refactor project structure (start of redoing atomic branch without atomics)

src/widget/rect.rs

@@ -0,0 +1,51 @@
+use crate::prelude::*;
+
+#[derive(Clone, Copy)]
+pub struct Rect {
+    pub color: UiColor,
+    pub radius: f32,
+    pub thickness: f32,
+    pub inner_radius: f32,
+}
+
+impl Rect {
+    pub fn new(color: UiColor) -> Self {
+        Self {
+            color,
+            radius: 0.0,
+            inner_radius: 0.0,
+            thickness: 0.0,
+        }
+    }
+    pub fn color(mut self, color: UiColor) -> Self {
+        self.color = color;
+        self
+    }
+    pub fn radius(mut self, radius: impl UiNum) -> Self {
+        self.radius = radius.to_f32();
+        self
+    }
+}
+
+impl Widget for Rect {
+    fn draw(&mut self, painter: &mut Painter) {
+        painter.primitive(RectPrimitive {
+            color: self.color,
+            radius: self.radius,
+            thickness: self.thickness,
+            inner_radius: self.inner_radius,
+        });
+    }
+
+    fn desired_width(&mut self, _: &mut SizeCtx) -> Len {
+        Len::rest(1)
+    }
+
+    fn desired_height(&mut self, _: &mut SizeCtx) -> Len {
+        Len::rest(1)
+    }
+}
+
+pub fn rect(color: UiColor) -> Rect {
+    Rect::new(color)
+}