Set images as wallpaper

- Hard-coded image path

src/main.rs

@@ -1,4 +1,4 @@
-use anyhow::Result;
+use anyhow::{Context, Result};
 use std::thread;
 use std::time::Duration;
 use x11rb::wrapper::ConnectionExt as _;
@@ -6,12 +6,16 @@ use x11rb::{
     connection::Connection,
     protocol::xproto::{
         AtomEnum, ChangeWindowAttributesAux, CloseDown, ConnectionExt, CreateGCAux, EventMask,
-        PropMode, Rectangle,
+        ImageFormat, PropMode,
     },
     rust_connection::RustConnection,
 };
 
 fn main() -> Result<()> {
+    // Path to wallpaper image.
+    // This is hardcoded for now and will later be replaced by config loading.
+    let image_path = "/path/to/image";
+
     // Connect to the running graphical session, the X11 server.
     let (conn, screen_num) = RustConnection::connect(None)?;
     // Select the current screen.
@@ -54,30 +58,54 @@ fn main() -> Result<()> {
     let pixmap = conn.generate_id()?;
     conn.create_pixmap(depth, pixmap, root, width, height)?;
 
-    // Fill the pixmap with the pixels to be set as the background.
-    // For now, allocate a solid color (RGB 26,132,74 scaled to X11 16-bit format).
-    let color = conn
-        .alloc_color(screen.default_colormap, 26 * 257, 132 * 257, 74 * 257)?
-        .reply()?
-        .pixel;
+    // Load the wallpaper image from disk.
+    let img =
+        image::open(image_path).with_context(|| format!("Failed to open image: {image_path}"))?;
 
-    // Create a Graphics Context (GC), which defines how drawing is done.
-    // It stores drawing parameters such as color, fill style, etc.
+    // Convert the image into RGBA8 (4 bytes per pixel).
+    // Predictable, CPU-friendly format to work on.
+    let img = img.to_rgba8();
+
+    // Resize the image to exactly match the screen size.
+    // This uses a simple "fill" strategy (no aspect ratio preservation).
+    let img = image::imageops::resize(
+        &img,
+        width.into(),
+        height.into(),
+        image::imageops::FilterType::Lanczos3,
+    );
+
+    // Extract raw pixel bytes from the image buffer.
+    let mut pixel_data = img.into_raw();
+
+    // Image libraries produce RGBA, but X11 TrueColor visuals typically use
+    // BGRX/BGRA byte order on little-endian systems.
+    // Swap red and blue channels to match the server’s native pixel layout.
+    // Without this conversion, colors appear incorrect.
+    for pixel in pixel_data.chunks_exact_mut(4) {
+        pixel.swap(0, 2); // Swap Red and Blue channels
+    }
+
+    // Create a Graphics Context (GC).
+    // A GC is required by X11 for image uploads, even though most of its
+    // drawing settings are unused when using put_image.
     let gc = conn.generate_id()?;
-    // Associate the GC with the pixmap and configure its foreground color.
-    conn.create_gc(gc, pixmap, &CreateGCAux::new().foreground(color))?;
+    conn.create_gc(gc, pixmap, &CreateGCAux::new())?;
 
-    // Paint a solid-color rectangle onto the pixmap using the GC.
-    // This is only for the solid-color case and will be replaced when using real images.
-    conn.poly_fill_rectangle(
-        pixmap, // BG Image (pixmap)
-        gc,     // The Graphics Context to paint on
-        &[Rectangle {
-            x: 0,
-            y: 0, // Start from top-left corner
+    // Upload the image pixels into the pixmap.
+    // This writes the final wallpaper image into server memory.
+    // No scaling or color conversion happens here; the data must already be correct.
+    conn.put_image(
+        ImageFormat::Z_PIXMAP,
+        pixmap, // drawable: Destination pixmap (wallpaper image)
+        gc,     // Graphics Context (required by X11)
         width,
-            height, // Set rectangle dimensions = screen width, height
-        }],
+        height, // width/height: size of the uploaded image region in pixels
+        0,
+        0,           // dst_x/dst_y: Destination offset inside the pixmap (top-left corner)
+        0,           // left_pad: legacy bitmap padding, always 0 for modern images
+        depth,       // depth: must match the root window’s depth (usually 24 or 32)
+        &pixel_data, // data: raw BGRA/BGRX pixel buffer
     )?;
 
     // Grab and lock the X server to prevent other clients from observing or reacting to intermediate state.
@@ -113,7 +141,7 @@ fn main() -> Result<()> {
     let atom_root = conn.intern_atom(false, b"_XROOTPMAP_ID")?.reply()?.atom;
     let atom_setroot = conn.intern_atom(false, b"_XSETROOT_ID")?.reply()?.atom;
 
-    // Set root window properties that publish the wallpaper pixmap location to consumers.
+    // Set root window properties that publish the wallpaper pixmap location to other clients.
     conn.change_property32(
         PropMode::REPLACE,
         root,