.
+    *   **Color Coding:**
+        *   **Black:** Zeroes (`0x00` fill).
+        *   **Dark Grey:** `0xFF` fill (common flash erase value).
+        *   **Blue:** Low entropy (Text, Tables).
+        *   **Red:** High entropy (Compressed Graphics, Code).
+3.  **Interaction:**
+    *   Clicking the minimap jumps the Hex Editor to that offset.
+
+## Phase 3: Structure Templates (Advanced Analysis)
+
+**Goal:** Define and visualize complex data structures on top of the raw hex.
+
+**Implementation Steps:**
+1.  **Template Definition System:**
+    *   Define a C++-based schema builder (e.g., `StructBuilder("Header").AddString("Title", 21).AddByte("MapMode")...`).
+2.  **Visualizer:**
+    *   Render these structures as a tree view (ImGui TreeNodes).
+    *   When a tree node is hovered, highlight the corresponding bytes in the Hex Editor grid.
+3.  **Standard Templates:**
+    *   Implement templates for known ALTTP structures: `SNES Header`, `Dungeon Header`, `Sprite Properties`.
+
+## Phase 4: Disassembly Integration
+
+**Goal:** Seamless transition between data viewing and code analysis.
+
+**Implementation Steps:**
+1.  **Context Menu:** Add "Disassemble Here" to the Hex Editor right-click menu.
+2.  **Disassembly View:**
+    *   Invoke the `disassembler` (already present in `app/emu/debug`) on the selected range.
+    *   Display the output in a popup or switch to the Assembly Editor.
+
+---
+
+## Initial Work Item: Data Inspector
+
+We will begin with Phase 1. This requires creating the `DataInspector` class and hooking it into `MemoryEditorWithDiffChecker`.