133 lines
4.4 KiB
Rust
133 lines
4.4 KiB
Rust
use std::cell::RefCell;
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use std::collections::hash_map::{Entry, HashMap};
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use std::error::Error;
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use x11::{xlib, xlib::Display, xlib_xcb};
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use x11rb::connection::Connection;
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use x11rb::cursor::Handle as CursorHandle;
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use x11rb::protocol::xproto::{Cursor, Screen};
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use x11rb::resource_manager;
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use x11rb::xcb_ffi::XCBConnection;
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use crate::MouseCursor;
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use super::cursor;
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x11rb::atom_manager! {
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pub Atoms: AtomsCookie {
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WM_PROTOCOLS,
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WM_DELETE_WINDOW,
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}
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}
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/// A very light abstraction around the XCB connection.
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///
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/// Keeps track of the xcb connection itself and the xlib display ID that was used to connect.
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pub struct XcbConnection {
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pub(crate) dpy: *mut Display,
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pub(crate) conn: XCBConnection,
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pub(crate) screen: usize,
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pub(crate) atoms: Atoms,
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pub(crate) resources: resource_manager::Database,
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pub(crate) cursor_handle: CursorHandle,
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pub(super) cursor_cache: RefCell<HashMap<MouseCursor, u32>>,
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}
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impl XcbConnection {
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pub fn new() -> Result<Self, Box<dyn Error>> {
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let dpy = unsafe { xlib::XOpenDisplay(std::ptr::null()) };
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assert!(!dpy.is_null());
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let xcb_connection = unsafe { xlib_xcb::XGetXCBConnection(dpy) };
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assert!(!xcb_connection.is_null());
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let screen = unsafe { xlib::XDefaultScreen(dpy) } as usize;
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let conn = unsafe { XCBConnection::from_raw_xcb_connection(xcb_connection, false)? };
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unsafe {
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xlib_xcb::XSetEventQueueOwner(dpy, xlib_xcb::XEventQueueOwner::XCBOwnsEventQueue)
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};
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let atoms = Atoms::new(&conn)?.reply()?;
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let resources = resource_manager::new_from_default(&conn)?;
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let cursor_handle = CursorHandle::new(&conn, screen, &resources)?.reply()?;
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Ok(Self {
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dpy,
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conn,
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screen,
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atoms,
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resources,
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cursor_handle,
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cursor_cache: RefCell::new(HashMap::new()),
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})
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}
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// Try to get the scaling with this function first.
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// If this gives you `None`, fall back to `get_scaling_screen_dimensions`.
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// If neither work, I guess just assume 96.0 and don't do any scaling.
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fn get_scaling_xft(&self) -> Result<Option<f64>, Box<dyn Error>> {
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if let Some(dpi) = self.resources.get_value::<u32>("Xft.dpi", "")? {
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Ok(Some(dpi as f64 / 96.0))
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} else {
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Ok(None)
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}
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}
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// Try to get the scaling with `get_scaling_xft` first.
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// Only use this function as a fallback.
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// If neither work, I guess just assume 96.0 and don't do any scaling.
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fn get_scaling_screen_dimensions(&self) -> f64 {
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// Figure out screen information
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let screen = self.screen();
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// Get the DPI from the screen struct
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//
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// there are 2.54 centimeters to an inch; so there are 25.4 millimeters.
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// dpi = N pixels / (M millimeters / (25.4 millimeters / 1 inch))
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// = N pixels / (M inch / 25.4)
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// = N * 25.4 pixels / M inch
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let width_px = screen.width_in_pixels as f64;
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let width_mm = screen.width_in_millimeters as f64;
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let height_px = screen.height_in_pixels as f64;
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let height_mm = screen.height_in_millimeters as f64;
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let _xres = width_px * 25.4 / width_mm;
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let yres = height_px * 25.4 / height_mm;
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// TODO: choose between `xres` and `yres`? (probably both are the same?)
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yres / 96.0
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}
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#[inline]
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pub fn get_scaling(&self) -> Result<f64, Box<dyn Error>> {
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Ok(self.get_scaling_xft()?.unwrap_or(self.get_scaling_screen_dimensions()))
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}
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#[inline]
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pub fn get_cursor(&self, cursor: MouseCursor) -> Result<Cursor, Box<dyn Error>> {
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// PANIC: this function is the only point where we access the cache, and we never call
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// external functions that may make a reentrant call to this function
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let mut cursor_cache = self.cursor_cache.borrow_mut();
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match cursor_cache.entry(cursor) {
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Entry::Occupied(entry) => Ok(*entry.get()),
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Entry::Vacant(entry) => {
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let cursor =
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cursor::get_xcursor(&self.conn, self.screen, &self.cursor_handle, cursor)?;
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entry.insert(cursor);
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Ok(cursor)
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}
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}
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}
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pub fn screen(&self) -> &Screen {
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&self.conn.setup().roots[self.screen]
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}
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}
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impl Drop for XcbConnection {
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fn drop(&mut self) {
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unsafe {
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xlib::XCloseDisplay(self.dpy);
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}
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}
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}
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