Gui

Immediate-mode GUI backed by Nuklear via a Vulkan backend. Call all GUI methods each frame from update(dt). All methods are static.

Windows

Gui.beginWindow(title, x, y, w, h)

Returns: Bool — true if the window is visible. If false, skip content but still call endWindow().

Parameters: title (String), x/y/w/h (Num) — Position and size in pixels.

if (Gui.beginWindow("Settings", 10, 10, 300, 200)) {
    Gui.layoutRowDynamic(22, 1)
    Gui.label("Volume: %(volume)")
    Gui.endWindow()
}

Gui.beginWindowEx(name, title, x, y, w, h, flags)

Extended window with a separate internal name (used by window-management functions) and flags (Num) for Nuklear NK_WINDOW_* flags.

Gui.endWindow()

End the current window. Must be called once per beginWindow/beginWindowEx.

Window management

Method	Description
windowGetBounds()	Returns [x, y, w, h] of the current window
windowGetContentRegion()	Returns [x, y, w, h] of the usable content area
windowGetPosition()	Returns [x, y]
windowGetSize()	Returns [w, h]
windowGetScroll()	Returns [xOffset, yOffset]
windowSetScroll(x, y)	Set scroll position
windowSetFocus(name)	Focus a named window
windowSetBounds(name, x, y, w, h)	Reposition and resize a named window
windowSetPosition(name, x, y)	Move a named window
windowCollapse(name, state)	Collapse (1) or expand (0)
windowShow(name, state)	Show (1) or hide (0)
windowClose(name)	Close a named window
isWindowHovered()	Bool — mouse is over the current window
isWindowFocused()	Bool — current window has keyboard focus
isWindowCollapsed(name)	Bool
isWindowClosed(name)	Bool
isAnyWindowHovered()	Bool — mouse is over any GUI window

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Layout

Gui.layoutRowDynamic(height, cols)

Divide the row equally into cols dynamic columns at height pixels tall.

Gui.layoutRowDynamic(28, 4)
if (Gui.buttonLabel("7")) _calc.digit(7)
if (Gui.buttonLabel("8")) _calc.digit(8)

Gui.layoutRowStatic(height, itemWidth, cols)

Fixed-width columns: each column is itemWidth pixels wide.

Gui.layoutRowBegin(format, height, cols) / Gui.layoutRowPush(value) / Gui.layoutRowEnd()

Manual column layout. format is 0 (static widths) or 1 (relative fractions). Push each column width/fraction with layoutRowPush then call layoutRowEnd.

Gui.layoutRowBegin(1, 30, 2)   // ratio mode, 2 cols
Gui.layoutRowPush(0.3)         // 30% wide
Gui.label("Name:")
Gui.layoutRowPush(0.7)         // 70% wide
_name = Gui.editString(_name, 64)
Gui.layoutRowEnd()

Row template

layoutRowTemplateBegin(height) / layoutRowTemplatePushDynamic() / layoutRowTemplatePushVariable(minWidth) / layoutRowTemplatePushStatic(width) / layoutRowTemplateEnd() — Define column types in a template then repeat it.

Space layout

layoutSpaceBegin(format, height, count) / layoutSpacePush(x, y, w, h) / layoutSpaceEnd() — Place each widget at an explicit rectangle within the layout space.

Other layout helpers

Method	Description
layoutSetMinRowHeight(height)	Set minimum row height
layoutResetMinRowHeight()	Reset to default
layoutWidgetBounds()	Returns [x, y, w, h] of next widget slot
spacing(cols)	Skip cols layout cells

---

Separator

Gui.separator(r, g, b, a, rounded)

Draw a colored horizontal separator line. Colors are 0–255. rounded (Bool) — true for rounded ends, false for sharp.

Gui.separator(128, 128, 128, 60, true)

---

Labels

Method	Description
All color parameters in label methods are 0–255 integers.

Method	Description
label(text)	Non-editable label (left-aligned)
labelColored(text, r, g, b, a)	Colored label (colors 0–255)
labelWrap(text)	Word-wrapping label
labelColoredWrap(text, r, g, b, a)	Colored, wrapping label (colors 0–255)
labelAligned(text, align)	Aligned label: 0x11 = left, 0x12 = centered, 0x14 = right

Gui.labelColored("ERROR: file not found", 255, 80, 80, 255)

---

Buttons

Method	Returns	Description
buttonLabel(text)	Bool	Standard text button
buttonColor(r, g, b, a)	Bool	Solid color button (colors 0–255)
buttonSymbol(symbol)	Bool	Icon-only button (Nuklear symbol constant)
buttonSymbolLabel(symbol, text, align)	Bool	Icon + label
buttonSetBehavior(behavior)	—	0 = default (click), 1 = repeater (held fires every frame)

if (Gui.buttonLabel("Save")) saveGame()
if (Gui.buttonLabel("Quit")) quit()

---

Checkbox & radio

Gui.checkbox(label, active)

Returns: Bool — New active state (toggle when clicked).

_fullscreen = Gui.checkbox("Fullscreen", _fullscreen)
if (_fullscreen != _prevFullscreen) {
    Window.setFullscreen(_fullscreen)
}

Gui.radio(label, active)

Returns: Bool — true if this radio was just selected.

---

Selectable

Gui.selectableLabel(text, align, selected)

Returns: Bool — New selected state.

---

Sliders

Gui.sliderFloat(min, value, max, step)

Returns: Num — New value after user interaction.

_volume = Gui.sliderFloat(0, _volume, 1, 0.01)
Audio.setVolume(_volume)

Gui.sliderInt(min, value, max, step)

Returns: Num — New integer value.

---

Knobs

Gui.knobFloat(min, value, max, step, zeroDir, deadZone)

Returns: Num — New value. zeroDir sets where “zero” appears on the knob dial (0 = up, 1 = right, 2 = down, 3 = left). deadZone is a small radian threshold around the zero to reduce jitter.

Gui.knobInt(min, value, max, step, zeroDir, deadZone)

Returns: Num — New integer value.

---

Progress

Gui.progress(current, max, modifiable)

Returns: Num — Updated value (unchanged unless modifiable is true). Displays a horizontal progress bar.

_progress = Gui.progress(_progress, 100, true)

---

Property widgets

Gui.propertyFloat(name, min, value, max, step, incPerPixel)

Returns: Num — New value. Labeled numeric property with click-drag editing.

Gui.propertyInt(name, min, value, max, step, incPerPixel)

Returns: Num — New integer value.

---

Edit / input

Gui.editString(currentText, maxLen)

Returns: String — Current (possibly edited) text. Pass the returned value back each frame.

_widthStr = Gui.editString(_widthStr, 8)

Gui.lastEditCommitted()

Returns: Bool — true if the last edit field was submitted (Enter or focus lost).

Gui.editStringFiltered(text, maxLen, filter)

Returns: String — Text with a custom filter applied. filter is a string of allowed characters.

Gui.editFocus()

Give keyboard focus to the next edit widget.

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Color picker

Gui.colorPicker(r, g, b, a, format)

Returns: List — [r, g, b, a] (0–255). format is 0 for RGB, 1 for RGBA, 2 for HSV. Pass the returned values back as inputs next frame.

var result = Gui.colorPicker(_r, _g, _b, _a, 1)
_r = result[0]
_g = result[1]
_b = result[2]
_a = result[3]

---

Combo / dropdown

if (Gui.comboBeginLabel(_items[_selected], 150, 200)) {
    Gui.layoutRowDynamic(20, 1)
    for (item in _items) {
        if (Gui.comboItemLabel(item, 0)) _selected = _items.indexOf(item)
    }
    Gui.comboEnd()
}

Method	Returns	Description
comboBeginLabel(label, w, h)	Bool	Open a combo with a text label
comboBeginColor(r, g, b, a, w, h)	Bool	Open a combo with a color swatch (colors 0–255)
comboBeginSymbol(symbol, w, h)	Bool	Open a combo with an icon
comboItemLabel(text, align)	Bool	Item row; returns true when selected
comboItemSymbolLabel(symbol, text, align)	Bool	Icon + text item
comboClose()	—	Close the combo programmatically
comboEnd()	—	End combo; must be called if comboBegin* returned true

---

Groups

Groups are scrollable sub-regions inside a window.

if (Gui.beginGroup("Inventory", 0)) {  // flags=0
    // ...widgets...
    Gui.endGroup()
}

Method	Description
beginGroup(title, flags)	Start a group with a title
beginGroupTitled(name, title, flags)	Group with separate name and title
endGroup()	End the current group
groupGetScroll(id)	Returns [xOffset, yOffset] for a named group
groupSetScroll(id, x, y)	Set scroll position of a named group

---

Tree

Gui.treePush(type, title, state) / Gui.treePop()

type: 0 = node (collapsible branch), 1 = tab (tab-style). state: 0 = minimized, 1 = maximized (initial open state). Returns Bool; call treePop() only if true.

if (Gui.treePush(0, "Options", 1)) {
    Gui.layoutRowDynamic(20, 1)
    _sound = Gui.checkbox("Sound", _sound)
    Gui.treePop()
}

---

Popups

Popups are modal/non-modal overlay panels.

Method	Returns	Description
popupBegin(type, title, flags, x, y, w, h)	Bool	type: 0=static (modal), 1=dynamic (non-modal)
popupClose()	—	Close programmatically
popupEnd()	—	End popup; only if popupBegin returned true
popupGetScroll()	List [x, y]	Current scroll

---

Tooltips

Method	Description
tooltip(text)	Show a simple text tooltip on hover
tooltipBegin(width)	Begin a custom-content tooltip
tooltipEnd()	End the tooltip

---

Menus

Gui.menubarBegin()
if (Gui.menuBeginLabel("File", 0, 120, 200)) {
    Gui.layoutRowDynamic(25, 1)
    if (Gui.menuItemLabel("New", 0)) newFile()
    if (Gui.menuItemLabel("Save", 0)) saveFile()
    Gui.menuClose()
    Gui.menuEnd()
}
Gui.menubarEnd()

Method	Returns	Description
menubarBegin() / menubarEnd()	—	Wrap all menu items
menuBeginLabel(text, align, w, h)	Bool	Open a menu
menuBeginSymbol(text, symbol, w, h)	Bool	Open a menu with icon
menuItemLabel(text, align)	Bool	Item; true if selected
menuItemSymbolLabel(symbol, text, align)	Bool	Icon + text item
menuClose()	—	Close menu programmatically
menuEnd()	—	End menu

---

Contextual (right-click) menus

if (Gui.contextualBegin(0, 150, 200, mouseX, mouseY, 0, 0)) {
    Gui.layoutRowDynamic(25, 1)
    if (Gui.contextualItemLabel("Delete", 0)) deleteSelected()
    Gui.contextualEnd()
}

Method	Returns	Description
contextualBegin(flags, w, h, trigX, trigY, trigW, trigH)	Bool	Open on right-click within trigger rect
contextualItemLabel(text, align)	Bool	Item; true if selected
contextualItemSymbolLabel(symbol, text, align)	Bool	Icon + text item
contextualClose()	—	Close programmatically
contextualEnd()	—	End contextual

---

Charts

Gui.chartBegin(0, _values.count, 0, 1)    // 0 = line chart
for (v in _values) {
    Gui.chartPush(v)
}
Gui.chartEnd()

Method	Description
chartBegin(type, count, min, max)	type: 0=lines, 1=column. count = number of data points
chartBeginColored(type, r, g, b, a, ar, ag, ab, aa, count, min, max)	Same with custom main and highlight colors (0–255)
chartPush(value)	Add one data point
chartEnd()	End chart

---

Widget utilities

Method	Returns	Description
isWidgetHovered()	Bool	Mouse over last drawn widget
isWidgetClicked(button)	Bool	button: 0=left, 1=middle, 2=right
widgetBounds()	[x, y, w, h]	Bounds of the last drawn widget
isAnyItemActive()	Bool	Any widget is being interacted with
widgetDisableBegin()	—	Disable interaction for subsequent widgets
widgetDisableEnd()	—	Re-enable interaction

---

Custom drawing

Draw directly into the current window using Nuklear’s canvas commands. All coordinates are window-local. All color parameters are r, g, b, a in 0–255 integers.

Method	Description
drawLine(x0, y0, x1, y1, thickness, r, g, b, a)	Thick line segment
drawRect(x, y, w, h, rounding, thickness, r, g, b, a)	Outlined rectangle (rounding = corner radius px)
drawRectFilled(x, y, w, h, rounding, r, g, b, a)	Filled rectangle
drawCircle(x, y, w, h, thickness, r, g, b, a)	Outlined ellipse
drawCircleFilled(x, y, w, h, r, g, b, a)	Filled ellipse
drawTriangleFilled(x0, y0, x1, y1, x2, y2, r, g, b, a)	Filled triangle
drawArc(cx, cy, radius, aMin, aMax, thickness, r, g, b, a)	Arc stroke
drawArcFilled(cx, cy, radius, aMin, aMax, r, g, b, a)	Filled arc/pie
drawText(x, y, w, h, text, r, g, b, a)	Text at position
drawCurve(x0, y0, x1, y1, x2, y2, x3, y3, thickness, r, g, b, a)	Cubic bezier curve

// Draw a health bar
Gui.drawRectFilled(10, 10, 200, 16, 2, 50, 50, 50, 255)
Gui.drawRectFilled(10, 10, 200 * (_health / 100), 16, 2, 30, 220, 60, 255)

---

Theme & style

Method	Description
setTheme(name)	"dark" or "light" — switch the built-in theme
setAccentColor(r, g, b)	Override the primary accent color (0–255)
setRounding(pixels)	Corner rounding for buttons and windows
setWindowAlpha(alpha)	Window background opacity (0–1)
setFont(name, size)	Switch to a loaded font by name at the given point size
setFontSize(size)	Change size of the current font
loadFont(path, size, name)	Load a TTF font from path, at size points, and register it as name

Gui.setTheme("dark")
Gui.setAccentColor(0, 122, 255)    // 0-255
Gui.setRounding(4)
Gui.setWindowAlpha(0.9)            // 0-1
Gui.loadFont("fonts/inter.ttf", 16, "inter")
Gui.setFont("inter", 16)

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See Examples → GUI Overview for a minimal example, GUI Terminal for the in-game terminal and #!command attributes, and GUI Configurator for full Window API integration.