Document rough canvas

Signed-off-by: martinRenou <[email protected]>

Author: martinRenou

docs/source/images/bowing.png

@@ -0,0 +1,118 @@
+Rough Canvas
+============
+
+ipycanvas provides a special canvas class that automatically gives a hand-drawn style to your drawings.
+The ``RoughCanvas`` API is the same as the ``Canvas`` one, except that it provides a few more options.
+
+Create a RoughCanvas
+--------------------
+
+You create a ``RoughCanvas`` the same way you would create a normal ``Canvas``.
+
+.. code:: Python
+
+    from ipycanvas import RoughCanvas
+
+    canvas = RoughCanvas(width=200, height=200)
+    canvas
+
+Then your drawings will have an hand-drawn style:
+
+
+.. code:: Python
+
+    from ipycanvas import RoughCanvas
+
+    canvas = RoughCanvas()
+
+    canvas.stroke_style = 'red'
+    canvas.fill_style = 'blue'
+    canvas.stroke_rect(100, 100, 100, 100)
+    canvas.fill_rect(50, 50, 100, 100)
+
+    canvas.stroke_style = 'purple'
+    canvas.fill_style = 'green'
+    canvas.stroke_circle(300, 300, 100)
+    canvas.fill_circle(350, 350, 100)
+
+    canvas.stroke_line(200, 200, 300, 300)
+
+    canvas
+
+.. image:: images/roughshapes.png
+
+.. note::
+    The ``RoughCanvas`` does not support yet applying the hand-drawn style to custom path commands (``begin_path``, ``arc_to``, etc)
+
+Fill style
+----------
+
+The ``RoughCanvas`` provides a second fill style option ``rough_fill_style`` which changes the way shapes are filled.
+
+.. code:: Python
+
+    from ipycanvas import RoughCanvas
+
+    canvas = RoughCanvas(width=850, height=100)
+
+    canvas.fill_style = 'blue'
+    canvas.line_width = 2.
+
+    rough_fill_style_values = ['hachure', 'solid', 'zigzag', 'cross-hatch', 'dots', 'sunburst', 'dashed', 'zigzag-line']
+
+    for i in range(len(rough_fill_style_values)):
+        canvas.rough_fill_style = rough_fill_style_values[i]
+
+        canvas.fill_rect(10 + i * 100, 10, 90, 80)
+
+    canvas
+
+.. image:: images/roughfillstyle.png
+
+
+Roughness
+---------
+
+You can change the roughness of your drawing changing the ``roughness`` attribute (float).
+A rectangle with the roughness of 0 would be a perfect rectangle. There is no upper limit to this value, but a value over 10 is mostly useless.
+
+.. code:: Python
+
+    from ipycanvas import RoughCanvas
+
+    canvas = RoughCanvas(width=850, height=100)
+
+    canvas.fill_style = 'green'
+
+    for i in range(8):
+        canvas.roughness = i
+
+        canvas.fill_rect(10 + i * 100, 10, 90, 80)
+
+    canvas
+
+.. image:: images/roughness.png
+
+
+Bowing
+------
+
+You can change the curves of your drawing changing the ``bowing`` attribute (float).
+It's a numerical value indicating how curvy the lines are when drawing a sketch. A value of 0 will cause straight lines.
+
+.. code:: Python
+
+    from ipycanvas import RoughCanvas
+
+    canvas = RoughCanvas(width=850, height=150)
+
+    canvas.fill_style = 'green'
+
+    for i in range(8):
+        canvas.bowing = i * 3.
+
+        canvas.stroke_rect(20 + i * 100, 20, 90, 110)
+
+    canvas
+
+.. image:: images/bowing.png

docs/source/images/roughfillstyle.png

@@ -9,6 +9,7 @@ Usage
     drawing_shapes
     drawing_paths
     styles_and_colors
+    rough_canvas
     drawing_text
     drawing_images
     retrieve_images