Mega UI

API reference

Every public type, member and field, on one page.

Namespace MegaUI.Api. Everything else in the assembly is internal and is not a contract — see Versioning.

MegaUiApi

Member	Type	What it does
`ModGuid`	const string	`"MegaUI"`. Use it in your `[BepInDependency]`.
`ApiVersion`	static readonly int	The contract version. Moves only on a breaking change.
`Register(guid, definition)`	AppHandle	Puts your app on the desktop. Never throws, never returns null.
`Unregister(guid)`	bool	Takes it off again. The apps below move up.
`IsRegistered(guid)`	bool	Whether that guid currently has an app.
`BuiltinIcons`	IEnumerable<string>	The names accepted by `UiIcon.Builtin`.

AppDefinition

Field	Type	Default	What it does
`Title`	string	the guid	Label under the icon and on the tab. Cut at 18 characters.
`Icon`	UiIcon	`monitor`	The desktop icon.
`SortOrder`	int	0	Position in the column, low first. Ties break by guid.
`OnOpened`	Action	null	After the window becomes visible.
`OnClosed`	Action	null	On minimize, close, or walking away.

AppHandle

Member	Type	What it does
`Ok`	bool	False when the registration was refused.
`Problem`	string	Why it was refused, or null.
`Build(action)`	AppHandle	Describes the screen. Returns itself, so it chains.
`Refresh()`	void	Rebuilds the screen because its shape changed.

Every member is safe to call on a refused handle, so the happy path needs no guard.

UiIcon

Member	What it does
`UiIcon.Builtin(name)`	One of the bundled icons. Unknown names fall back to `monitor`.
`UiIcon.FromPng(bytes)`	Your own PNG, as bytes. Square looks best.

IUiBuilder

What Build hands you. Things stack down the window in the order you add them.

Method	What it adds
`Header(string)`	A section title.
`Label(string)`	Plain text.
`Value(Func<string>)`	Text re-read on every open.
`Note(string)`	Small dim text explaining the control above it.
`Button(string, Action)`	A full-width button.
`Toggle(string, Func<bool>, Action<bool>)`	A checkbox.
`Stepper(string, int, int, Func<int>, Action<int>)`	A number with − and +. Clamped for you.
`Slider(string, float, float, Func<float>, Action<float>)`	A continuous value, with the reading beside it.
`Dropdown(string, string[], Func<int>, Action<int>)`	One of a short list. Opens above the window.
`TextField(string, Func<string>, Action<string>)`	Typing. Holds the keyboard while focused; sets on end of edit.
`Stats(params (string, Func<string>)[])`	A row of big numbers with captions.
`ProgressBar(string, Func<float>)`	A bar. The fraction is clamped for you.
`Image(string, byte[], float)`	Built-in icon or your PNG, full width.
`Tabs(string[], Func<int>, Action<int>)`	A row of tabs. You decide what each one shows.
`List(string[], Func<int>, Action<int>)`	A pickable list, with optional icons.
`Columns(params Action<IUiBuilder>[])`	Builders side by side, sharing the width.
`Separator()`	A horizontal line.
`Gap(float)`	Vertical space. 12 pixels by default.
`Row(Action<IUiRow>)`	A line laid out left to right.
`Card(Action<IUiBuilder>)`	A panel that sizes itself to its contents.
`Diagram(float, Action<IUiDiagram>, bool)`	Free positioning. `bleed` runs it edge to edge.
`Raw(float)`	A positioned rectangle of the right width. Yours.
`Area`	The visible area in pixels, for sizing something to the window.
`Font`	The game's TMP font, for anything you draw yourself.

Every colour is an optional parameter on the widget that uses it. See Look and feel.

IUiDiagram

What Diagram and Region hand you. Origin at the top-left, y downwards.

Method	What it draws
`Node(float, float, ...)`	A disc with a ring, an icon and a level. Every state colour can be overridden.
`Link(float, float, float, float, ...)`	A connector. Straight lines join without gaps.
`Text(float, float, string, ...)`	Free text, with `UiAlign` and optional shrink-to-fit.
`Box(float, float, float, float, ...)`	A filled rectangle, optionally rounded.
`Button(float, float, float, float, ...)`	A button at an exact spot. Its label shrinks to fit by default.
`Image(float, float, float, float, ...)`	Built-in icon or your PNG.
`Region(float, float, float, float, ..., pan)`	A clipped sub-surface, optionally draggable and zoomable.
`Raw(float, float, float, float)`	A positioned rectangle. Yours.
`Size` / `Theme`	The surface size, and the colours in force.

IUiRow

Method	What it adds
`Label(string)`	Text, sized to what it contains.
`Value(Func<string>)`	Text re-read on every open, resized as it changes.
`Button(string, Action)`	A button sized to its text.
`Icon(string)`	A built-in icon at row height.
`Spacer()`	Everything after it anchors to the right edge.
`Gap(float)`	Horizontal space. 8 pixels by default.

Things that are true of all of it

Nothing throws at you. A refusal is a return value, never an exception.
Your callbacks are wrapped. A throw inside one is logged with your guid and swallowed.
You never pass a coordinate — unless you asked for a diagram, where placing things is the whole point.
Every colour is optional. Nothing is forced; the theme is the default.
Every Func is read again on every open.