diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 09dba2d..4988888 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -1,3 +1,6 @@
+0.6.0
+    - tests
+    - fix area drawing
 0.5.0
     - tests
     - fix page drawing
diff --git a/gfxlcd/drawing/area.py b/gfxlcd/drawing/area.py
index 418a84b..c2ab129 100644
--- a/gfxlcd/drawing/area.py
+++ b/gfxlcd/drawing/area.py
@@ -32,48 +32,40 @@ 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 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
-            steps = self._calculate_steps(length, step, width)
-
+            step = height + 1
+            length = width // step
+            steps = self._calculate_line_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
-            steps = self._calculate_steps(length, step, height)
+            step = width + 1
+            length = height // step
+            steps = self._calculate_line_steps(length, step, height)
 
         delta_y = 0
         delta_x = 0
diff --git a/gfxlcd/drawing/page.py b/gfxlcd/drawing/page.py
index d5720ee..0e7f54e 100644
--- a/gfxlcd/drawing/page.py
+++ b/gfxlcd/drawing/page.py
@@ -18,37 +18,6 @@ class Page(Pixel, metaclass=abc.ABCMeta):
         self.buffer[pos_x][pos_y//8] |= 1 << (pos_y % 8)
         self.flush()
 
-    def _calculate_steps(self, length, step, required_length):
-        """calculate lineparts - helper"""
-        steps = [length for _ in range(0, step)]
-        if step * length < required_length:
-            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)
@@ -71,7 +40,7 @@ class Page(Pixel, metaclass=abc.ABCMeta):
             horizontal = True
             step = height + 1
             length = width // step
-            steps = self._calculate_steps(length, step, width)
+            steps = self._calculate_line_steps(length, step, width)
         else:
             height += 1
             if pos_y2 < pos_y1:
@@ -82,7 +51,7 @@ class Page(Pixel, metaclass=abc.ABCMeta):
             horizontal = False
             step = width + 1
             length = height // step
-            steps = self._calculate_steps(length, step, height)
+            steps = self._calculate_line_steps(length, step, height)
         delta_y = 0
         delta_x = 0
         for idx, step in enumerate(steps):
diff --git a/gfxlcd/drawing/pixel.py b/gfxlcd/drawing/pixel.py
index a3a7339..e54f6cc 100644
--- a/gfxlcd/drawing/pixel.py
+++ b/gfxlcd/drawing/pixel.py
@@ -104,3 +104,34 @@ class Pixel(object):
             else:
                 offset_x -= 1
                 err -= 2*offset_x + 1
+
+    def _calculate_line_steps(self, length, step, required_length):
+        """calculate lineparts - helper"""
+        steps = [length for _ in range(0, step)]
+        if step * length < required_length:
+            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_line_appendix(appendix)
+                elif idx > 0 and rest_even:
+                    appendix = self._calculate_line_appendix(appendix)
+                elif not rest_even:
+                    appendix = self._calculate_line_appendix(appendix)
+
+        return steps
+
+    def _calculate_line_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
diff --git a/gfxlcd/driver/null/area_driver.py b/gfxlcd/driver/null/area_driver.py
new file mode 100644
index 0000000..a27be79
--- /dev/null
+++ b/gfxlcd/driver/null/area_driver.py
@@ -0,0 +1,50 @@
+"""Area driver """
+import time
+from gfxlcd.abstract.driver import Driver
+
+
+class AreaDriver(Driver):
+    """Null communication driver"""
+    def __init__(self, width, height):
+        self.height = height
+        self.width = width
+        self.buffer = [[0] * self.height for x in range(self.width)]
+        self.area = {
+            'start_x': 0,
+            'start_y': 0,
+            'end_x': width,
+            'end_y': height
+        }
+        self.pointer = (0, 0)
+
+    def init(self):
+        """initialize pins"""
+        pass
+
+    def reset(self):
+        """reset a display"""
+        pass
+
+    def cmd(self, data, enable):
+        """send command to display"""
+        pass
+
+    def data(self, data, enable):
+        """send data to display"""
+        app_x, app_y = self.pointer
+        self.buffer[self.area['start_x'] + app_x][self.area['start_y'] + app_y] = data
+        self._inc_pointer()
+
+    def _inc_pointer(self):
+        app_x, app_y = self.pointer
+        app_x += 1
+        if self.area['start_x'] + app_x > self.area['end_x']:
+            app_x = 0
+            app_y += 1
+
+        if self.area['start_y'] + app_y > self.area['end_y']:
+            app_x = 0
+            app_y = 0
+
+        self.pointer = (app_x, app_y)
+
diff --git a/gfxlcd/driver/null/null_area.py b/gfxlcd/driver/null/null_area.py
new file mode 100644
index 0000000..dfd1ca6
--- /dev/null
+++ b/gfxlcd/driver/null/null_area.py
@@ -0,0 +1,36 @@
+"""Null Area test chip driver"""
+from gfxlcd.drawing.area import Area
+from gfxlcd.abstract.chip import Chip
+
+
+class NullArea(Area, Chip):
+    """Test chip driver for area drawing"""
+    def __init__(self, width, height, driver, auto_flush=True):
+        Chip.__init__(self, width, height, driver, auto_flush)
+        Area.__init__(self, driver)
+        self.rotation = 0
+
+    def _converted_background_color(self):
+        """dummy background color"""
+        return 2
+
+    def _converted_color(self):
+        """dummy color"""
+        return 1
+
+    def init(self):
+        """init display"""
+        self.driver.init()
+        Area.init(self)
+        Chip.init(self)
+        self.driver.reset()
+
+    def _set_area(self, pos_x1, pos_y1, pos_x2, pos_y2):
+        """set area to work on"""
+        self.driver.area = {
+            'start_x': pos_x1,
+            'start_y': pos_y1,
+            'end_x': pos_x2,
+            'end_y': pos_y2
+        }
+        self.driver.pointer = (0, 0)
diff --git a/gfxlcd/driver/null/null_page.py b/gfxlcd/driver/null/null_page.py
index 7915153..dbf83c4 100644
--- a/gfxlcd/driver/null/null_page.py
+++ b/gfxlcd/driver/null/null_page.py
@@ -1,4 +1,4 @@
-"""Null Page test chip drover"""
+"""Null Page test chip driver"""
 from gfxlcd.drawing.page import Page
 from gfxlcd.abstract.chip import Chip
 
diff --git a/gfxlcd/tests/test_area_drawing.py b/gfxlcd/tests/test_area_drawing.py
new file mode 100644
index 0000000..8b37f5b
--- /dev/null
+++ b/gfxlcd/tests/test_area_drawing.py
@@ -0,0 +1,272 @@
+import sys
+from nose.tools import assert_equal
+sys.path.append("../../")
+from gfxlcd.driver.null.null_area import NullArea
+from gfxlcd.driver.null.area_driver import AreaDriver
+
+
+class TestPageDrawing(object):
+    def setUp(self):
+        self.drv = AreaDriver(10, 16)
+        self.lcd = NullArea(10, 16, self.drv, False)
+        self.lcd.init()
+
+    def get_buffer(self):
+        return [[0] * 16 for x in range(10)]
+
+    def test_has_correct_size(self):
+        assert_equal(self.lcd.width, 10)
+        assert_equal(self.lcd.height, 16)
+
+    def test_empty_buffer_after_init(self):
+        assert_equal(self.drv.buffer, self.get_buffer())
+
+    def test_draw_pixel(self):
+        self.lcd.draw_pixel(1, 1)
+        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
+        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
+        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
+        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
+        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
+        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
+        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
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_rect(self):
+        self.lcd.draw_rect(2, 2, 7, 11)
+        buffer = self.get_buffer()
+        buffer[2][2] = 1
+        buffer[2][3] = 1
+        buffer[2][4] = 1
+        buffer[2][5] = 1
+        buffer[2][6] = 1
+        buffer[2][7] = 1
+        buffer[2][8] = 1
+        buffer[2][9] = 1
+        buffer[2][10] = 1
+        buffer[2][11] = 1
+        buffer[7][2] = 1
+        buffer[7][3] = 1
+        buffer[7][4] = 1
+        buffer[7][5] = 1
+        buffer[7][6] = 1
+        buffer[7][7] = 1
+        buffer[7][8] = 1
+        buffer[7][9] = 1
+        buffer[7][10] = 1
+        buffer[7][11] = 1
+
+        buffer[3][2] = 1
+        buffer[4][2] = 1
+        buffer[5][2] = 1
+        buffer[6][2] = 1
+        buffer[3][11] = 1
+        buffer[4][11] = 1
+        buffer[5][11] = 1
+        buffer[6][11] = 1
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_fill_rect(self):
+        self.lcd.fill_rect(2, 2, 7, 11)
+        buffer = self.get_buffer()
+        for x in range(6):
+            for y in range(10):
+                buffer[2+x][2+y] = 2
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_circle(self):
+        self.lcd.draw_circle(5, 8, 3)
+        buffer = self.get_buffer()
+        buffer[2][7] = 1
+        buffer[2][8] = 1
+        buffer[2][9] = 1
+        buffer[3][6] = 1
+        buffer[3][7] = 1
+        buffer[3][9] = 1
+        buffer[3][10] = 1
+        buffer[4][5] = 1
+        buffer[4][6] = 1
+        buffer[4][10] = 1
+        buffer[4][11] = 1
+        buffer[5][5] = 1
+        buffer[5][11] = 1
+        buffer[6][5] = 1
+        buffer[6][6] = 1
+        buffer[7][6] = 1
+        buffer[7][7] = 1
+        buffer[8][7] = 1
+        buffer[8][8] = 1
+        buffer[8][9] = 1
+        buffer[7][9] = 1
+        buffer[7][10] = 1
+        buffer[6][10] = 1
+        buffer[6][11] = 1
+        assert_equal(self.drv.buffer, buffer)
+
+    def test_draw_arc(self):
+        self.lcd.draw_arc(5, 8, 3, 90, 270)
+        buffer = self.get_buffer()
+        buffer[2][7] = 1
+        buffer[2][8] = 1
+        buffer[2][9] = 1
+        buffer[3][6] = 1
+        buffer[3][7] = 1
+        buffer[3][9] = 1
+        buffer[3][10] = 1
+        buffer[4][5] = 1
+        buffer[4][6] = 1
+        buffer[4][10] = 1
+        buffer[4][11] = 1
+        buffer[5][5] = 1
+        buffer[5][11] = 1
+        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 ad825de..98abfe1 100644
--- a/gfxlcd/tests/test_page_drawing.py
+++ b/gfxlcd/tests/test_page_drawing.py
@@ -7,7 +7,6 @@ from gfxlcd.driver.null.null_page import NullPage
 class TestPageDrawing(object):
     def setUp(self):
         self.lcd = NullPage(10, 16, None, False)
-        self.buffer = [[0] * (16 // 8) for x in range(10)]
         self.lcd.init()
 
     def get_buffer(self):
@@ -18,7 +17,7 @@ class TestPageDrawing(object):
         assert_equal(self.lcd.height, 16)
 
     def test_empty_buffer_after_init(self):
-        assert_equal(self.lcd.buffer, self.buffer)
+        assert_equal(self.lcd.buffer, self.get_buffer())
 
     def test_draw_pixel(self):
         self.lcd.draw_pixel(1, 1)
@@ -104,7 +103,6 @@ class TestPageDrawing(object):
         buffer[7][1] = 16+32
         buffer[8][1] = 64
         buffer[9][1] = 128
-        self.draw_buffer(self.lcd.buffer)
         assert_equal(self.lcd.buffer, buffer)
 
     def test_draw_diagonal_line_even_steps_even_rest(self):
@@ -120,7 +118,6 @@ class TestPageDrawing(object):
         buffer[7][0] = 16
         buffer[8][0] = 16
         buffer[9][0] = 32
-
         assert_equal(self.lcd.buffer, buffer)
 
     def test_draw_diagonal_line_odd_steps_even_rest(self):
@@ -136,23 +133,38 @@ class TestPageDrawing(object):
         buffer[7][0] = 16
         buffer[8][0] = 32
         buffer[9][0] = 64
-
         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
+        assert_equal(self.lcd.buffer, buffer)
 
+    def test_draw_rect(self):
+        self.lcd.draw_rect(2, 2, 7, 11)
+        buffer = self.get_buffer()
+        buffer[2][0] = 4+8+16+32+64+128
+        buffer[3][0] = 4
+        buffer[4][0] = 4
+        buffer[5][0] = 4
+        buffer[6][0] = 4
+        buffer[7][0] = 4+8+16+32+64+128
+
+        buffer[2][1] = 1+2+4+8
+        buffer[3][1] = 8
+        buffer[4][1] = 8
+        buffer[5][1] = 8
+        buffer[6][1] = 8
+        buffer[7][1] = 1+2+4+8
         assert_equal(self.lcd.buffer, buffer)
 
     def test_fill_rect(self):
@@ -202,7 +214,6 @@ class TestPageDrawing(object):
         buffer[3][1] = 2+4
         buffer[4][1] = 4+8
         buffer[5][1] = 8
-        self.draw_buffer(self.lcd.buffer)
         assert_equal(self.lcd.buffer, buffer)
 
     def draw_buffer(self, buffer):
diff --git a/setup.py b/setup.py
index a5e5a46..52f6792 100644
--- a/setup.py
+++ b/setup.py
@@ -13,7 +13,7 @@ def read(*paths):
 
 setup(
     name='gfxlcd',
-    version='0.4.0',
+    version='0.6.0',
     description='gfxlcd is a handler for graphical lcds: ILI9328, SSD1306, NJU6450, touch panel: AD7843 @ Raspberry Pi.',
     keywords=[
         'gfxlcd', 'raspberry pi' ,'ili9328' ,'ssd1306', 'nju6450', 'lcd', 'graphical lcd', 'touch panel', 'ad7843',