# DVX Widget Modules

Individual widget type implementations for the DVX GUI, each built
as a separate `.wgt` DXE module.  The loader scans the `WIDGETS/`
directory recursively at startup and loads every `.wgt` file it
finds, calling `wgtRegister()` on each to fill the widget class
table.

Drop a new `.wgt` file in the directory and it is automatically
available -- no loader or core library changes needed.


## How Widget DXEs Work

Each `.wgt` module contains:

1. The widget implementation (paint, layout, mouse/key handlers)
2. A `static const WidgetClassT` vtable definition
3. A `wgtRegister()` function that writes the vtable pointer into
   `widgetClassTable[]` at the widget's enum slot
4. The public API functions (e.g. `wgtTreeView()`, `wgtTreeViewGetSelected()`)

At load time, the module resolves its dependencies against:
- The loader's `dlregsym` table (platform functions, libc)
- `libtasks.lib` exports (stb_ds dynamic arrays)
- `libdvx.lib` exports (widget infrastructure: `widgetAlloc`,
  `widgetClassTable`, `widgetScrollbarThumb`, shared state, etc.)
- Other widget modules loaded earlier (via `RTLD_GLOBAL`)


## Widget Catalog

| Module | Widget Types | Description |
|--------|-------------|-------------|
| `box.wgt` | VBox, HBox, Frame | Containers: vertical/horizontal box layout, titled frame |
| `button.wgt` | Button | Push button with text and keyboard accelerator |
| `canvas.wgt` | Canvas | Freeform drawing surface with mouse callbacks |
| `checkbox.wgt` | Checkbox | Toggle checkbox with label |
| `combobox.wgt` | ComboBox | Editable text input with dropdown list |
| `dropdown.wgt` | Dropdown | Non-editable dropdown selector |
| `image.wgt` | Image | Static image display (BMP/PNG/JPEG/GIF) |
| `imgbtn.wgt` | ImageButton | Button with icon image |
| `label.wgt` | Label | Static text display with optional accelerator |
| `listbox.wgt` | ListBox | Scrollable string list with single/multi select |
| `listview.wgt` | ListView | Multi-column list with headers, sorting, column resize |
| `progress.wgt` | ProgressBar | Horizontal or vertical progress indicator |
| `radio.wgt` | RadioGroup, Radio | Mutually exclusive option buttons |
| `scrlpane.wgt` | ScrollPane | Scrollable viewport for oversized content |
| `separatr.wgt` | Separator | Horizontal or vertical divider line |
| `slider.wgt` | Slider | Horizontal value slider with thumb |
| `spacer.wgt` | Spacer | Invisible layout spacer |
| `spinner.wgt` | Spinner | Numeric input with up/down buttons |
| `splitter.wgt` | Splitter | Resizable two-pane divider |
| `statbar.wgt` | StatusBar | Horizontal bar at window bottom |
| `tabctrl.wgt` | TabControl, TabPage | Tabbed page container |
| `terminal.wgt` | AnsiTerm | VT100 terminal emulator with scrollback |
| `textinpt.wgt` | TextInput, TextArea | Single-line and multi-line text editing |
| `timer.wgt` | Timer | Periodic callback (no visual) |
| `toolbar.wgt` | Toolbar | Horizontal button/widget bar |
| `treeview.wgt` | TreeView, TreeItem | Hierarchical tree with expand/collapse |

26 modules implementing 32 widget types (some modules register
multiple related types).


## Writing a New Widget

1. Create `widgets/myWidget.c`
2. Include `"widgetInternal.h"` for infrastructure access
3. Implement paint, calcMinSize, and event handlers as needed
4. Define a `static const WidgetClassT` with your vtable
5. Add a `wgtRegister()` function:
   ```c
   void wgtRegister(void) {
       widgetClassTable[MyWidgetTypeE] = &sClassMyWidget;
   }
   ```
6. Add the new enum value to `WidgetTypeE` in `core/dvxWidget.h`
   (or use `wgtRegisterClass()` for a fully dynamic type ID)
7. Add public API functions (e.g. `wgtMyWidget()`) that call
   `widgetAlloc(parent, MyWidgetTypeE)`
8. Add a build rule in `widgets/Makefile`
9. Build -- the loader discovers and loads it automatically


## Building

```
make        # compiles all widget .c files, creates .wgt modules in ../bin/widgets/
make clean
```

Each `.wgt` is created with `dxe3gen -E _wgt -U`, which exports all
symbols starting with `wgt` (public API + `wgtRegister`) and allows
unresolved symbols (resolved at load time from other modules).