userlib now implements embedded_graphics::DrawTarget

Cargo.lock

@@ -15,6 +15,15 @@ dependencies = [
 [[package]]
 name = "abi"
 version = "0.1.0"
+dependencies = [
+ "abi_sys",
+ "embedded-graphics",
+ "shared",
+]
+
+[[package]]
+name = "abi_sys"
+version = "0.1.0"
 dependencies = [
  "embedded-graphics",
  "shared",
@@ -208,6 +217,7 @@ name = "calculator"
 version = "0.1.0"
 dependencies = [
  "abi",
+ "embedded-graphics",
 ]
 
 [[package]]
@@ -1163,7 +1173,7 @@ dependencies = [
 name = "kernel"
 version = "0.1.0"
 dependencies = [
- "abi",
+ "abi_sys",
  "bitflags 2.9.1",
  "bt-hci",
  "cortex-m",

abi/Cargo.toml

@@ -6,3 +6,4 @@ edition = "2024"
 [dependencies]
 embedded-graphics = "0.8.1"
 shared = { path = "../shared" }
+abi_sys = { path = "../abi_sys" }

abi/src/lib.rs

@@ -1,28 +1,76 @@
 #![no_std]
 
-pub use embedded_graphics::{
+use abi_sys::{Syscall, call_abi};
-    Pixel,
-    geometry::Point,
-    pixelcolor::{Rgb565, RgbColor},
-};
 use shared::keyboard::{KeyCode, KeyEvent, KeyState, Modifiers};
 
-// Instead of extern, declare a static pointer in a dedicated section
+pub mod display {
-#[unsafe(no_mangle)]
+    use crate::{Syscall, call_abi};
-#[unsafe(link_section = ".user_reloc")]
+    use embedded_graphics::{
-#[allow(non_upper_case_globals)]
+        Pixel,
-pub static mut call_abi_ptr: usize = 0;
+        geometry::{Dimensions, Point},
+        pixelcolor::{Rgb565, RgbColor},
+        prelude::{DrawTarget, Size},
+        primitives::Rectangle,
+    };
 
-// Helper to call it
+    pub const SCREEN_WIDTH: usize = 320;
-pub unsafe fn call_abi(call: *const Syscall) {
+    pub const SCREEN_HEIGHT: usize = 320;
-    let f: extern "C" fn(*const Syscall) = unsafe { core::mem::transmute(call_abi_ptr) };
-    f(call);
-}
 
-#[repr(C)]
+    pub type Pixel565 = Pixel<Rgb565>;
-pub enum Syscall {
+
-    DrawIter {
+    pub struct Display;
-        pixels: *const Pixel<Rgb565>,
+
-        len: usize,
+    impl Display {
-    },
+        fn syscall_draw(&self, pixels: &[Pixel565]) {
+            let syscall = Syscall::DrawIter {
+                pixels: pixels.as_ptr(),
+                len: pixels.len(),
+            };
+            unsafe {
+                call_abi(&syscall);
+            }
+        }
+    }
+
+    impl Dimensions for Display {
+        fn bounding_box(&self) -> Rectangle {
+            Rectangle {
+                top_left: Point { x: 0, y: 0 },
+                size: Size {
+                    width: SCREEN_WIDTH as u32,
+                    height: SCREEN_HEIGHT as u32,
+                },
+            }
+        }
+    }
+
+    impl DrawTarget for Display {
+        type Color = Rgb565;
+        type Error = ();
+
+        fn draw_iter<I>(&mut self, pixels: I) -> Result<(), Self::Error>
+        where
+            I: IntoIterator<Item = Pixel<Self::Color>>,
+        {
+            const BUF_SIZE: usize = 1024; // tune this for performance
+            let mut buf: [Pixel565; BUF_SIZE] = [Pixel(Point::new(0, 0), Rgb565::BLACK); BUF_SIZE];
+
+            let mut count = 0;
+            for p in pixels {
+                buf[count] = p;
+                count += 1;
+
+                if count == BUF_SIZE {
+                    self.syscall_draw(&buf[..count]);
+                    count = 0;
+                }
+            }
+
+            if count > 0 {
+                self.syscall_draw(&buf[..count]);
+            }
+
+            Ok(())
+        }
+    }
 }

abi_sys/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "abi_sys"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+embedded-graphics = "0.8.1"
+shared = { path = "../shared" }

abi_sys/src/lib.rs

@@ -0,0 +1,28 @@
+#![no_std]
+
+pub use embedded_graphics::{
+    Pixel,
+    geometry::Point,
+    pixelcolor::{Rgb565, RgbColor},
+};
+use shared::keyboard::{KeyCode, KeyEvent, KeyState, Modifiers};
+
+// Instead of extern, declare a static pointer in a dedicated section
+#[unsafe(no_mangle)]
+#[unsafe(link_section = ".user_reloc")]
+#[allow(non_upper_case_globals)]
+pub static mut call_abi_ptr: usize = 0;
+
+// Helper to call it
+pub unsafe fn call_abi(call: *const Syscall) {
+    let f: extern "C" fn(*const Syscall) = unsafe { core::mem::transmute(call_abi_ptr) };
+    f(call);
+}
+
+#[repr(C)]
+pub enum Syscall {
+    DrawIter {
+        pixels: *const Pixel<Rgb565>,
+        len: usize,
+    },
+}

kernel/Cargo.toml

@@ -87,4 +87,4 @@ talc = "4.4.3"
 spin = "0.10.0"
 
 shared = { path = "../shared" }
-abi = { path = "../abi" }
+abi_sys = { path = "../abi_sys" }

kernel/src/abi.rs

@@ -1,4 +1,4 @@
-use abi::Syscall;
+use abi_sys::Syscall;
 use defmt::info;
 use embassy_futures::block_on;
 use embedded_graphics::{

user-apps/calculator/Cargo.toml

@@ -5,3 +5,4 @@ edition = "2024"
 
 [dependencies]
 abi = { path = "../../abi" }
+embedded-graphics = "0.8.1"

user-apps/calculator/src/main.rs

@@ -1,8 +1,16 @@
 #![no_std]
 #![no_main]
 
-use abi::{Pixel, Point, Rgb565, RgbColor, Syscall, call_abi};
+use abi::display::Display;
 use core::panic::PanicInfo;
+use embedded_graphics::{
+    Drawable,
+    geometry::{Dimensions, Point},
+    mono_font::{MonoTextStyle, ascii::FONT_6X10},
+    pixelcolor::Rgb565,
+    prelude::RgbColor,
+    text::{Alignment, Text},
+};
 
 #[panic_handler]
 fn panic(_info: &PanicInfo) -> ! {
@@ -11,23 +19,18 @@ fn panic(_info: &PanicInfo) -> ! {
 
 #[unsafe(no_mangle)]
 pub extern "C" fn _start() {
-    // Local pixel buffer
+    let mut display = Display;
-    let mut pixels = [Pixel(Point { x: 50, y: 50 }, Rgb565::RED); 300];
-    for (i, p) in pixels.iter_mut().enumerate() {
-        *p = Pixel(
-            Point {
-                x: i as i32,
-                y: i as i32,
-            },
-            Rgb565::RED,
-        )
-    }
 
-    // Construct syscall with raw pointer + length
+    let character_style = MonoTextStyle::new(&FONT_6X10, Rgb565::RED);
-    let call = Syscall::DrawIter {
-        pixels: pixels.as_ptr(), // raw pointer
-        len: pixels.len(),       // number of elements
-    };
 
-    unsafe { call_abi(&call) };
+    // Draw centered text.
+    let text = "embedded-graphics";
+    Text::with_alignment(
+        text,
+        display.bounding_box().center() + Point::new(0, 15),
+        character_style,
+        Alignment::Center,
+    )
+    .draw(&mut display)
+    .unwrap();
 }