diff --git a/README.md b/README.md
index d141ecf..69414da 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,5 @@
+[![Build status](https://travis-ci.org/caemor/eink-waveshare-rs.svg?branch=master)](https://travis-ci.org/caemor/eink-waveshare-rs)
+
 # eink-waveshare-rs
 IN WORK! Drivers for various EPDs from Waveshare. Currently only support for the 4.2 Black/White one
 
@@ -10,10 +12,10 @@ Due to a broken
 
 - [ ] add some basic buffer drawing abilities
 - [ ] test Embedded Linux (rpi) example
-- [ ] test f3 example
+- [ ] add f3 example
 - [ ] improve the partial drawing/check the timings/timing improvements/....
-- [ ] for later: add support or the smaller waveshare epds
-- [ ] License: Stay with ISC (=MIT) or go to Apache+MIT Dual Version as used in many other projects
+- [ ] for later: add support for the smaller waveshare epds
+- [ ] License: Stay with ISC (=MIT) or go to Apache+MIT Dual Version as used in many other projects?
 
 
 ## Drawing
@@ -33,5 +35,3 @@ There are some examples in the examples folder.
 
 The f3 example is broken/working on a old version
 
-
-## Documenation
diff --git a/src/drawing/mod.rs b/src/drawing/mod.rs
index 11f546b..4c7e1af 100644
--- a/src/drawing/mod.rs
+++ b/src/drawing/mod.rs
@@ -1,4 +1,6 @@
 
+
+
 #[derive(Clone, Copy)]
 pub enum Displayorientation {
     /// No rotation
@@ -10,22 +12,22 @@ pub enum Displayorientation {
     /// Rotate 270 degrees clockwise
     Rotate270,
 }
-/*
+
 //WARNING: Adapt for bigger sized displays!
-pub struct Display_Description {
+pub struct DisplayDescription {
     width: u16,
     height: u16,
-    buffer_size: u16,
+    buffer_size: u16
 }
 
-impl Display_Description {
-    pub fn new(width: u16, height: u16, buffer_size: u16) -> Display_Description {
+// impl Display_Description {
+//     pub fn new(width: u16, height: u16, buffer_size: u16) -> Display_Description {
 
-    }
-}
+//     }
+// }
 
 pub enum Display {
-    Eink_42_BW,
+    Eink42BlackWhite,
 }
 
 impl Display {
@@ -35,7 +37,7 @@ impl Display {
     /// - Neccessary Buffersize
     pub fn get_dimensions(&self) -> (u16, u16, u16) {
         match self {
-            Display::Eink_42_BW => (400, 300, 15000)
+            Display::Eink42BlackWhite => (400, 300, 15000)
         }
     }
 }
@@ -43,8 +45,29 @@ impl Display {
 pub struct Graphics {
     width: u16,
     height: u16,
-    rotate: Displayorientation,
-    buffer: [u8; 15000],   
+    rotation: Displayorientation,
+    //buffer: Box<u8>//[u8; 15000],   
+}
+
+pub enum Color {
+    Black,
+    White
+}
+
+impl Color {
+    fn get_color_value(&self) -> u8 {
+        match self {
+            Color::White => 0u8,
+            Color::Black => 1u8,            
+        }
+    }
+
+    fn get_full_byte_color(&self) -> u8 {
+        match self {
+            Color::White => 0u8,
+            Color::Black => 0xff,
+        }
+    } 
 }
 
 
@@ -52,10 +75,353 @@ pub struct Graphics {
 impl Graphics {
     /// width needs to be a multiple of 8!
     pub fn new(width: u16, height: u16) -> Graphics{
-        Graphics {width, height, rotate: Displayorientation::Rotate0}
+        Graphics {width, height, rotation: Displayorientation::Rotate0}
     }
 
-    pub fn clear(&mut self) {
-        self.buffer = &mut [0u8; 1000]
+    pub fn clear(&mut self, buffer: &mut[u8], color: &Color) {
+        for elem in buffer.iter_mut() {
+            *elem = color.get_full_byte_color();
+        }
+    }
+
+    pub fn draw_pixel(&self, buffer: &mut[u8], x: u16, y: u16, color: &Color) {
+        let (idx, bit) = match self.rotation {
+            Displayorientation::Rotate0 | Displayorientation::Rotate180 
+                => ((x + self.width * y) / 8,
+                    0x80 >> (x % 8)),
+            Displayorientation::Rotate90 | Displayorientation::Rotate270
+                => (y / 8 * self.width + x,
+                    0x80 >> (y % 8)),
+        };
+
+        if idx >= buffer.len() as u16 {
+            return;
+        }
+
+        match color {
+            Color::White => {
+                buffer[idx as usize] &= !bit; 
+            },
+            Color::Black => {
+                buffer[idx as usize] |= bit;
+            }
+        }
     }
-}*/
\ No newline at end of file
+
+    pub fn draw_char(&self, buffer: &mut[u8]) {
+        unimplemented!(); 
+    }
+
+    pub fn draw_string(&self, buffer: &mut[u8]) {
+        unimplemented!(); 
+    }
+
+//     void plotLine(int x0, int y0, int x1, int y1)
+// {
+//    int dx =  abs(x1-x0), sx = x0<x1 ? 1 : -1;
+//    int dy = -abs(y1-y0), sy = y0<y1 ? 1 : -1; 
+//    int err = dx+dy, e2; /* error value e_xy */
+ 
+//    for(;;){  /* loop */
+//       setPixel(x0,y0);
+//       if (x0==x1 && y0==y1) break;
+//       e2 = 2*err;
+//       if (e2 >= dy) { err += dy; x0 += sx; } /* e_xy+e_x > 0 */
+//       if (e2 <= dx) { err += dx; y0 += sy; } /* e_xy+e_y < 0 */
+//    }
+// }
+    //bresenham algorithm for lines
+    pub fn draw_line(&self, buffer: &mut[u8], x0: u16, y0: u16, x1: u16, y1: u16, color: &Color) {
+        let mut x0 = x0 as i16;
+        let x1 = x1 as i16;
+        let mut y0 = y0 as i16;
+        let y1 = y1 as i16;
+
+        let dx = i16::abs(x1 - x0);
+        let sx = if x0 < x1 { 1 } else { -1 };
+
+        let dy = - i16::abs(y1 - y0);
+        let sy = if y0 < y1 { 1 } else { -1 };
+        
+        let mut err = dx + dy;
+
+        loop {
+            self.draw_pixel(buffer, x0 as u16, y0 as u16, color);
+
+            if x0 == x1 && y0 == y1 {
+                break;
+            }
+
+            let e2 = 2*err;
+
+            if e2 >= dy {
+                err += dy;
+                x0 += sx;
+            }
+
+            if e2 <= dx {
+                err += dx;
+                y0 += sy;
+            }
+        }
+    }
+
+    /// TODO: maybe optimize by grouping up the bytes? But is it worth the longer and more complicated function? is it even faster?
+    pub fn draw_horizontal_line(&self, buffer: &mut[u8], x: u16, y: u16, length: u16, color: &Color) {
+        for i in 0..length {
+            self.draw_pixel(buffer, x + i, y, color);
+        }
+    }
+
+    ///
+    pub fn draw_vertical_line(&self, buffer: &mut[u8], x: u16, y: u16, length: u16, color: &Color) {
+        for i in 0..length {
+            self.draw_pixel(buffer, x, y + i, color);
+        }
+    }
+
+    pub fn draw_rectangle(&self, buffer: &mut[u8], x0: u16, y0: u16, x1: u16, y1: u16, color: &Color) {
+        let (min_x, max_x) = if x0 <= x1 { (x0, x1) } else { (x1, x0) };
+        let (min_y, max_y) = if y0 <= y1 { (y0, y1) } else { (y1, y0) };
+        let x_len = max_x - min_x;
+        let y_len = max_y - min_y;
+        self.draw_horizontal_line(buffer, min_x, min_y, x_len, color);
+        self.draw_horizontal_line(buffer, min_x, max_y, x_len, color);
+        self.draw_vertical_line(buffer, min_x, min_y, y_len, color);
+        self.draw_vertical_line(buffer, max_x, min_y, y_len, color);
+    }
+
+    pub fn draw_filled_rectangle(&self, buffer: &mut[u8], x0: u16, y0: u16, x1: u16, y1: u16, color: &Color) {
+        let (min_x, max_x) = if x0 <= x1 { (x0, x1) } else { (x1, x0) };
+        let (min_y, max_y) = if y0 <= y1 { (y0, y1) } else { (y1, y0) };
+        let x_len = max_x - min_x;
+        let y_len = max_y - min_y;
+        for i in 0..y_len {
+            self.draw_horizontal_line(buffer, min_x, min_y + i, x_len, color);
+        }
+    }
+
+    fn draw_pixel_helper(&self, buffer: &mut[u8], x: i16, y: i16, color: &Color) {
+        if x >= 0 && y >= 0 {
+            self.draw_pixel(buffer, x as u16, y as u16, color);
+        }
+    }
+
+    //TODO: test if circle looks good
+    pub fn draw_circle(&self, buffer: &mut[u8], x: u16, y: u16, radius: u16, color: &Color) {
+        let radius = radius as i16;
+        let x_mid = x as i16;
+        let y_mid = y as i16;
+        let mut x_pos: i16 = 0 - radius; 
+        let mut y_pos = 0;
+        let mut err: i16 = 2 - 2 * radius;
+
+        loop {
+            self.draw_pixel_helper(buffer, x_mid - x_pos, y_mid + y_pos, color);
+            self.draw_pixel_helper(buffer, x_mid - y_pos, y_mid - x_pos, color);
+            self.draw_pixel_helper(buffer, x_mid + x_pos, y_mid - y_pos, color);
+            self.draw_pixel_helper(buffer, x_mid + y_pos, y_mid + x_pos, color);
+
+            let radius = err;
+
+            if radius <= y_pos {
+                y_pos += 1;
+                err += y_pos*2 + 1;
+            }
+
+            if radius > x_pos || err > y_pos {
+                x_pos += 1;
+                err += x_pos*2 + 1;
+            }
+
+            if x_pos >= 0 {
+                break;
+            }
+        }
+    }
+//         }
+//         unimplemented!(); 
+
+
+//         void plotCircle(int xm, int ym, int r)
+// {
+//    int x = -r, y = 0, err = 2-2*r; /* II. Quadrant */ 
+//    do {
+//       setPixel(xm-x, ym+y); /*   I. Quadrant */
+//       setPixel(xm-y, ym-x); /*  II. Quadrant */
+//       setPixel(xm+x, ym-y); /* III. Quadrant */
+//       setPixel(xm+y, ym+x); /*  IV. Quadrant */
+//       r = err;
+//       if (r <= y) err += ++y*2+1;           /* e_xy+e_y < 0 */
+//       if (r > x || err > y) err += ++x*2+1; /* e_xy+e_x > 0 or no 2nd y-step */
+//    } while (x < 0);
+// }
+//     }
+
+    pub fn draw_filled_circle(&self, buffer: &mut[u8]) {
+        unimplemented!(); 
+    }
+
+    pub fn send_multiple_data(&mut self, data: &mut[u8]) {
+        data[0] = 1;
+        let i = data.len() as u8;
+        data[1] = i;
+    }
+}
+
+
+
+#[cfg(test)]
+mod graphics {
+    use super::*;
+
+    #[test]
+    fn test_filled_rectangle() {
+        let mut buffer = [0u8; 150];
+        let graphics = Graphics::new(40, 30);
+        graphics.draw_filled_rectangle(&mut buffer, 0, 0, 40, 30, &Color::Black);
+        
+        assert_eq!(buffer[0], 0xff);
+
+        for &elem in buffer.iter() {
+            
+            assert_eq!(elem, 0xffu8);
+        }
+
+        
+    }
+
+    /// draw a 4x4 in the top left corner
+    #[test]
+    fn test_filled_rectangle2() {
+        let mut buffer = [0u8; 8];
+        let graphics = Graphics::new(8, 8);
+        graphics.draw_filled_rectangle(&mut buffer, 0, 0, 4, 4, &Color::Black);
+        
+        assert_eq!(buffer[0], 0xf0);
+
+        let mut counter = 0;
+        for &elem in buffer.iter() {
+            counter += 1;           
+
+            if counter <= 4 {
+                assert_eq!(elem, 0xf0);
+            } else {
+                assert_eq!(elem, 0x00);
+            }
+        }
+
+        
+    }
+
+    #[test]
+    fn test_horizontal_line() {
+        let mut buffer = [0u8; 4];
+        let graphics = Graphics::new(16, 2);
+        graphics.draw_horizontal_line(&mut buffer, 1, 0, 14, &Color::Black);
+        
+        assert_eq!(buffer[0], 0x7f);
+        assert_eq!(buffer[1], 0xfe);
+        assert_eq!(buffer[2], 0x00);
+        assert_eq!(buffer[3], 0x00);
+    }
+
+    #[test]
+    fn test_vertical_line() {
+        let mut buffer = [0u8; 8];
+        let graphics = Graphics::new(8, 8);
+        graphics.draw_vertical_line(&mut buffer, 0, 0, 8, &Color::Black);
+
+        graphics.draw_vertical_line(&mut buffer, 5, 0, 8, &Color::Black);
+        
+        
+        assert_eq!(buffer[0], 0x84);
+
+        for &elem in buffer.iter() {
+            
+            assert_eq!(elem, 0x84u8);
+        }
+    }
+
+    //test draw_line for compatibility with draw_vertical_line
+    #[test]
+    fn draw_line_1() {
+        let mut buffer = [0u8; 8];
+        let graphics = Graphics::new(8, 8);
+
+        graphics.draw_vertical_line(&mut buffer, 5, 0, 8, &Color::Black);
+
+        let mut buffer2 = [0u8; 8];
+        let graphics2 = Graphics::new(8, 8);
+
+        graphics2.draw_line(&mut buffer2, 5, 0, 5, 8, &Color::Black);       
+
+        for i in 0..buffer.len() {            
+            assert_eq!(buffer[i], buffer2[i]);
+        }
+    }
+
+    //test draw_line for compatibility with draw_horizontal_line
+    #[test]
+    fn draw_line_2() {
+        let mut buffer = [0u8; 4];
+        let graphics = Graphics::new(16, 2);
+        graphics.draw_horizontal_line(&mut buffer, 1, 0, 14, &Color::Black);
+
+        let mut buffer2 = [0u8; 4];
+        let graphics2 = Graphics::new(16, 2);
+        graphics2.draw_line(&mut buffer2, 1, 0, 14, 0, &Color::Black);       
+
+        for i in 0..buffer.len() {            
+            assert_eq!(buffer[i], buffer2[i]);
+        }
+    }
+
+    //test draw_line for diago
+    #[test]
+    fn draw_line_3() {
+        let mut buffer = [0u8; 8];
+        let graphics = Graphics::new(8, 8);
+
+        graphics.draw_line(&mut buffer, 0, 0, 16, 16, &Color::Black);       
+
+        for i in 0..buffer.len() {            
+            assert_eq!(buffer[i], 0x80 >> i % 8);
+        }
+    }
+
+
+
+    #[test]
+    fn test_pixel() {
+        let mut buffer = [0u8; 8];
+        let graphics = Graphics::new(8, 8);
+        graphics.draw_pixel(&mut buffer, 1, 0, &Color::Black);
+
+        assert_eq!(buffer[0], 0x40);
+
+
+        let mut buffer = [0u8; 16];
+        let graphics = Graphics::new(16, 8);
+        graphics.draw_pixel(&mut buffer, 9, 0, &Color::Black);
+        assert_eq!(buffer[0], 0x00);
+        assert_eq!(buffer[1], 0x40);
+        
+        for &elem in buffer.iter() {
+            
+            //assert_eq!(elem, 0x00u8);
+        }
+    }
+
+    // #[test]
+    // #[should_panic]
+    // fn test_any_panic() {
+    //     divide_non_zero_result(1, 0);
+    // }
+
+    // #[test]
+    // #[should_panic(expected = "Divide result is zero")]
+    // fn test_specific_panic() {
+    //     divide_non_zero_result(1, 10);
+    // }
+}
\ No newline at end of file