1use crate::Editor;
 2use serde::Deserialize;
 3
 4#[derive(Clone, PartialEq, Deserialize)]
 5pub enum ScrollAmount {
 6    // Scroll N lines (positive is towards the end of the document)
 7    Line(f32),
 8    // Scroll N pages (positive is towards the end of the document)
 9    Page(f32),
10}
11
12impl ScrollAmount {
13    pub fn lines(&self, editor: &mut Editor) -> f32 {
14        match self {
15            Self::Line(count) => *count,
16            Self::Page(count) => editor
17                .visible_line_count()
18                .map(|mut l| {
19                    // for full pages subtract one to leave an anchor line
20                    if count.abs() == 1.0 {
21                        l -= 1.0
22                    }
23                    (l * count).trunc()
24                })
25                .unwrap_or(0.),
26        }
27    }
28}