diff --git a/hcl b/hcl
index 001d44d..9dc33a9 160000
--- a/hcl
+++ b/hcl
@@ -1 +1 @@
-Subproject commit 001d44d6b9693a9ad3fd6fc8bc44e8dc22ad7149
+Subproject commit 9dc33a9abadbde8e0c2ffc853a35feaf6990c143
diff --git a/src/main.rs b/src/main.rs
index e569a21..2f8e437 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -25,7 +25,7 @@ mod max6675;
 mod st7735;
 
 use printer::UsartPrinter;
-use st7735::gfx::PrimitveGFX;
+use st7735::gfx::{PrimitveGFX, GFX};
 
 
 fn configure_clocks(rcc: &mut rcc::RCC) {
@@ -128,6 +128,9 @@ fn run(mut scs: scs::Instance, mut p: hcl::platform::Instance) {
         st7735io.fill_rect(4, 64, 76, 60, st7735::COLOR_GREEN);
         st7735io.fill_rect(80, 4, 76, 60, st7735::COLOR_BLUE);
         st7735io.fill_rect(80, 64, 76, 60, st7735::COLOR_YELLOW);
+
+
+        st7735io.draw_line(4, 4, 80, 64, st7735::COLOR_GREEN);
         systick::delay_ms(2000);
     }
     let (st7735, mut spi, mut gpio) = st7735io.done();
diff --git a/src/st7735/gfx.rs b/src/st7735/gfx.rs
index 43c2c5a..c458627 100644
--- a/src/st7735/gfx.rs
+++ b/src/st7735/gfx.rs
@@ -1,30 +1,88 @@
 pub trait PrimitveGFX {
-    type ColorType;
-    type CoordinateType;
-
-
     fn draw_pixel(&mut self,
-                  x: Self::CoordinateType,
-                  y: Self::CoordinateType,
-                  color: Self::ColorType);
+                  x: u8,
+                  y: u8,
+                  color: u16);
 
     fn fill_rect(&mut self,
-                 x: Self::CoordinateType,
-                 y: Self::CoordinateType,
-                 w: Self::CoordinateType,
-                 h: Self::CoordinateType,
-                 color: Self::ColorType);
+                 x: u8,
+                 y: u8,
+                 w: u8,
+                 h: u8,
+                 color: u16);
 
 
     fn draw_fast_vline(&mut self,
-                       x: Self::CoordinateType,
-                       y: Self::CoordinateType,
-                       h: Self::CoordinateType,
-                       color: Self::ColorType);
+                       x: u8,
+                       y: u8,
+                       h: u8,
+                       color: u16);
 
     fn draw_fast_hline(&mut self,
-                       x: Self::CoordinateType,
-                       y: Self::CoordinateType,
-                       w: Self::CoordinateType,
-                       color: Self::ColorType);
+                       x: u8,
+                       y: u8,
+                       w: u8,
+                       color: u16);
+}
+
+
+pub trait GFX : PrimitveGFX {
+    fn draw_line(&mut self, x0 : u8, y0 : u8, x1 : u8, y1 : u8, color : u16) {
+    	let steep_dir_vertical = ((y1 as i16) - (y0 as i16)).abs() > ((x1 as i16) - (x0 as i16)).abs();
+
+
+    	let (x0, y0, x1, y1) = if (steep_dir_vertical) {
+    	    (y0, x0, y1, x1)
+    	}
+        else {
+            (x0, y0, x1, y1)
+        };
+
+    	let (x0, y0, x1, y1) = if (x0 > x1) {
+            (x1, y1, x0, y0)
+    	}
+        else {
+            (x0, y0, x1, y1)
+        };
+
+
+      	let dx = (x1 as i16) - (x0 as i16);
+      	let dy = ((y1 as i16) - (y0 as i16)).abs();
+
+    	let mut err = dx / 2;
+
+    	let y_step : i16 = if (y0 < y1) {
+    		1
+    	} else {
+    		-1
+    	};
+
+
+    	let mut seg = x0;
+        let mut cur_y = y0 as i16;
+    	for cur_x in x0..(x1 + 1) {
+    		err -= dy;
+    		if (err < 0) {
+    			if (steep_dir_vertical) {
+    				self.draw_fast_vline(cur_y as u8, seg, cur_x - seg + 1, color);
+    			} else {
+    				self.draw_fast_hline(seg, cur_y as u8, cur_x - seg + 1, color);
+    			}
+    			cur_y += y_step;
+    			err += dx;
+    			seg = cur_x + 1;
+    		}
+    	}
+
+        // Finish line case there is a piece missing
+        let cur_y = cur_y as u8;
+        let last_len = ((x1 as i16) - (seg as i16) + 1) as u8;
+
+    	if steep_dir_vertical {
+    		self.draw_fast_vline(cur_y, seg, last_len, color);
+    	} else {
+    		self.draw_fast_hline(seg, cur_y, last_len, color);
+    	}
+
+    }
 }
diff --git a/src/st7735/mod.rs b/src/st7735/mod.rs
index 4da2a26..23e987b 100644
--- a/src/st7735/mod.rs
+++ b/src/st7735/mod.rs
@@ -429,11 +429,9 @@ impl<SPIAddr, GPIOAddr> St7735IO<SPIAddr, GPIOAddr>
 impl<SPIAddr, GPIOAddr> gfx::PrimitveGFX for St7735IO<SPIAddr, GPIOAddr>
     where SPIAddr: Location,
             GPIOAddr: Location {
-    type ColorType = u16;
-    type CoordinateType = u8;
 
-    fn draw_pixel(&mut self, x: Self::CoordinateType, y: Self::CoordinateType,
-                  color: Self::ColorType) {
+    fn draw_pixel(&mut self, x: u8, y: u8,
+                  color: u16) {
     	if x >= self.st7735.width || y >= self.st7735.height {
     		return;
     	}
@@ -448,9 +446,9 @@ impl<SPIAddr, GPIOAddr> gfx::PrimitveGFX for St7735IO<SPIAddr, GPIOAddr>
       	self.set_cs();
     }
 
-    fn fill_rect(&mut self, x: Self::CoordinateType, y: Self::CoordinateType,
-                 w: Self::CoordinateType, h: Self::CoordinateType,
-                 color: Self::ColorType) {
+    fn fill_rect(&mut self, x: u8, y: u8,
+                 w: u8, h: u8,
+                 color: u16) {
 
         if x >= self.st7735.width || y >= self.st7735.height {
             return;
@@ -485,19 +483,22 @@ impl<SPIAddr, GPIOAddr> gfx::PrimitveGFX for St7735IO<SPIAddr, GPIOAddr>
     }
 
     fn draw_fast_vline(&mut self,
-                       x: Self::CoordinateType,
-                       y: Self::CoordinateType,
-                       h: Self::CoordinateType,
-                       color: Self::ColorType) {
+                       x: u8,
+                       y: u8,
+                       h: u8,
+                       color: u16) {
         self.fill_rect(x, y, 1, h, color);
     }
 
     fn draw_fast_hline(&mut self,
-                       x: Self::CoordinateType,
-                       y: Self::CoordinateType,
-                       w: Self::CoordinateType,
-                       color: Self::ColorType) {
+                       x: u8,
+                       y: u8,
+                       w: u8,
+                       color: u16) {
         self.fill_rect(x, y, w, 1, color);
     }
-
 }
+
+impl<SPIAddr, GPIOAddr> gfx::GFX for St7735IO<SPIAddr, GPIOAddr>
+    where SPIAddr: Location,
+            GPIOAddr: Location {}