Struct ScrollDimensions 

pub struct ScrollDimensions { /* private fields */ }

ScrollDimensions - Centralizes ALL scrolling and scrollbar mathematical operations

Eliminates ad hoc scrollbar math like:

• knob_size = std::cmp::max(1, (track_height as f64 * content_ratio).round() as usize)
• available_track = track_height.saturating_sub(knob_size)
• knob_position = ((scroll / 100.0) * available_track as f64).round() as usize
• All coordinate translation between scroll percentages and pixel positions

Replaces scattered scrollbar logic from vertical_scrollbar.rs, horizontal_scrollbar.rs, draw_loop.rs scrollbar detection, and box_renderer.rs scroll calculations.

Implementations

impl ScrollDimensions

pub fn new( content_size: (usize, usize), viewable_size: (usize, usize), scroll_position: (f64, f64), parent_bounds: Bounds, ) -> Self

Create new scroll dimensions

pub fn set_scroll_position(&mut self, horizontal: f64, vertical: f64)

Update scroll position (with automatic clamping)

pub fn is_scrollbar_needed(&self, orientation: Orientation) -> bool

Check if scrollbar is needed for given orientation Replaces: content_height > viewable_height checks

pub fn get_track_bounds(&self, orientation: Orientation) -> TrackBounds

Get scrollbar track bounds (where scrollbar can be drawn) Centralizes track positioning logic from scrollbar components

pub fn calculate_knob_size(&self, orientation: Orientation) -> usize

Calculate scrollbar knob size Centralizes: knob_size = std::cmp::max(1, (track_length as f64 * content_ratio).round() as usize)

pub fn calculate_knob_position(&self, orientation: Orientation) -> usize

Calculate scrollbar knob position within track Centralizes: knob_position = ((scroll / 100.0) * available_track as f64).round() as usize

pub fn get_knob_bounds(&self, orientation: Orientation) -> KnobBounds

Get absolute knob bounds for drawing Centralizes knob positioning from scrollbar components

pub fn calculate_scroll_offset(&self, orientation: Orientation) -> usize

Calculate scroll offset in content coordinates Centralizes: offset = ((scroll / 100.0) * max_offset as f64).floor() as usize

pub fn pixel_to_scroll_percent( &self, pixel_coordinate: usize, orientation: Orientation, ) -> f64

Convert pixel position within track to scroll percentage Centralizes click-to-scroll calculations from draw_loop.rs

pub fn hits_knob(&self, x: usize, y: usize, orientation: Orientation) -> bool

Test if coordinate hits the scrollbar knob Centralizes knob hit testing from draw_loop.rs

pub fn hits_track(&self, x: usize, y: usize, orientation: Orientation) -> bool

Test if coordinate hits the scrollbar track (but not knob) Centralizes track click detection for jump-to-position

pub fn calculate_drag_scroll( &self, start_pixel: usize, current_pixel: usize, orientation: Orientation, ) -> f64

Calculate new scroll percentage from knob drag operation Centralizes drag-to-scroll calculations

pub fn get_visible_range(&self, orientation: Orientation) -> (usize, usize)

Get visible content range (start, end) for given orientation
Centralizes visible range calculations for content clipping

pub fn calculate_auto_scroll_to_line( &self, target_line: usize, orientation: Orientation, ) -> f64

Calculate auto-scroll adjustment to keep target line visible Centralizes auto-scroll logic from draw_loop.rs choice navigation

Trait Implementations

impl Clone for ScrollDimensions

fn clone(&self) -> ScrollDimensions

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ScrollDimensions

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.