Windowing

Windowing

Each GuiBase subclass renders as an independent window that can be positioned, dragged, and resized. Multiple windows can be open simultaneously.

WindowConfig

Override CreateWindowConfig() to configure window behavior:

protected override WindowConfig CreateWindowConfig() => new()
{
    Size = new Vector2(800, 600),     // fixed size; null = shrink-wrap to content
    Position = new Vector2(100, 50),  // initial position; null = centered on screen
    MinSize = new Vector2(200, 100),  // resize clamp
    MaxSize = new Vector2(1600, 900), // resize clamp
    Draggable = true,                 // drag by title bar / top handle zone
    Resizable = true,                 // resize by edges and corners
    DragHandleHeight = 24f,           // height of the drag zone at the top
    ResizeHandleSize = 8f,            // edge grip width for resize detection
};

Properties

Property	Type	Default	Description
Position	Vector2?	null	Initial position in logical pixels. null = centered
Size	Vector2?	null	Fixed window size. null = shrink-wrap to content
MinSize	Vector2	(100, 50)	Minimum size for resize clamping
MaxSize	Vector2	(inf, inf)	Maximum size for resize clamping
Draggable	bool	true	Enable drag by the top handle zone
Resizable	bool	true	Enable edge/corner resize
DragHandleHeight	float	24	Height of the drag handle at the top
ResizeHandleSize	float	8	Width of the edge resize grip
IsShrinkWrap	bool	(computed)	true when Size == null

Fixed size vs shrink-wrap

• Fixed size (Size = new Vector2(w, h)): The root widget receives Tight(w, h) constraints. Content fills the window.
• Shrink-wrap (Size = null): The root widget receives Loose(screenW, screenH) constraints. The window sizes to its content.

Drag and Resize

When Draggable is true, clicking and dragging within the top DragHandleHeight pixels moves the window.

When Resizable is true, hovering over the window edges (within ResizeHandleSize pixels) shows resize cursors and allows dragging to resize. Corner regions resize on both axes simultaneously.

Resize cursors

The Library automatically sets the OS cursor when hovering resize zones:

Zone	Cursor
Left / Right edge	ResizeEW (horizontal arrows)
Top / Bottom edge	ResizeNS (vertical arrows)
Top-left / Bottom-right corner	ResizeNWSE (diagonal)
Top-right / Bottom-left corner	ResizeNESW (diagonal)

Resize throttle

Resizing defers relayout by a short delay (50ms) to avoid FPS drops during active resize. The visual window size updates immediately (for clipping), but the widget tree relayout is batched. On mouse-up, the final layout is committed immediately.

ResizeEdge flags

[Flags]
public enum ResizeEdge
{
    None   = 0,
    Left   = 1,
    Right  = 2,
    Top    = 4,
    Bottom = 8,
}

Corner detection uses flag composition: Left | Top = top-left corner.

Multi-Window Support

GuiModSystem tracks all open windows:

// All open windows:
IReadOnlyList<GuiBase> windows = modSystem.OpenWindows;

// Currently active (focused) window:
GuiBase? active = modSystem.ActiveWindow;

Each GuiBase calls SkiaRenderer.Begin() / End() independently in its own OnRenderGUI, so windows are fully isolated rendering passes.

WindowTitleBar

A title bar widget with title text, minimize (collapse), and close buttons. Add it as the first child in a Column:

protected override Widget Build() =>
    new Column(children:
    [
        new WindowTitleBar(
            title: "My Window",
            onClose: () => TryClose(),
            onMinimizeChanged: minimized => { /* show/hide content */ },
        ),
        new Expanded(child: myContent),
    ]);

Parameters

Parameter	Type	Default	Description
title	string	""	Title text
height	float	28	Title bar height
onClose	Action?	null	Close button callback
onMinimizeChanged	Action<bool>?	null	Minimize toggle callback
backgroundColor	Vector4?	dark gray	Title bar background
textColor	Vector4?	light gray	Title and button text color
buttonHoverColor	Vector4?	medium gray	Minimize button hover color
closeHoverColor	Vector4?	red	Close button hover color
fontSize	float	14	Title font size
showMinimize	bool	true	Show minimize button
showClose	bool	true	Show close button

WindowFrame

A convenience widget that wraps WindowTitleBar + content and handles minimize state internally:

protected override Widget Build() =>
    new WindowFrame(
        title: "My Window",
        onClose: () => TryClose(),
        child: myContent,
    );

When minimized, only the title bar is visible; the child is removed from the tree.

Parameters

Parameter	Type	Default	Description
title	string	""	Title text
child	Widget?	null	Window content
onClose	Action?	null	Close button callback
titleBarHeight	float	28	Title bar height
backgroundColor	Vector4?	dark gray	Title bar background
textColor	Vector4?	light gray	Text color
fontSize	float	14	Title font size
showMinimize	bool	true	Show minimize button
showClose	bool	true	Show close button

Complete Example

public class MyToolWindow : GuiBase
{
    public MyToolWindow(ICoreClientAPI capi) : base(capi) { }

    protected override WindowConfig CreateWindowConfig() => new()
    {
        Size = new Vector2(400, 300),
        Draggable = true,
        Resizable = true,
        MinSize = new Vector2(200, 100),
    };

    protected override Widget Build() =>
        new WindowFrame(
            title: "Tool Window",
            onClose: () => TryClose(),
            child: new Padding(
                EdgeInsets.All(12),
                child: new Text("Window content here")
            )
        );
}

Dialog Type

To switch between interactive dialog and HUD element, override DialogType on your GuiBase subclass:

public override EnumDialogType DialogType => EnumDialogType.HUD;