1use serde::Deserialize;
 2use ui::{px, Pixels};
 3
 4#[derive(Debug, 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, mut visible_line_count: f32) -> f32 {
14        match self {
15            Self::Line(count) => *count,
16            Self::Page(count) => {
17                // for full pages subtract one to leave an anchor line
18                if count.abs() == 1.0 {
19                    visible_line_count -= 1.0
20                }
21                (visible_line_count * count).trunc()
22            }
23        }
24    }
25
26    pub fn pixels(&self, line_height: Pixels, height: Pixels) -> Pixels {
27        match self {
28            ScrollAmount::Line(x) => px(line_height.0 * x),
29            ScrollAmount::Page(x) => px(height.0 * x),
30        }
31    }
32}