Use structs with Drawable trait instead of methods on shm_pool

src/graphics/circle.rs

@@ -0,0 +1,39 @@
+use crate::wayland::shm::ShmPool;
+use super::drawable::{Drawable, color_blend};
+
+// x and y are center of circle
+pub struct Circle {
+    x: usize,
+    y: usize,
+    radius: usize,
+    color: u32,
+}
+
+impl Circle {
+    pub fn new(x: usize, y: usize, radius: usize, color: u32) -> Self {
+        Circle { x, y, radius, color }
+    }
+}
+
+impl Drawable for Circle {
+    fn draw(&self, shm_pool: &mut ShmPool) {
+        for l_row in 1..self.radius { 
+            let inner_diff = (((self.radius-1).pow(2) - l_row.pow(2)) as f64).sqrt();
+            let outer_diff = ((self.radius.pow(2) - l_row.pow(2)) as f64).sqrt();
+            let row: Vec<u32> = vec![self.color; 2*(inner_diff.floor() as usize)];
+            shm_pool.write(&row, (self.y-l_row)*shm_pool.width + self.x - inner_diff.floor() as usize);
+            shm_pool.write(&row, (self.y+l_row-1)*shm_pool.width + self.x - inner_diff.floor() as usize);
+            for l_col in (inner_diff.floor() as usize+1)..(outer_diff.ceil() as usize) {
+                let distance = ((l_row.pow(2) + l_col.pow(2)) as f64).sqrt();
+                let offset = (self.y-l_row)*shm_pool.width + self.x - l_col;
+                shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset), distance.fract()), offset as isize);
+                let offset = (self.y-l_row)*shm_pool.width + self.x + l_col-1;
+                shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset), distance.fract()), offset as isize);
+                let offset = (self.y+l_row-1)*shm_pool.width + self.x - l_col;
+                shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset), distance.fract()), offset as isize);
+                let offset = (self.y+l_row-1)*shm_pool.width + self.x + l_col-1;
+                shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset), distance.fract()), offset as isize);
+            }
+        }
+    }
+}