First not fully correct filled polygons

@@ -39,6 +39,7 @@ pub trait Canvas<T> {
     fn clear(&mut self);
     fn draw(&mut self, c :&dyn Drawable<T>, ofs :Coordinate<T>, color :u32);
     fn put_text(&self, ofs :Coordinate<T>, s :&str);
+    fn set_pixel(&mut self, c :Coordinate<T>, color :u32);
     fn show(&self);
 }
 
@@ -46,8 +47,10 @@ pub trait Drawable<T> {
     fn plot(&self) -> Coordinates<T>;
 }
 
-pub trait Fillable<T> {
-    fn fill(&self) -> Coordinates<T>;
+pub trait Fillable<T>
+where T: Add<Output = T> + Sub<Output = T> + Div<Output = T>
+       + Debug + Copy + From<i32> {
+    fn fill(&self, canvas :&mut dyn Canvas<T>, color :u32);
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -440,17 +443,12 @@ where T: Add<Output = T> + Sub<Output = T> + Div<Output = T>
 impl<T> Fillable<T> for Polygon<T>
 where T: Add<Output = T> + Sub<Output = T> + Div<Output = T>
        + Debug + Clone + Copy + From<i32> {
-    fn fill(&self) -> Coordinates<T> {
+    fn fill(&self, canvas :&mut dyn Canvas<T>, color :u32) {
         let scanlines = self.left_vertices().zip(self.right_vertices());
 
-        // vertices is an iterator over all vertices making this polygon.
-        let vertices = scanlines.flat_map(|(l, r)| l.line_iter(&r));
-
-        // for debug only…
-        //let vertices :Vec<(Coordinate<T>)> = vertices.collect();
-        //println!("== [{}] {:?}", vertices.len(), vertices);
-
-        Coordinates(Vec::<Coordinate<T>>::new())
+        for l in scanlines.flat_map(|(l, r)| l.line_iter(&r)) {
+            canvas.set_pixel(l, color);
+        }
     }
 }
 

@@ -22,7 +22,7 @@ use std::convert::{From, Into};
 use std::ops::{Add,Sub,Neg,Mul,Div};
 use std::fmt::Debug;
 
-use crate::easel::{Canvas,Coordinate,Coordinates,Polygon,Fillable};
+use crate::easel::{Canvas, Coordinate, Coordinates, Polygon};
 use crate::transform::{TMatrix, Transformable};
 use crate::trigonometry::Trig;
 use crate::vector::Vector;
@@ -361,7 +361,7 @@ where T: Add<Output = T> + Sub<Output = T> + Neg<Output = T>
                                     / (n.mag() * light.dir().mag()),
                        };
 
-                       // this if represents a first simple backface culling
+                       // this "if" represents a first simple backface culling
                        // approach. We only return face that face towards us.
                        if lf < 0.into() {
                            r = r * -lf;
@@ -372,8 +372,6 @@ where T: Add<Output = T> + Sub<Output = T> + Neg<Output = T>
                                       | (g.round() as u32) << 8
                                       | (b.round() as u32);
 
-                           (&pg).fill();
-
                            Some((pg, c))
                        } else {
                            None

@@ -30,14 +30,13 @@ use std::time::{Duration, Instant};
 
 use fractional::continuous::Continuous;
 use fractional::easel::{ Coordinate, Coordinates, Drawable, Line, Polyline
-                       , Polygon};
+                       , Polygon, Canvas, Fillable };
 use fractional::fractional::{Fractional, from_vector};
 use fractional::trigonometry::Trig;
 use fractional::vector::Vector;
 use fractional::transform::{TMatrix, Transformable};
 
 use fractional::xcb::{XcbEasel, XcbCanvas};
-use fractional::easel::Canvas;
 
 use fractional::geometry::{Camera,DirectLight,Polyeder,Primitives};
 
@@ -351,7 +350,9 @@ fn _democanvas<T>( xcb         :&XcbEasel
 
             for (o, color) in objects {
                 for (pg, c) in o.project(&camera, &light, color) {
-                    canvas.draw(&pg, Coordinate(0, 0, 0.into()), c);
+                    //canvas.draw(&pg, Coordinate(0, 0, 0.into()), c);
+                    (&pg).fill(&mut canvas, c);
+                    //println!("\n");
                 }
             }
 

@@ -240,6 +240,14 @@ impl<'a,T> Canvas<T> for XcbCanvas<'a> {
         self.conn.flush();
     }
 
+    fn set_pixel(&mut self, c :Coordinate<T>, color :u32) {
+        let Coordinate(x, y, _) = c;
+        let idx :usize = (y * (self.width as i32) + x) as usize;
+
+        //print!("({}, {})", idx, color);
+        self.shm[idx] = color;
+    }
+
     fn show(&self) {
         xcb::copy_area( &self.conn, self.pixmap, self.window, self.gc
                       , 0, 0, 0, 0