diff --git a/gfxlcd/drawing/area.py b/gfxlcd/drawing/area.py
index 418a84b..9e844c4 100644
--- a/gfxlcd/drawing/area.py
+++ b/gfxlcd/drawing/area.py
@@ -32,47 +32,79 @@ class Area(Pixel):
         for _ in itertools.repeat(None, length):
             self.driver.data(color, None)
 
+    # def _calculate_steps(self, length, step, required_length):
+    #     """calculate lineparts - helper"""
+    #     steps = [length for _ in range(0, step)]
+    #     if step * length < required_length:
+    #         for idx in range(0, required_length - step * length):
+    #             steps[idx] += 1
+    #
+    #     return steps
+
     def _calculate_steps(self, length, step, required_length):
         """calculate lineparts - helper"""
         steps = [length for _ in range(0, step)]
         if step * length < required_length:
-            for idx in range(0, required_length - step * length):
-                steps[idx] += 1
+            offset = len(steps) // 2
+            rest = required_length - step * length
+            steps_even = True if len(steps) & 1 == 0 else False
+            rest_even = True if rest & 1 == 0 else False
+            appendix = 0
+            for idx in range(0, rest):
+                steps[offset + appendix] += 1
+                if steps_even:
+                    appendix = self._calculate_appendix(appendix)
+                elif idx > 0 and rest_even:
+                    appendix = self._calculate_appendix(appendix)
+                elif not rest_even:
+                    appendix = self._calculate_appendix(appendix)
 
         return steps
 
+    def _calculate_appendix(self, appendix):
+        """calculate appendix during drawing a line"""
+        if appendix == 0:
+            appendix = -1
+        elif appendix < 0:
+            appendix *= -1
+        else:
+            appendix = (appendix + 1) * -1
+
+        return appendix
+
     def draw_line(self, pos_x1, pos_y1, pos_x2, pos_y2):
         """draw diagonal line"""
         width = abs(pos_x2 - pos_x1)
         height = abs(pos_y2 - pos_y1)
         if pos_x1 == pos_x2:
-            steps = [height]
+            steps = [height+1]
             horizontal = False
             offset_x = offset_y = 0
         elif pos_y1 == pos_y2:
-            steps = [width]
+            steps = [width+1]
             horizontal = True
             offset_x = offset_y = 0
         elif width > height:
+            width += 1
             if pos_x2 < pos_x1:
                 pos_x1, pos_x2 = pos_x2, pos_x1
                 pos_y1, pos_y2 = pos_y2, pos_y1
             offset_y = 1 if pos_y2 > pos_y1 else -1
             offset_x = 1 if pos_x2 > pos_x1 else -1
             horizontal = True
-            step = height
-            length = width / step
+            step = height + 1
+            length = width // step
             steps = self._calculate_steps(length, step, width)
-
         else:
+            height += 1
             if pos_y2 < pos_y1:
                 pos_x1, pos_x2 = pos_x2, pos_x1
                 pos_y1, pos_y2 = pos_y2, pos_y1
             offset_y = 1 if pos_y2 > pos_y1 else -1
             offset_x = 1 if pos_x2 > pos_x1 else -1
             horizontal = False
-            step = width
-            length = height / step
+            step = width + 1
+            length = height // step
             steps = self._calculate_steps(length, step, height)
 
         delta_y = 0
diff --git a/gfxlcd/tests/test_area_drawing.py b/gfxlcd/tests/test_area_drawing.py
index 1b6a59b..bb3fc00 100644
--- a/gfxlcd/tests/test_area_drawing.py
+++ b/gfxlcd/tests/test_area_drawing.py
@@ -26,3 +26,165 @@ class TestPageDrawing(object):
         buffer = self.get_buffer()
         buffer[1][1] = 1
         assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_two_pixel(self):
+        self.lcd.draw_pixel(1, 1)
+        self.lcd.draw_pixel(2, 2)
+        buffer = self.get_buffer()
+        buffer[1][1] = 1
+        buffer[2][2] = 1
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_horizontal_line(self):
+        self.lcd.draw_line(1, 1, 8, 1)
+        buffer = self.get_buffer()
+        buffer[1][1] = 1
+        buffer[2][1] = 1
+        buffer[3][1] = 1
+        buffer[4][1] = 1
+        buffer[5][1] = 1
+        buffer[6][1] = 1
+        buffer[7][1] = 1
+        buffer[8][1] = 1
+        self.draw_buffer(self.drv.buffer)
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_vertical_line(self):
+        self.lcd.draw_line(1, 1, 1, 14)
+        buffer = self.get_buffer()
+        buffer[1][1] = 1
+        buffer[1][2] = 1
+        buffer[1][3] = 1
+        buffer[1][4] = 1
+        buffer[1][5] = 1
+        buffer[1][6] = 1
+        buffer[1][7] = 1
+        buffer[1][8] = 1
+        buffer[1][9] = 1
+        buffer[1][10] = 1
+        buffer[1][11] = 1
+        buffer[1][12] = 1
+        buffer[1][13] = 1
+        buffer[1][14] = 1
+        self.draw_buffer(self.drv.buffer)
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_overlapping_lines(self):
+        self.lcd.draw_line(1, 1, 8, 1)
+        self.lcd.draw_line(1, 1, 1, 14)
+        buffer = self.get_buffer()
+        buffer[1][1] = 1
+        buffer[2][1] = 1
+        buffer[3][1] = 1
+        buffer[4][1] = 1
+        buffer[5][1] = 1
+        buffer[6][1] = 1
+        buffer[7][1] = 1
+        buffer[8][1] = 1
+        buffer[1][1] = 1
+        buffer[1][2] = 1
+        buffer[1][3] = 1
+        buffer[1][4] = 1
+        buffer[1][5] = 1
+        buffer[1][6] = 1
+        buffer[1][7] = 1
+        buffer[1][8] = 1
+        buffer[1][9] = 1
+        buffer[1][10] = 1
+        buffer[1][11] = 1
+        buffer[1][12] = 1
+        buffer[1][13] = 1
+        buffer[1][14] = 1
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_diagonal_line(self):
+        self.lcd.draw_line(0, 0, 9, 1)
+        buffer = self.get_buffer()
+        buffer[0][0] = 1
+        buffer[1][0] = 1
+        buffer[2][0] = 1
+        buffer[3][0] = 1
+        buffer[4][0] = 1
+        buffer[5][1] = 1
+        buffer[6][1] = 1
+        buffer[7][1] = 1
+        buffer[8][1] = 1
+        buffer[9][1] = 1
+        self.draw_buffer(self.drv.buffer)
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_diagonal_line_even_steps(self):
+        self.lcd.draw_line(0, 0, 9, 15)
+        buffer = self.get_buffer()
+        buffer[0][0] = 1
+        buffer[1][1] = 1
+        buffer[2][2] = 1
+        buffer[2][3] = 1
+        buffer[3][4] = 1
+        buffer[3][5] = 1
+        buffer[4][6] = 1
+        buffer[4][7] = 1
+        buffer[5][8] = 1
+        buffer[5][9] = 1
+        buffer[6][10] = 1
+        buffer[6][11] = 1
+        buffer[7][12] = 1
+        buffer[7][13] = 1
+        buffer[8][14] = 1
+        buffer[9][15] = 1
+        self.draw_buffer(self.drv.buffer)
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_diagonal_line_even_steps_even_rest(self):
+        self.lcd.draw_line(0, 0, 9, 5)
+        buffer = self.get_buffer()
+        buffer[0][0] = 1
+        buffer[1][1] = 1
+        buffer[2][1] = 1
+        buffer[3][2] = 1
+        buffer[4][2] = 1
+        buffer[5][3] = 1
+        buffer[6][3] = 1
+        buffer[7][4] = 1
+        buffer[8][4] = 1
+        buffer[9][5] = 1
+        self.draw_buffer(self.drv.buffer)
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_diagonal_line_odd_steps_even_rest(self):
+        self.lcd.draw_line(0, 0, 9, 6)
+        buffer = self.get_buffer()
+        buffer[0][0] = 1
+        buffer[1][1] = 1
+        buffer[2][2] = 1
+        buffer[3][2] = 1
+        buffer[4][3] = 1
+        buffer[5][3] = 1
+        buffer[6][4] = 1
+        buffer[7][4] = 1
+        buffer[8][5] = 1
+        buffer[9][6] = 1
+        self.draw_buffer(self.drv.buffer)
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_diagonal_line_even_steps_odd_rest(self):
+        self.lcd.draw_line(0, 0, 8, 6)
+        buffer = self.get_buffer()
+        buffer[0][0] = 1
+        buffer[1][1] = 1
+        buffer[2][2] = 1
+        buffer[3][3] = 1
+        buffer[4][3] = 1
+        buffer[5][3] = 1
+        buffer[6][4] = 1
+        buffer[7][5] = 1
+        buffer[8][6] = 1
+        self.draw_buffer(self.drv.buffer)
+        assert_equal(self.drv.buffer, buffer)
+
+    def draw_buffer(self, buffer):
+        for y in range(self.lcd.height):
+            row = ""
+            for x in range(self.lcd.width):
+                row += str(buffer[x][y])
+            print (row)
diff --git a/gfxlcd/tests/test_page_drawing.py b/gfxlcd/tests/test_page_drawing.py
index b937977..2358cf2 100644
--- a/gfxlcd/tests/test_page_drawing.py
+++ b/gfxlcd/tests/test_page_drawing.py
@@ -139,19 +139,18 @@ class TestPageDrawing(object):
         assert_equal(self.lcd.buffer, buffer)
 
     def test_draw_diagonal_line_even_steps_odd_rest(self):
-        self.lcd.draw_line(0, 0, 9, 6)
+        self.lcd.draw_line(0, 0, 8, 6)
         buffer = self.get_buffer()
         buffer[0][0] = 1
         buffer[1][0] = 2
         buffer[2][0] = 4
-        buffer[3][0] = 4
+        buffer[3][0] = 8
         buffer[4][0] = 8
         buffer[5][0] = 8
         buffer[6][0] = 16
-        buffer[7][0] = 16
-        buffer[8][0] = 32
-        buffer[9][0] = 64
-
+        buffer[7][0] = 32
+        buffer[8][0] = 64
+        self.draw_buffer(self.lcd.buffer)
         assert_equal(self.lcd.buffer, buffer)
 
     def test_fill_rect(self):