Struct ScrollBase

pub struct ScrollBase {
    pub start_line: usize,
    pub content_height: usize,
    pub view_height: usize,
    pub scrollbar_offset: usize,
    pub right_padding: usize,
    pub thumb_grab: Option<usize>,
}

👎Deprecated since 0.16.0: ScrollBase is being deprecated in favor of the view::scroll module.

Provide scrolling functionalities to a view.

This is a legacy helper utility to define scrollable views.

The scroll module is the preferred way to achieve that.

Fields

start_line: usize

👎Deprecated since 0.16.0: ScrollBase is being deprecated in favor of the view::scroll module.

First line visible

content_height: usize

👎Deprecated since 0.16.0: ScrollBase is being deprecated in favor of the view::scroll module.

Content height

view_height: usize

👎Deprecated since 0.16.0: ScrollBase is being deprecated in favor of the view::scroll module.

Number of lines displayed

scrollbar_offset: usize

👎Deprecated since 0.16.0: ScrollBase is being deprecated in favor of the view::scroll module.

Padding for the scrollbar

If present, the scrollbar will be shifted scrollbar_offset columns to the left.

(Useful when each item includes its own side borders, to draw the scrollbar inside.)

right_padding: usize

👎Deprecated since 0.16.0: ScrollBase is being deprecated in favor of the view::scroll module.

Blank between the text and the scrollbar.

thumb_grab: Option<usize>

👎Deprecated since 0.16.0: ScrollBase is being deprecated in favor of the view::scroll module.

Initial position of the cursor when dragging.

Implementations

impl ScrollBase

pub fn new() -> Self

Creates a new, uninitialized scrollbar.

pub fn scrollbar_offset(self, offset: usize) -> Self

Shifts the scrollbar toward the inside of the view.

Used by views that draw their side borders in the children. Pushing the scrollbar to the left allows it to stay inside the borders.

pub fn right_padding(self, padding: usize) -> Self

Sets the number of blank cells between the text and the scrollbar.

Defaults to 1.

pub fn set_heights(&mut self, view_height: usize, content_height: usize)

Call this method when the content or the view changes.

pub fn scrollable(&self) -> bool

Returns TRUE if the view needs to scroll.

pub fn can_scroll_up(&self) -> bool

Returns TRUE unless we are at the top.

pub fn can_scroll_down(&self) -> bool

Returns TRUE unless we are at the bottom.

pub fn scroll_top(&mut self)

Scroll to the top of the view.

pub fn scroll_to(&mut self, y: usize)

Makes sure that the given line is visible, scrolling if needed.

pub fn scroll_bottom(&mut self)

Scroll to the bottom of the view.

pub fn scroll_down(&mut self, n: usize)

Scroll down by the given number of line.

Never further than the bottom of the view.

pub fn scroll_to_thumb(&mut self, thumb_y: usize, thumb_height: usize)

Scrolls down until the scrollbar thumb is at the given location.

pub fn scroll_up(&mut self, n: usize)

Scroll up by the given number of lines.

Never above the top of the view.

pub fn start_drag(&mut self, position: Vec2, width: usize) -> bool

Starts scrolling from the given cursor position.

pub fn drag(&mut self, position: Vec2)

Keeps scrolling by dragging the cursor.

pub fn is_dragging(&self) -> bool

Returns true if we are in the process of dragging the scroll thumb.

pub fn release_grab(&mut self)

Stops grabbing the scrollbar.

pub fn draw<F>(&self, printer: &Printer<'_, '_>, line_drawer: F)

where F: Fn(&Printer<'_, '_>, usize),

Draws the scroll bar and the content using the given drawer.

line_drawer will be called once for each line that needs to be drawn. It will be given the absolute ID of the item to draw.. It will also be given a printer with the correct offset, so it should only print on the first line.

Examples

let lines = ["Line 1", "Line number 2"];
scrollbase.draw(printer, |printer, i| {
    printer.print((0, 0), lines[i]);
});

pub fn scrollbar_x(&self, total_size: usize) -> usize

Returns the X position of the scrollbar, given the size available.

Note that this does not depend whether or not a scrollbar will actually be present.

pub fn scrollbar_thumb_height(&self) -> usize

Returns the height of the scrollbar thumb.

pub fn scrollbar_thumb_y(&self, scrollbar_thumb_height: usize) -> usize

Returns the y position of the scrollbar thumb.

Trait Implementations

impl Debug for ScrollBase

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

Formats the value using the given formatter.

impl Default for ScrollBase

fn default() -> ScrollBase

Returns the “default value” for a type.