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doc: Intuition bootcamp — comprehensive enrichment of all subsystem articles
Transformed 8 stub articles (720 lines total) into full bootcamp-grade references (5,100+ lines) with architecture diagrams, complete code examples, struct field references, pitfalls, and best practices. IDCMP (idcmp.md — 1,060 lines): - IntuiMessage field reference with types, sizes, value ranges - Use-case cookbook: double-click, rubber-band, multi-signal, BOOPSI - When to use IDCMP vs alternatives (decision flowchart) - 5 named antipatterns with WRONG/RIGHT code - Memory safety checklist and defensive event loop template - Cross-platform comparison table (Win32, X11, Cocoa, Qt) Input Events (input_events.md — 850 lines): - Event class routing and QoS analysis (priority-as-QoS hierarchy) - Intuition consumption table (what survives the handler chain) - lowlevel.library bypass for CD32/game input - Latency analysis with pipeline timing budget (68000 vs 68040) - Input strategy comparison (IDCMP vs handler vs direct hardware) - Game input patterns: direct HW polling, CIA keyboard, hybrid handler - Signal pattern for proper handler→application communication Windows (windows.md — 370 lines): - Window anatomy diagram, WA_ tag reference tables - Refresh modes comparison (Simple/Smart/SuperBitMap) - Window types: standard, backdrop, borderless, GimmeZeroZero - Coordinate system, border offsets, struct Window fields - Modification API (move, resize, title, busy pointer) Gadgets (gadgets.md — 403 lines): - Three-generation evolution (raw/GadTools/BOOPSI) - Complete GadTools lifecycle with setup, creation, events, cleanup - Runtime state updates (GadTools vs raw Intuition) - Raw struct Gadget: GFLG_*, GACT_*, GTYP_* flag tables - Proportional and string gadget internals BOOPSI (boopsi.md — 505 lines): - Class hierarchy Mermaid diagram - Method dispatch sequence diagram - ICA interconnection architecture (icclass, modelclass, ICTARGET_IDCMP) - Full custom gadget class tutorial (4 steps with complete code) - Built-in class reference table - C++/Qt analog comparison table Menus (menus.md — 378 lines): - Menu hierarchy diagram (Menu → Item → Sub-Item) - GadTools NewMenu workflow with field reference - Event handling with multi-select chain walking - Checkmark/mutual exclusion, sub-menus, dynamic modification - Keyboard shortcut system (single-char and NM_COMMANDSTRING) Requesters (requesters.md — 370 lines): - EasyRequest return value logic table - ASL file requester with multi-select and full tag reference - ASL font and screenmode requesters - Non-blocking BuildEasyRequest/SysReqHandler pattern - Requester state persistence IntuitionBase (intuition_base.md — 267 lines): - Library version table (OS 1.2 through 3.2.x) - Struct field reference with safety annotations - ViewLord architecture diagram - LockIBase vs Forbid/Permit guidance - Complete library function overview (5 categories) README index updated with enriched article descriptions.
This commit is contained in:
Ilia Sharin
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[← Home](../README.md) · [Intuition](README.md)
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# BOOPSI — Basic Object-Oriented Programming System
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# BOOPSI — Basic Object-Oriented Programming System for Intuition
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## Overview
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## What Is BOOPSI?
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BOOPSI is AmigaOS's class-based object system for Intuition gadgets and images. Objects receive messages via `DoMethod()` and support inheritance and notification.
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BOOPSI is AmigaOS's built-in object-oriented framework for creating reusable, interconnectable UI components. Introduced in OS 2.0 (1990), it predates Java, Qt's signal/slot system, and COM — yet implements many of the same patterns: **inheritance, encapsulation, message-based dispatch, and reactive property binding**.
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BOOPSI is the foundation on which all modern Amiga GUI frameworks are built:
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```mermaid
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graph TB
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BOOPSI["BOOPSI<br/>(rootclass)"] --> GADGET["gadgetclass"]
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BOOPSI --> IMAGE["imageclass"]
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BOOPSI --> IC["icclass / modelclass"]
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GADGET --> PROP["propgclass<br/>(sliders)"]
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GADGET --> STR["strgclass<br/>(strings)"]
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GADGET --> BUTTON["buttongclass"]
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GADGET --> FRBUT["frbuttongclass"]
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GADGET --> GROUP["groupgclass"]
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GADGET --> CUSTOM["Your Custom Class"]
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IMAGE --> FRAME["frameiclass"]
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IMAGE --> FILL["fillrectclass"]
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IMAGE --> SYSI["sysiclass<br/>(system images)"]
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IC --> MODEL["modelclass"]
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style BOOPSI fill:#e8f4fd,stroke:#2196f3,color:#333
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style CUSTOM fill:#fff3e0,stroke:#ff9800,color:#333
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```
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### Why BOOPSI Matters
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| Problem | Before BOOPSI | With BOOPSI |
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|---|---|---|
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| Custom gadgets | Rewrite rendering, hit-testing, state from scratch | Inherit from `gadgetclass` — get all behavior free |
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| Gadget communication | Application must manually shuttle values between gadgets | ICA interconnection — gadgets notify each other directly |
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| Consistent look | Every app draws gadgets differently | Inherit standard imagery and behavior |
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| Extensibility | Requires source code modification | Subclass and override only what you need |
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---
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## Core Methods
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## Core Concepts
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| Method | Description |
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|---|---|
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| `OM_NEW` | Create new object |
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| `OM_DISPOSE` | Destroy object |
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| `OM_SET` | Set attributes |
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| `OM_GET` | Get attributes |
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| `OM_UPDATE` | Attribute changed notification |
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| `OM_NOTIFY` | Send notification to targets |
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| `GM_RENDER` | Render the gadget |
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| `GM_GOACTIVE` | Gadget activated by user |
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| `GM_HANDLEINPUT` | Process input while active |
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| `GM_GOINACTIVE` | Gadget deactivated |
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### 1. Classes, Objects, and Methods
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---
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| Concept | Amiga BOOPSI | C++ Analog | Qt Analog |
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|---|---|---|---|
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| **Class** | `struct IClass` | `class` definition | `QObject` subclass |
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| **Object** | `Object *` (opaque) | Class instance | `QObject *` |
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| **Method** | `DoMethod(obj, MethodID, ...)` | `obj->method()` | `QMetaObject::invokeMethod()` |
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| **Attribute** | `SetAttrs(obj, TAG_ID, value)` | `obj->setX(val)` | `obj->setProperty("x", val)` |
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| **Superclass** | `DoSuperMethod(cl, obj, msg)` | Base class call | `QObject::event()` chain |
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| **Instance data** | `INST_DATA(cl, obj)` | `this->member` | `d_ptr` (Pimpl) |
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| **Interconnection** | `ICA_TARGET` + `ICA_MAP` | Observer pattern | `connect(signal, slot)` |
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## Built-in Classes
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### 2. The Dispatcher
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| Class | Description |
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|---|---|
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| `rootclass` | Base class for all BOOPSI objects |
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| `gadgetclass` | Base gadget class |
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| `imageclass` | Base image class |
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| `strgclass` | String entry gadget |
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| `buttongclass` | Button gadget |
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| `propgclass` | Proportional slider |
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| `groupgclass` | Group container |
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| `frbuttonclass` | Framed button |
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| `frameiclass` | Frame image |
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| `sysiclass` | System images (checkmark, etc.) |
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| `icclass` | Interconnection (maps attributes) |
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| `modelclass` | Model for MVC pattern |
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---
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## Creating and Using Objects
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Every class has a single **dispatcher function** — the equivalent of a virtual method table compressed into a switch statement:
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```c
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Object *button = NewObject(NULL, "frbuttonclass",
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GA_Left, 20,
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GA_Top, 40,
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GA_Width, 100,
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GA_Height, 20,
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GA_Text, "Click Me",
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GA_ID, 42,
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ULONG MyDispatcher(struct IClass *cl, Object *obj, Msg msg)
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{
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switch (msg->MethodID)
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{
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case OM_NEW: return MyNew(cl, obj, (struct opSet *)msg);
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case OM_DISPOSE: return MyDispose(cl, obj, msg);
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case OM_SET: return MySet(cl, obj, (struct opSet *)msg);
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case OM_GET: return MyGet(cl, obj, (struct opGet *)msg);
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case OM_UPDATE: return MySet(cl, obj, (struct opSet *)msg);
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default: return DoSuperMethodA(cl, obj, msg);
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}
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}
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```
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### 3. Method Dispatch Flow
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```mermaid
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sequenceDiagram
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participant App as Application
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participant Obj as Object
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participant Disp as Dispatcher
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participant Super as Superclass
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App->>Obj: DoMethod(obj, OM_SET, tags)
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Obj->>Disp: Dispatcher(cl, obj, msg)
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Disp->>Disp: Handle known attributes
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Disp->>Super: DoSuperMethodA(cl, obj, msg)
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Super-->>Disp: Return value
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Disp-->>App: Return value
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```
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---
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## Standard Methods
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### Object Lifecycle
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| Method | Message Struct | When Called | Your Job |
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|---|---|---|---|
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| `OM_NEW` | `struct opSet` | Object creation (`NewObject()`) | Allocate resources, parse initial tags, call super first |
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| `OM_DISPOSE` | `Msg` (base) | Object destruction (`DisposeObject()`) | Free your resources, then call super |
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### Attribute Access
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| Method | Message Struct | When Called | Your Job |
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|---|---|---|---|
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| `OM_SET` | `struct opSet` | `SetAttrs()` / `SetGadgetAttrs()` | Parse tag list, update internal state, notify if changed |
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| `OM_GET` | `struct opGet` | `GetAttr()` | Check `opg_AttrID`, store value in `*opg_Storage` |
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| `OM_UPDATE` | `struct opUpdate` | ICA notification from another object | Same as OM_SET, but check `opu_Flags` for interim updates |
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| `OM_NOTIFY` | `struct opUpdate` | Internal — trigger notifications to ICA targets | Called by your OM_SET handler when attributes change |
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### Gadget-Specific Methods
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| Method | When Called | Your Job |
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|---|---|---|
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| `GM_RENDER` | Intuition needs gadget redrawn | Draw the gadget using the provided `GadgetInfo` |
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| `GM_HITTEST` | Mouse click — is it inside your gadget? | Return `GMR_GADGETHIT` or 0 |
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| `GM_GOACTIVE` | Gadget becomes active (clicked) | Begin interaction; return `GMR_MEACTIVE` to stay active |
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| `GM_HANDLEINPUT` | Mouse/key events while active | Process input; return `GMR_MEACTIVE`, `GMR_NOREUSE`, or `GMR_REUSE` |
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| `GM_GOINACTIVE` | Gadget deactivated | Clean up interaction state |
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---
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## Creating Objects
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### Using Built-in Classes
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```c
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/* Create a proportional gadget (slider) */
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Object *slider = NewObject(NULL, "propgclass",
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GA_ID, 1,
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GA_Left, 20,
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GA_Top, 40,
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GA_Width, 200,
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GA_Height, 16,
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GA_RelVerify, TRUE,
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PGA_Freedom, FREEHORIZ,
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PGA_Total, 100,
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PGA_Top, 0,
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PGA_Visible, 10,
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TAG_DONE);
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AddGadget(win, (struct Gadget *)button, -1);
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RefreshGadgets((struct Gadget *)button, win, NULL);
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/* Add to window */
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AddGadget(win, (struct Gadget *)slider, -1);
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RefreshGList((struct Gadget *)slider, win, NULL, 1);
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/* Set attribute: */
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SetGadgetAttrs((struct Gadget *)button, win, NULL,
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GA_Disabled, TRUE,
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/* Read current position */
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LONG pos;
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GetAttr(PGA_Top, slider, (ULONG *)&pos);
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/* Update position */
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SetGadgetAttrs((struct Gadget *)slider, win, NULL,
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PGA_Top, 50,
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TAG_DONE);
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/* Get attribute: */
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ULONG value;
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GetAttr(GA_Disabled, button, &value);
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/* Destroy */
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RemoveGadget(win, (struct Gadget *)slider);
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DisposeObject(slider);
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```
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/* Cleanup: */
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RemoveGadget(win, (struct Gadget *)button);
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DisposeObject(button);
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### Using a Class Pointer
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```c
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/* When you have a Class * instead of a name */
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struct IClass *myClass = MakeMyClass();
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Object *obj = NewObject(myClass, NULL,
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MY_Attribute, value,
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TAG_DONE);
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```
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---
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## ICA — Interconnection Architecture
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The most powerful BOOPSI feature: **reactive data binding between objects** without application intervention.
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### Direct Connection (icclass)
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```mermaid
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graph LR
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SLIDER["Slider<br/>(propgclass)"] -->|"PGA_Top changes"| IC["icclass<br/>(mapper)"]
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IC -->|"Mapped attribute"| READOUT["Number Display<br/>(strgclass)"]
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style IC fill:#e8f4fd,stroke:#2196f3,color:#333
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```
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```c
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/* Map slider position to string gadget value */
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struct TagItem sliderToReadout[] = {
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{ PGA_Top, STRINGA_LongVal },
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{ TAG_DONE, 0 }
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};
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/* Create interconnection */
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SetAttrs(slider,
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ICA_TARGET, readout, /* Target object */
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ICA_MAP, sliderToReadout, /* Attribute mapping */
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TAG_DONE);
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/* Now when slider moves, readout updates automatically! */
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```
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### Broadcast (modelclass)
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For one-to-many notifications:
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```c
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/* Create a model (data source) */
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Object *model = NewObject(NULL, "modelclass",
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ICA_TARGET, ICTARGET_IDCMP, /* Also notify application */
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TAG_DONE);
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/* Add multiple views */
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DoMethod(model, OM_ADDMEMBER, slider);
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DoMethod(model, OM_ADDMEMBER, readout);
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DoMethod(model, OM_ADDMEMBER, gauge);
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/* Update the model — all views update automatically */
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SetAttrs(model, MY_VALUE, 42, TAG_DONE);
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```
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### ICA → IDCMP Bridge
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When `ICA_TARGET` is `ICTARGET_IDCMP`, attribute changes generate `IDCMP_IDCMPUPDATE` messages:
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```c
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SetAttrs(slider,
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ICA_TARGET, ICTARGET_IDCMP,
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TAG_DONE);
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/* In event loop: */
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case IDCMP_IDCMPUPDATE:
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{
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struct TagItem *tags = (struct TagItem *)msg->IAddress;
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LONG value = GetTagData(PGA_Top, 0, tags);
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UpdateApplication(value);
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break;
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}
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```
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---
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## Writing a Custom Class
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```c
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Class *myclass = MakeClass(NULL, "gadgetclass", NULL,
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sizeof(struct MyData), 0);
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myclass->cl_Dispatcher.h_Entry = (HOOKFUNC)myDispatcher;
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### Step 1: Define Instance Data
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ULONG myDispatcher(Class *cl, Object *o, Msg msg) {
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switch (msg->MethodID) {
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case OM_NEW: return myNew(cl, o, (struct opSet *)msg);
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case OM_DISPOSE: return myDispose(cl, o, msg);
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case GM_RENDER: return myRender(cl, o, (struct gpRender *)msg);
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default: return DoSuperMethodA(cl, o, msg);
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```c
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struct MyGadgetData {
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LONG value;
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LONG minVal;
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LONG maxVal;
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UWORD fgPen;
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UWORD bgPen;
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BOOL active;
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};
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```
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### Step 2: Implement the Dispatcher
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```c
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ULONG MyGadgetDispatcher(struct IClass *cl, Object *obj, Msg msg)
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{
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struct MyGadgetData *data;
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switch (msg->MethodID)
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{
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case OM_NEW:
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{
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/* Let superclass create the object first */
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Object *newObj = (Object *)DoSuperMethodA(cl, obj, msg);
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if (!newObj) return 0;
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data = INST_DATA(cl, newObj);
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data->value = 0;
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data->minVal = 0;
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data->maxVal = 100;
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data->fgPen = 1;
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data->bgPen = 0;
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data->active = FALSE;
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/* Parse initial tags */
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struct TagItem *tags = ((struct opSet *)msg)->ops_AttrList;
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struct TagItem *tag;
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while ((tag = NextTagItem(&tags)))
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{
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switch (tag->ti_Tag)
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{
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case MYGA_Value: data->value = tag->ti_Data; break;
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case MYGA_Min: data->minVal = tag->ti_Data; break;
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case MYGA_Max: data->maxVal = tag->ti_Data; break;
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}
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}
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return (ULONG)newObj;
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}
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case OM_SET:
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case OM_UPDATE:
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{
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data = INST_DATA(cl, obj);
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struct TagItem *tags = ((struct opSet *)msg)->ops_AttrList;
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struct TagItem *tag;
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BOOL refresh = FALSE;
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while ((tag = NextTagItem(&tags)))
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{
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switch (tag->ti_Tag)
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{
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case MYGA_Value:
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if (data->value != tag->ti_Data)
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{
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data->value = tag->ti_Data;
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refresh = TRUE;
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}
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break;
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}
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}
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/* Propagate to superclass */
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DoSuperMethodA(cl, obj, msg);
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/* Notify ICA targets of changes */
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if (refresh)
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{
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struct TagItem notify[] = {
|
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{ MYGA_Value, data->value },
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{ TAG_DONE, 0 }
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};
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DoSuperMethod(cl, obj, OM_NOTIFY, notify,
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((struct opSet *)msg)->ops_GInfo, 0);
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}
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return refresh;
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}
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case OM_GET:
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{
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data = INST_DATA(cl, obj);
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struct opGet *opg = (struct opGet *)msg;
|
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switch (opg->opg_AttrID)
|
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{
|
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case MYGA_Value:
|
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*opg->opg_Storage = data->value;
|
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return TRUE;
|
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default:
|
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return DoSuperMethodA(cl, obj, msg);
|
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}
|
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}
|
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|
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case GM_RENDER:
|
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{
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data = INST_DATA(cl, obj);
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struct gpRender *gpr = (struct gpRender *)msg;
|
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struct RastPort *rp = gpr->gpr_RPort;
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struct Gadget *g = (struct Gadget *)obj;
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|
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/* Draw the gadget */
|
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SetAPen(rp, data->bgPen);
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RectFill(rp, g->LeftEdge, g->TopEdge,
|
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g->LeftEdge + g->Width - 1,
|
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g->TopEdge + g->Height - 1);
|
||||
|
||||
/* Draw value bar */
|
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LONG barWidth = (data->value - data->minVal) *
|
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g->Width / (data->maxVal - data->minVal);
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SetAPen(rp, data->fgPen);
|
||||
RectFill(rp, g->LeftEdge, g->TopEdge,
|
||||
g->LeftEdge + barWidth - 1,
|
||||
g->TopEdge + g->Height - 1);
|
||||
|
||||
return TRUE;
|
||||
}
|
||||
|
||||
case GM_HITTEST:
|
||||
{
|
||||
/* Simple rectangular hit test — already handled by gadgetclass */
|
||||
return GMR_GADGETHIT;
|
||||
}
|
||||
|
||||
default:
|
||||
return DoSuperMethodA(cl, obj, msg);
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### Step 3: Register the Class
|
||||
|
||||
```c
|
||||
struct IClass *MyGadgetClass = NULL;
|
||||
|
||||
struct IClass *InitMyGadgetClass(void)
|
||||
{
|
||||
MyGadgetClass = MakeClass(
|
||||
NULL, /* Public name (NULL = private) */
|
||||
"gadgetclass", /* Superclass name */
|
||||
NULL, /* Superclass pointer (alt.) */
|
||||
sizeof(struct MyGadgetData), /* Instance data size */
|
||||
0 /* Flags */
|
||||
);
|
||||
|
||||
if (MyGadgetClass)
|
||||
MyGadgetClass->cl_Dispatcher.h_Entry = (HOOKFUNC)MyGadgetDispatcher;
|
||||
|
||||
return MyGadgetClass;
|
||||
}
|
||||
|
||||
/* For a public class (usable by other programs): */
|
||||
struct IClass *pubClass = MakeClass(
|
||||
"mygadget.class", /* Public name */
|
||||
"gadgetclass",
|
||||
NULL,
|
||||
sizeof(struct MyGadgetData),
|
||||
0
|
||||
);
|
||||
AddClass(pubClass); /* Register with Intuition */
|
||||
```
|
||||
|
||||
### Step 4: Use Your Class
|
||||
|
||||
```c
|
||||
struct IClass *cl = InitMyGadgetClass();
|
||||
|
||||
Object *gauge = NewObject(cl, NULL,
|
||||
GA_Left, 20,
|
||||
GA_Top, 60,
|
||||
GA_Width, 200,
|
||||
GA_Height, 20,
|
||||
MYGA_Value, 50,
|
||||
MYGA_Min, 0,
|
||||
MYGA_Max, 100,
|
||||
TAG_DONE);
|
||||
|
||||
/* Connect slider to gauge via ICA */
|
||||
SetAttrs(slider,
|
||||
ICA_TARGET, gauge,
|
||||
ICA_MAP, sliderToGauge,
|
||||
TAG_DONE);
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## Built-in Class Hierarchy
|
||||
|
||||
| Class | Superclass | Purpose |
|
||||
|---|---|---|
|
||||
| `rootclass` | — | Base of all BOOPSI objects |
|
||||
| `imageclass` | `rootclass` | Base for all images |
|
||||
| `frameiclass` | `imageclass` | Recessed/raised 3D frames |
|
||||
| `sysiclass` | `imageclass` | System images (arrows, checkmarks) |
|
||||
| `fillrectclass` | `imageclass` | Filled rectangles with patterns |
|
||||
| `gadgetclass` | `rootclass` | Base for all gadgets |
|
||||
| `propgclass` | `gadgetclass` | Proportional (slider) gadgets |
|
||||
| `strgclass` | `gadgetclass` | String input gadgets |
|
||||
| `buttongclass` | `gadgetclass` | Push buttons |
|
||||
| `frbuttongclass` | `gadgetclass` | Framed push buttons |
|
||||
| `groupgclass` | `gadgetclass` | Container for gadget groups |
|
||||
| `icclass` | `rootclass` | Interconnection (1-to-1 binding) |
|
||||
| `modelclass` | `icclass` | Interconnection (1-to-many broadcast) |
|
||||
|
||||
---
|
||||
|
||||
## Pitfalls
|
||||
|
||||
### 1. Forgetting DoSuperMethodA
|
||||
|
||||
If you handle `OM_NEW` without calling `DoSuperMethodA()` first, the object is never properly allocated. If you handle `OM_DISPOSE` without calling super last, the base class never frees its memory.
|
||||
|
||||
### 2. OM_SET Without OM_NOTIFY
|
||||
|
||||
If you update internal state in `OM_SET` but don't call `OM_NOTIFY`, ICA connections are silently broken — connected objects never update.
|
||||
|
||||
### 3. Wrong INST_DATA Timing
|
||||
|
||||
In `OM_NEW`, you must call `DoSuperMethodA()` **before** `INST_DATA()`. The superclass allocates the memory that `INST_DATA()` points to.
|
||||
|
||||
### 4. Modifying Gadget Attrs Without Window
|
||||
|
||||
`SetGadgetAttrs()` requires a window pointer to trigger a visual refresh. `SetAttrs()` alone updates internal state but doesn't redraw.
|
||||
|
||||
### 5. ICA Map Memory Management
|
||||
|
||||
The `ICA_MAP` tag list must persist for the lifetime of the connection. If you pass a stack-allocated array, it becomes garbage when the function returns.
|
||||
|
||||
---
|
||||
|
||||
## Best Practices
|
||||
|
||||
1. **Always call `DoSuperMethodA()`** for methods you partially handle — let the superclass do its job
|
||||
2. **Use `NextTagItem()`** to iterate tag lists — it handles `TAG_SKIP`, `TAG_MORE`, etc.
|
||||
3. **Send `OM_NOTIFY`** whenever a settable attribute changes — this drives ICA
|
||||
4. **Keep dispatch fast** — complex rendering should be deferred to `GM_RENDER`
|
||||
5. **Use `ICA_TARGET = ICTARGET_IDCMP`** when the application needs to know about changes
|
||||
6. **Allocate `ICA_MAP` arrays statically** or in instance data — not on the stack
|
||||
7. **Private classes** (NULL name) are simpler and sufficient for most applications
|
||||
8. **Use `modelclass`** for MVC patterns — it's the Amiga's built-in observer
|
||||
|
||||
---
|
||||
|
||||
## References
|
||||
|
||||
- NDK39: `intuition/classusr.h`, `intuition/classes.h`
|
||||
- ADCD 2.1: `NewObject`, `DisposeObject`, `SetAttrs`, `GetAttr`, `DoMethod`
|
||||
- NDK 3.9: `intuition/classes.h`, `intuition/classusr.h`, `intuition/gadgetclass.h`, `intuition/imageclass.h`, `intuition/icclass.h`
|
||||
- ADCD 2.1: `NewObject()`, `DisposeObject()`, `SetAttrs()`, `GetAttr()`, `DoMethod()`
|
||||
- AmigaOS Reference Manual (RKRM): Libraries, Chapter 8 — BOOPSI
|
||||
- See also: [Gadgets](gadgets.md), [MUI Framework](frameworks/mui/README.md)
|
||||
|
|
|
|||
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Add table
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Reference in a new issue