open a splash window instead

Cargo.lock

@@ -378,6 +378,7 @@ dependencies = [
  "png 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "structopt 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "x11 2.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]

Cargo.toml

@@ -14,8 +14,9 @@ failure = "0.1"
 gl = "0.10"
 glutin = "0.18"
 imlib2 = { version = "0.1", path = "./imlib2" }
+leanshot_xlib = { version = "0.1", path = "./xlib" }
 nanovg = { version = "1.0.2", features = ["gl3"] }
 png = "0.12"
 structopt = "0.2"
 time = "0.1"
-leanshot_xlib = { version = "0.1", path = "./xlib" }
+x11 = { version = "2.18", features = ["xlib"] }

src/gui.rs

@@ -1,5 +1,5 @@
 use imlib2::{self, Image as Image2};
-use xlib::{Display, Visual, Window};
+use xlib::{self, Display, Visual, Window};
 
 use errors::ScreenshotError;
 use Options;
@@ -116,7 +116,25 @@ impl GUI {
             .with_multisampling(4)
             .with_srgb(true);
         let win = GlWindow::new(wb, ctx, &evl).expect("couldn't make window");
+
+        // crosshair
         win.set_cursor(MouseCursor::Crosshair);
+
+        // change window type
+        {
+            use glutin::os::unix::WindowExt;
+            use xlib::Atom;
+            match win.get_xlib_window() {
+                Some(id) => {
+                    let w = Window::create_from_handle(&self.display, id)?;
+                    let key = Atom::new(&self.display, "_NET_WM_WINDOW_TYPE", false)?;
+                    let val = Atom::new(&self.display, "_NET_WM_WINDOW_TYPE_SPLASH", false)?;
+                    w.change_property(&key, &val);
+                }
+                _ => (),
+            }
+        }
+
         let f = win.get_hidpi_factor() as f64;
         unsafe {
             win.make_current().expect("couldn't make window");

src/main.rs

@@ -13,6 +13,7 @@ extern crate png;
 extern crate structopt;
 extern crate leanshot_xlib as xlib;
 extern crate time;
+extern crate x11;
 
 mod capture;
 mod errors;

xlib/src/atom.rs

@@ -0,0 +1,38 @@
+use std::ffi::CString;
+use x11::xlib as x;
+
+use Display;
+use X11Error;
+
+/// A unique string or intger
+pub struct Atom {
+    inner: x::Atom,
+}
+
+impl Atom {
+    /// Create a new atom using a string
+    pub fn new(
+        display: &Display,
+        val: impl AsRef<str>,
+        only_if_exists: bool,
+    ) -> Result<Self, X11Error> {
+        let val = {
+            let v = val.as_ref();
+            let s = CString::new(v).unwrap();
+            s.as_ptr()
+        };
+        let inner =
+            unsafe { x::XInternAtom(display.as_raw(), val, if only_if_exists { 1 } else { 0 }) };
+        Ok(Atom { inner })
+    }
+
+    /// Create a new Atom object from an existing handle
+    pub fn from(handle: x::Atom) -> Self {
+        Atom { inner: handle }
+    }
+
+    /// Get the handle
+    pub fn as_raw(&self) -> x::Atom {
+        self.inner
+    }
+}

xlib/src/lib.rs

@@ -5,8 +5,9 @@
 #[macro_use]
 extern crate failure;
 extern crate libc;
-extern crate x11;
+pub extern crate x11;
 
+mod atom;
 mod cursor;
 mod display;
 mod drawable;
@@ -21,6 +22,7 @@ mod window;
 #[allow(missing_docs)]
 mod cursorfont;
 
+pub use atom::Atom;
 pub use cursor::Cursor;
 pub use cursorfont::*;
 pub use display::{Display, GetDisplay};

xlib/src/window.rs

@@ -4,7 +4,7 @@ use std::mem;
 use libc;
 use x11::xlib as x;
 
-use {Display, Drawable, GetDisplay, Image, Rectangle, X11Error};
+use {Atom, Display, Drawable, GetDisplay, Image, Rectangle, X11Error};
 
 /// A wrapper around a window handle.
 #[derive(Copy, Clone, PartialEq, Eq)]
@@ -53,6 +53,14 @@ impl Window {
         })
     }
 
+    /// Create a new Window instance from an existing ID
+    pub fn create_from_handle(display: &Display, id: u64) -> Result<Window, X11Error> {
+        Ok(Window {
+            display: display.as_raw(),
+            inner: id,
+        })
+    }
+
     /// Get window attributes.
     pub fn get_attributes(&self) -> Result<WindowAttributes, X11Error> {
         let attr = unsafe {
@@ -86,6 +94,25 @@ impl Window {
             ),
         )
     }
+
+    /// Change window property
+    // TODO: make it more general
+    pub fn change_property(&self, key: &Atom, val: &Atom) {
+        use std::mem::transmute;
+        let v = val.as_raw();
+        unsafe {
+            x::XChangeProperty(
+                self.display,
+                self.inner,
+                key.as_raw(),
+                x::XA_ATOM,
+                32,
+                x::PropModeReplace,
+                transmute(&v),
+                1,
+            );
+        }
+    }
 }
 
 impl GetDisplay for Window {