Fix embedded _NET_WM_ICON on X11

Previously the _NET_WM_ICON would use the .ico which was also used for
the Windows icon. This icon used the dimensions 256x256, but the maximum
supported image size is 192x192, so a new image with the dimensions
64x64 has been added.

Since we know the image format anyways, the `image` dependency could
also be easily replaced with `png`, which cuts out a few extra unused
dependencies.

Author: chrisduerr

Diff for: Cargo.lock

@@ -39,7 +39,7 @@ gl_generator = "0.14.0"
 xdg = "2"
 
 [target.'cfg(not(target_os = "macos"))'.dependencies]
-image = { version = "0.23.3", default-features = false, features = ["ico"], optional = true }
+png = { version = "0.16.8", default-features = false, optional = true }
 
 [target.'cfg(target_os = "macos")'.dependencies]
 objc = "0.2.2"
@@ -56,7 +56,7 @@ embed-resource = "1.3"
 
 [features]
 default = ["wayland", "x11"]
-x11 = ["copypasta/x11", "glutin/x11", "x11-dl", "image"]
+x11 = ["copypasta/x11", "glutin/x11", "x11-dl", "png"]
 wayland = ["copypasta/wayland", "glutin/wayland", "wayland-client"]
 winpty = ["alacritty_terminal/winpty"]
 nightly = []

Diff for: alacritty/Cargo.toml

@@ -0,0 +1 @@
+../extra/logo/compat/alacritty-term.png

Diff for: alacritty/alacritty.ico

@@ -19,8 +19,15 @@ use {
     crate::wayland_theme::AlacrittyWaylandTheme,
 };
 
+#[rustfmt::skip]
 #[cfg(all(feature = "x11", not(any(target_os = "macos", windows))))]
-use x11_dl::xlib::{Display as XDisplay, PropModeReplace, XErrorEvent, Xlib};
+use {
+    std::io::Cursor,
+
+    x11_dl::xlib::{Display as XDisplay, PropModeReplace, XErrorEvent, Xlib},
+    glutin::window::Icon,
+    png::Decoder,
+};
 
 use std::fmt::{self, Display, Formatter};
 
@@ -44,11 +51,11 @@ use crate::config::window::{Decorations, WindowConfig};
 use crate::config::Config;
 use crate::gl;
 
-// It's required to be in this directory due to the `windows.rc` file.
+/// Window icon for `_NET_WM_ICON` property.
 #[cfg(all(feature = "x11", not(any(target_os = "macos", windows))))]
-static WINDOW_ICON: &[u8] = include_bytes!("../alacritty.ico");
+static WINDOW_ICON: &[u8] = include_bytes!("../alacritty.png");
 
-// This should match the definition of IDI_ICON from `windows.rc`.
+/// This should match the definition of IDI_ICON from `windows.rc`.
 #[cfg(windows)]
 const IDI_ICON: WORD = 0x101;
 
@@ -257,11 +264,11 @@ impl Window {
     pub fn get_platform_window(title: &str, window_config: &WindowConfig) -> WindowBuilder {
         #[cfg(feature = "x11")]
         let icon = {
-            let image = image::load_from_memory_with_format(WINDOW_ICON, image::ImageFormat::Ico)
-                .expect("loading icon")
-                .to_rgba();
-            let (width, height) = image.dimensions();
-            glutin::window::Icon::from_rgba(image.into_raw(), width, height)
+            let decoder = Decoder::new(Cursor::new(WINDOW_ICON));
+            let (info, mut reader) = decoder.read_info().expect("invalid embedded icon");
+            let mut buf = vec![0; info.buffer_size()];
+            let _ = reader.next_frame(&mut buf);
+            Icon::from_rgba(buf, info.width, info.height)
         };
 
         let class = &window_config.class;