#[derive(Debug, Clone, Copy)]
pub enum ScrollCommand {
Lines(i32),
Pages(i32),
}
impl ScrollCommand {
pub fn to_lines(self, page_height: usize) -> i32 {
match self {
Self::Lines(n) => n,
Self::Pages(n) => n * page_height as i32,
}
}
/// compute the new scroll value
pub fn apply(self, scroll: usize, content_height: usize, page_height: usize) -> usize {
(scroll as i32 + self.to_lines(page_height))
.min(content_height as i32 - page_height as i32 + 1)
.max(0) as usize
}
}