core.scrollbar

Scrollable viewport indicator with draggable thumb. Supports both vertical and horizontal orientation with configurable alignment. Uses a "normal" coordinate system internally that treats all scrollbars as vertical-end-aligned, then transforms to the actual orientation/alignment.

local scrollbar = require "core.scrollbar"

__index​

(field) __index: core.object

Base class providing OOP functionality for Lua. All classes in Pragtical inherit from Object.

alignment​

(field) alignment: "e"|"s"

Start or end position (left/top vs right/bottom)

contracted_margin​

(field) contracted_margin: number?

Override for style.contracted_scrollbar_margin

contracted_size​

(field) contracted_size: number?

Override for style.scrollbar_size

direction​

(field) direction: "h"|"v"

Vertical or horizontal orientation

drag_start_offset​

(field) drag_start_offset: number

Offset from thumb top when drag started

dragging​

(field) dragging: boolean

True when user is dragging the thumb

expand_percent​

(field) expand_percent: number

Animation state [0-1] for hover expansion

expanded_margin​

(field) expanded_margin: number?

Override for style.expanded_scrollbar_margin

expanded_size​

(field) expanded_size: number?

Override for style.expanded_scrollbar_size

force_status​

(field) force_status: ("contracted"|"expanded"|false)?

Forced display state

minimum_thumb_size​

(field) minimum_thumb_size: number?

Override for style.minimum_thumb_size

percent​

(field) percent: number

Scroll position [0-1]

super​

(field) super: core.object

Base class providing OOP functionality for Lua. All classes in Pragtical inherit from Object.

core.scrollbar.hovering​

thumb​

(field) thumb: boolean

True if mouse is over thumb

track​

(field) track: boolean

True if mouse is over track

core.scrollbar.normal_rect​

across​

(field) across: number

Position perpendicular to scroll direction

across_size​

(field) across_size: number

Size perpendicular to scroll direction

along​

(field) along: number

Position parallel to scroll direction

along_size​

(field) along_size: number

Size parallel to scroll direction

scrollable​

(field) scrollable: number

Total scrollable size

core.scrollbar.options​

Configuration options for creating a scrollbar.

alignment​

(field) alignment: ("e"|"s")?

Start or End - left/top vs right/bottom (default: "e")

contracted_margin​

(field) contracted_margin: number?

Override style.contracted_scrollbar_margin

contracted_size​

(field) contracted_size: number?

Override style.scrollbar_size

direction​

(field) direction: ("h"|"v")?

Vertical or Horizontal (default: "v")

expanded_margin​

(field) expanded_margin: number?

Override style.expanded_scrollbar_margin

expanded_size​

(field) expanded_size: number?

Override style.expanded_scrollbar_size

force_status​

(field) force_status: ("contracted"|"expanded"|false)?

Force display state

minimum_thumb_size​

(field) minimum_thumb_size: number?

Override style.minimum_thumb_size

core.scrollbar.rect​

h​

(field) h: number

scrollable​

(field) scrollable: number

Total scrollable size

w​

(field) w: number

x​

(field) x: number

y​

(field) y: number

__call​

(method) core.object:__call(...any)
  -> obj: core.object

Metamethod allowing class to be called like a constructor. Enables syntax: local obj = MyClass(args) instead of MyClass:new(args) Automatically creates instance and calls new() with provided arguments.

@return obj — The new instance of the class

__tostring​

(method) core.scrollbar:__tostring()
  -> string

_get_thumb_rect_normal​

(method) core.scrollbar:_get_thumb_rect_normal()
  -> x: number
  2. y: number
  3. w: number
  4. h: number

Get thumb rectangle in normalized coordinates. Internal helper - use get_thumb_rect() for real coordinates.

@return x — Normalized x coordinate

@return y — Normalized y coordinate

@return w — Normalized width

@return h — Normalized height

_get_track_rect_normal​

(method) core.scrollbar:_get_track_rect_normal()
  -> x: number
  2. y: number
  3. w: number
  4. h: number

Get track rectangle in normalized coordinates. Internal helper - use get_track_rect() for real coordinates.

@return x — Normalized x coordinate

@return y — Normalized y coordinate

@return w — Normalized width

@return h — Normalized height

_on_mouse_moved_normal​

(method) core.scrollbar:_on_mouse_moved_normal(x: number, y: number, dx: number, dy: number)
  -> result: boolean|number

Handle mouse movement in normalized coordinates. Internal helper - use on_mouse_moved() for real coordinates.

@param x — Normalized x coordinate

@param y — Normalized y coordinate

@param dx — Normalized delta x

@param dy — Normalized delta y

@return result — True if hovering, 0-1 percent if dragging, falsy otherwise

_on_mouse_pressed_normal​

(method) core.scrollbar:_on_mouse_pressed_normal(button: 'left'|'right', x: number, y: number, clicks: integer)
  -> result: boolean|number

Handle mouse press in normalized coordinates. Internal helper - use on_mouse_pressed() for real coordinates.

@param x — Normalized x coordinate

@param y — Normalized y coordinate

@param clicks — Number of clicks

@return result — True if thumb clicked, 0-1 percent if track clicked, falsy otherwise

button:
    | 'left'
    | 'right'

_on_mouse_released_normal​

(method) core.scrollbar:_on_mouse_released_normal(button: 'left'|'right', x: number, y: number)
  -> hovering: boolean

Handle mouse release in normalized coordinates. Internal helper - use on_mouse_released() for real coordinates.

@param x — Normalized x coordinate

@param y — Normalized y coordinate

@return hovering — True if hovering track or thumb

button:
    | 'left'
    | 'right'

_overlaps_normal​

(method) core.scrollbar:_overlaps_normal(x: number, y: number)
  -> part: "thumb"|"track"|nil

Check what part of scrollbar overlaps a point in normalized coordinates. Internal helper - use overlaps() for real coordinates.

@param x — Normalized x coordinate

@param y — Normalized y coordinate

@return part — What was hit, or nil if nothing

part:
    | "thumb"
    | "track"

_update_hover_status_normal​

(method) core.scrollbar:_update_hover_status_normal(x: number, y: number)
  -> hovering: boolean

Update hover status in normalized coordinates. Internal helper called by other mouse methods.

@param x — Normalized x coordinate

@param y — Normalized y coordinate

@return hovering — True if hovering track or thumb

draw​

(method) core.scrollbar:draw()

Draw the complete scrollbar (track and thumb). Call this from the owning view's draw() method.

draw_thumb​

(method) core.scrollbar:draw_thumb()

Draw the scrollbar thumb (draggable indicator). Highlights when hovered or being dragged.

draw_track​

(method) core.scrollbar:draw_track()

Draw the scrollbar track (background). Only draws when hovered/dragging or expanded. Fades in based on expand_percent animation.

extend​

(method) core.object:extend()
  -> cls: core.object

Create a new class that inherits from this one. Returns a new class with this class as its parent. Example: local MyClass = Object:extend()

@return cls — The new class table

extends​

(method) core.object:extends(T: any)
  -> extends: boolean

Check if object inherits from the given type (inheritance-aware). Use this to check class hierarchy. Example: view:extends(View) returns true for View and all subclasses

@param T — Class to check inheritance from

@return extends — True if object is T or inherits from T

get_thumb_rect​

(method) core.scrollbar:get_thumb_rect()
  -> x: number
  2. y: number
  3. w: number
  4. h: number

Get the thumb rectangle (the draggable part of the scrollbar).

@return x — Screen x coordinate

@return y — Screen y coordinate

@return w — Width in pixels

@return h — Height in pixels

get_track_rect​

(method) core.scrollbar:get_track_rect()
  -> x: number
  2. y: number
  3. w: number
  4. h: number

Get the track rectangle (the background of the scrollbar).

@return x — Screen x coordinate

@return y — Screen y coordinate

@return w — Width in pixels

@return h — Height in pixels

is​

(method) core.object:is(T: any)
  -> is_exact: boolean

Check if object is exactly of the given type (no inheritance check). Use this for strict type matching. Example: view:is(DocView) returns true only if view is a DocView, not a subclass

@param T — Class to check against

@return is_exact — True if object is exactly type T

is_class_of​

(method) core.object:is_class_of(T: any)
  -> is_instance: boolean

Check if the given object is exactly an instance of this class. Inverse of is() - checks if T is an instance of self. Example: DocView:is_class_of(obj) checks if obj is exactly a DocView

@param T — Object to check

@return is_instance — True if T is exactly an instance of this class

is_extended_by​

(method) core.object:is_extended_by(T: any)
  -> is_extended: boolean

Check if the given object/class inherits from this class. Inverse of extends() - checks if T is a subclass of self. Example: View:is_extended_by(DocView) checks if DocView inherits from View

@param T — Object or class to check

@return is_extended — True if T inherits from this class

new​

(method) core.scrollbar:new(options: core.scrollbar.options)

Constructor - initializes a scrollbar with specified orientation and style.

@param options — Configuration options

normal_to_real​

(method) core.scrollbar:normal_to_real(x?: number, y?: number, w?: number, h?: number)
  -> x: number
  2. y: number
  3. w: number
  4. h: number

Transform normalized coordinates back to real coordinate system. Internal helper for orientation/alignment handling.

@param x — Normalized x coordinate

@param y — Normalized y coordinate

@param w — Normalized width

@param h — Normalized height

@return x — Real x

@return y — Real y

@return w — Real width

@return h — Real height

on_mouse_left​

(method) core.scrollbar:on_mouse_left()

Handle mouse leaving the scrollbar area. Clears all hover states.

on_mouse_moved​

(method) core.scrollbar:on_mouse_moved(x: number, y: number, dx: number, dy: number)
  -> result: (boolean|number)?

Handle mouse movement events on the scrollbar. Updates hover status and returns drag position if dragging. Does NOT automatically update scroll position - caller must use set_percent().

@param x — Screen x coordinate

@param y — Screen y coordinate

@param dx — Delta x since last move

@param dy — Delta y since last move

@return result — True if hovering, 0-1 percent if dragging, falsy otherwise

on_mouse_pressed​

(method) core.scrollbar:on_mouse_pressed(button: 'left'|'right', x: number, y: number, clicks: integer)
  -> result: (boolean|number)?

Handle mouse press events on the scrollbar. Sets dragging state if thumb is clicked. Does NOT automatically update scroll position - caller must use set_percent().

@param button — Mouse button

@param x — Screen x coordinate

@param y — Screen y coordinate

@param clicks — Number of clicks

@return result — True if thumb clicked, 0-1 percent if track clicked, falsy otherwise

button:
    | 'left'
    | 'right'

on_mouse_released​

(method) core.scrollbar:on_mouse_released(button: 'left'|'right', x: number, y: number)
  -> hovering: boolean?

Handle mouse release events on the scrollbar. Clears dragging state and updates hover status.

@param button — Mouse button

@param x — Screen x coordinate

@param y — Screen y coordinate

@return hovering — True if hovering track or thumb

button:
    | 'left'
    | 'right'

overlaps​

(method) core.scrollbar:overlaps(x: number, y: number)
  -> part: "thumb"|"track"|nil

Check what part of the scrollbar overlaps a screen point.

@param x — Screen x coordinate

@param y — Screen y coordinate

@return part — What was hit, or nil if nothing

part:
    | "thumb"
    | "track"

real_to_normal​

(method) core.scrollbar:real_to_normal(x?: number, y?: number, w?: number, h?: number)
  -> x: number
  2. y: number
  3. w: number
  4. h: number

Transform real coordinates to normalized coordinate system. Internal helper for orientation/alignment handling.

@param x — Real x coordinate

@param y — Real y coordinate

@param w — Real width

@param h — Real height

@return x — Normalized x

@return y — Normalized y

@return w — Normalized width

@return h — Normalized height

set_forced_status​

(method) core.scrollbar:set_forced_status(status: "contracted"|"expanded"|false)

Set the forced display status of the scrollbar. When forced, the scrollbar won't animate based on hover state.

@param status — Status to force (false to allow auto-animation)

status:
    | "expanded"
    | "contracted"
    | false

set_percent​

(method) core.scrollbar:set_percent(percent: number)

Set the scrollbar thumb position.

@param percent — Position from 0-1 (0 = top/left, 1 = bottom/right)

set_size​

(method) core.scrollbar:set_size(x: number, y: number, w: number, h: number, scrollable: number)

Set the bounding box of the view this scrollbar belongs to. Must be called when view size or scrollable area changes.

@param x — View x position

@param y — View y position

@param w — View width

@param h — View height

@param scrollable — Total scrollable size (height for vertical, width for horizontal)

update​

(method) core.scrollbar:update()

Update scrollbar animations (hover expansion). Call this every frame to animate the scrollbar width on hover.