docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections

Comprehensive technical documentation covering:
- Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives
- Boot sequence: cold boot through startup-sequence
- Binary format: HUNK executable spec, relocation, debug info
- Linking & ABI: .fd files, LVO tables, register calling conventions
- Exec kernel: tasks, interrupts, memory, signals, semaphores
- AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting
- Graphics: planar bitmaps, Copper programming, HAM/EHB modes
- Intuition: screens, windows, IDCMP, BOOPSI
- Devices: trackdisk, SCSI, serial, timer, audio, keyboard
- Libraries: utility, expansion, IFFParse, locale, ARexx
- Networking: bsdsocket API, SANA-II, TCP/IP stack comparison
- Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging
- Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies
- CPU & MMU: 68040/060 emulation libs, PMMU, cache management
- Driver development: SANA-II, Picasso96/RTG, AHI audio

All files include breadcrumb navigation. No local paths or proprietary content.

09_intuition/gadgets.md

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+[← Home](../README.md) · [Intuition](README.md)
+
+# Gadgets — GadTools and BOOPSI
+
+## Overview
+
+Intuition gadgets are the UI controls: buttons, string fields, sliders, checkboxes, listviews, etc. OS 2.0+ provides **GadTools** (high-level toolkit) and **BOOPSI** (object-oriented framework).
+
+---
+
+## GadTools Gadget Types
+
+| Kind | Constant | Description |
+|---|---|---|
+| Button | `BUTTON_KIND` | Simple push button |
+| Checkbox | `CHECKBOX_KIND` | Toggle on/off |
+| Integer | `INTEGER_KIND` | Numeric entry field |
+| Listview | `LISTVIEW_KIND` | Scrollable list |
+| MX | `MX_KIND` | Mutually exclusive (radio buttons) |
+| Number | `NUMBER_KIND` | Read-only number display |
+| Cycle | `CYCLE_KIND` | Pop-up cycle selector |
+| Palette | `PALETTE_KIND` | Colour picker |
+| Scroller | `SCROLLER_KIND` | Scroll bar |
+| Slider | `SLIDER_KIND` | Value slider |
+| String | `STRING_KIND` | Text entry field |
+| Text | `TEXT_KIND` | Read-only text display |
+
+---
+
+## Creating a GadTools Layout
+
+```c
+struct Screen *scr = LockPubScreen(NULL);
+APTR vi = GetVisualInfo(scr, TAG_DONE);
+struct Gadget *glist = NULL;
+struct NewGadget ng;
+struct Gadget *gad = CreateContext(&glist);
+
+ng.ng_LeftEdge   = 20;
+ng.ng_TopEdge    = 30;
+ng.ng_Width      = 100;
+ng.ng_Height     = 14;
+ng.ng_GadgetText = "OK";
+ng.ng_GadgetID   = 1;
+ng.ng_VisualInfo = vi;
+ng.ng_Flags      = 0;
+ng.ng_TextAttr   = NULL;
+
+gad = CreateGadget(BUTTON_KIND, gad, &ng, TAG_DONE);
+
+ng.ng_TopEdge += 20;
+ng.ng_GadgetText = "Cancel";
+ng.ng_GadgetID   = 2;
+gad = CreateGadget(BUTTON_KIND, gad, &ng, TAG_DONE);
+
+/* Open window with gadgets: */
+struct Window *win = OpenWindowTags(NULL,
+    WA_Gadgets, glist,
+    WA_IDCMP,   IDCMP_GADGETUP | IDCMP_CLOSEWINDOW | BUTTONIDCMP,
+    /* ... */
+    TAG_DONE);
+
+/* Event loop: */
+/* on IDCMP_GADGETUP: */
+/*   struct Gadget *gad = (struct Gadget *)imsg->IAddress; */
+/*   switch (gad->GadgetID) { case 1: ... case 2: ... } */
+
+/* Cleanup: */
+CloseWindow(win);
+FreeGadgets(glist);
+FreeVisualInfo(vi);
+UnlockPubScreen(NULL, scr);
+```
+
+---
+
+## BOOPSI (Basic Object-Oriented Programming System for Intuition)
+
+BOOPSI provides class-based gadgets with message dispatch:
+
+```c
+/* Create a BOOPSI string gadget: */
+Object *strObj = NewObject(NULL, "strgclass",
+    GA_Left,     20,
+    GA_Top,      50,
+    GA_Width,    200,
+    GA_Height,   14,
+    GA_ID,       3,
+    STRINGA_Buffer, myBuffer,
+    STRINGA_MaxChars, 64,
+    TAG_DONE);
+
+/* Add to window: */
+AddGadget(win, (struct Gadget *)strObj, -1);
+RefreshGadgets((struct Gadget *)strObj, win, NULL);
+
+/* Cleanup: */
+RemoveGadget(win, (struct Gadget *)strObj);
+DisposeObject(strObj);
+```
+
+---
+
+## References
+
+- NDK39: `libraries/gadtools.h`, `intuition/classusr.h`
+- ADCD 2.1: `CreateGadget`, `CreateContext`, `GetVisualInfo`