Add display demo in main

nucleus/src/main.rs

@@ -41,6 +41,11 @@ mod sync;
 mod tests;
 mod write_to;
 
+use crate::platform::rpi3::{
+    display::{Color, DrawError},
+    vc::VC,
+};
+
 entry!(kmain);
 
 /// The global console. Output of the kernel print! and println! macros goes here.
@@ -154,10 +159,46 @@ pub fn kmain() -> ! {
     #[cfg(test)]
     test_main();
 
+    check_display_init();
+
     println!("Bye, hanging forever...");
     endless_sleep()
 }
 
+fn check_display_init() {
+    display_graphics()
+        .map_err(|e| {
+            println!("Error in display: {}", e);
+        })
+        .ok();
+}
+
+fn display_graphics() -> Result<(), DrawError> {
+    if let Ok(mut display) = VC::init_fb(800, 600, 32) {
+        println!("Display created");
+
+        display.clear(Color::black());
+        println!("Display cleared");
+
+        display.rect(10, 10, 250, 250, Color::rgb(32, 96, 64));
+        display.draw_text(50, 50, "Hello there!", Color::rgb(128, 192, 255))?;
+
+        let mut buf = [0u8; 64];
+        let s = write_to::show(&mut buf, format_args!("Display width {}", display.width));
+
+        if s.is_err() {
+            display.draw_text(50, 150, "Error displaying", Color::red())?
+        } else {
+            display.draw_text(50, 150, s.unwrap(), Color::white())?
+        }
+
+        display.draw_text(150, 50, "RED", Color::red())?;
+        display.draw_text(160, 60, "GREEN", Color::green())?;
+        display.draw_text(170, 70, "BLUE", Color::blue())?;
+    }
+    Ok(())
+}
+
 #[cfg(test)]
 mod main_tests {
     use super::*;