smithay/anvil/src/cursor.rs

93 lines
2.6 KiB
Rust

use std::io::Read;
use xcursor::{
parser::{parse_xcursor, Image},
CursorTheme,
};
static FALLBACK_CURSOR_DATA: &[u8] = include_bytes!("../resources/cursor.rgba");
pub struct Cursor {
icons: Vec<Image>,
size: u32,
}
impl Cursor {
pub fn load(log: &::slog::Logger) -> Cursor {
let name = std::env::var("XCURSOR_THEME")
.ok()
.unwrap_or_else(|| "default".into());
let size = std::env::var("XCURSOR_SIZE")
.ok()
.and_then(|s| s.parse().ok())
.unwrap_or(24);
let theme = CursorTheme::load(&name);
let icons = load_icon(&theme)
.map_err(|err| slog::warn!(log, "Unable to load xcursor: {}, using fallback cursor", err))
.unwrap_or_else(|_| {
vec![Image {
size: 32,
width: 64,
height: 64,
xhot: 1,
yhot: 1,
delay: 1,
pixels_rgba: Vec::from(FALLBACK_CURSOR_DATA),
pixels_argb: vec![], //unused
}]
});
Cursor { icons, size }
}
pub fn get_image(&self, scale: u32, millis: u32) -> Image {
let size = self.size * scale;
frame(millis, size, &self.icons)
}
}
fn nearest_images(size: u32, images: &[Image]) -> impl Iterator<Item = &Image> {
// Follow the nominal size of the cursor to choose the nearest
let nearest_image = images
.iter()
.min_by_key(|image| (size as i32 - image.size as i32).abs())
.unwrap();
images
.iter()
.filter(move |image| image.width == nearest_image.width && image.height == nearest_image.height)
}
fn frame(mut millis: u32, size: u32, images: &[Image]) -> Image {
let total = nearest_images(size, images).fold(0, |acc, image| acc + image.delay);
millis %= total;
for img in nearest_images(size, images) {
if millis < img.delay {
return img.clone();
}
millis -= img.delay;
}
unreachable!()
}
#[derive(thiserror::Error, Debug)]
enum Error {
#[error("Theme has no default cursor")]
NoDefaultCursor,
#[error("Error opening xcursor file: {0}")]
File(#[from] std::io::Error),
#[error("Failed to parse XCursor file")]
Parse,
}
fn load_icon(theme: &CursorTheme) -> Result<Vec<Image>, Error> {
let icon_path = theme.load_icon("default").ok_or(Error::NoDefaultCursor)?;
let mut cursor_file = std::fs::File::open(&icon_path)?;
let mut cursor_data = Vec::new();
cursor_file.read_to_end(&mut cursor_data)?;
parse_xcursor(&cursor_data).ok_or(Error::Parse)
}