gpu_display: add X11 backend

This change adds an X11 backend to the gpu_display crate. With this
addition, the virtio-gpu device can display to traditional linux
desktops that only have X11 output.

Change-Id: I86c80cac91ca5bdc97588194a44040273ae69385
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1591572
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
Commit-Queue: Zach Reizner <zachr@chromium.org>
Tested-by: Zach Reizner <zachr@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Auto-Submit: Zach Reizner <zachr@chromium.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/gpu_display/examples/simple_open.rs b/gpu_display/examples/simple_open.rs
new file mode 100644
index 0000000..bb7b1a2
--- /dev/null
+++ b/gpu_display/examples/simple_open.rs
@@ -0,0 +1,25 @@
+use gpu_display::GpuDisplay;
+
+fn main() {
+    let mut disp = GpuDisplay::open_x(None::<&str>).unwrap();
+    let surface_id = disp.create_surface(None, 1280, 1024).unwrap();
+
+    let mem = disp.framebuffer(surface_id).unwrap();
+    for y in 0..1024 {
+        let mut row = [0u32; 1280];
+        for x in 0..1280 {
+            let b = ((x as f32 / 1280.0) * 256.0) as u32;
+            let g = ((y as f32 / 1024.0) * 256.0) as u32;
+            row[x] = b | (g << 8);
+        }
+        mem.as_volatile_slice()
+            .offset((1280 * 4 * y) as u64)
+            .unwrap()
+            .copy_from(&row);
+    }
+    disp.flip(surface_id);
+
+    while !disp.close_requested(surface_id) {
+        disp.dispatch_events();
+    }
+}