diff --git a/lichartee.js b/lichartee.js
index c695cb5..2c973ed 100644
--- a/lichartee.js
+++ b/lichartee.js
@@ -1,5 +1,19 @@
+/**
+ * a manager allows to manipulate multiple canvas
+ *
+ * it's different from matplotlib, where the manager can only store one
+ * canvas
+ *
+ * @property Element parent_element DOM element containing every canvas
+ *                                  of this manager
+ * @property 1darray<Canvas> list_canvas List of canvas held by this
+ *                                       manager
+ */
 class Manager
 {
+	/**
+	 * @param Element parent_element Element holding the canvas
+	 */
 	constructor(parent_element)
 	{
 		this.parent_element = parent_element;
@@ -41,6 +55,9 @@ class Manager
 		return canvas;
 	}
 
+	/**
+	 * draw every canvas
+	 */
 	draw()
 	{
 		for (const index in this.list_canvas)
@@ -49,6 +66,11 @@ class Manager
 		}
 	}
 
+	/**
+	 * remove a canvas
+	 *
+	 * @param int position Position of the canvas to remove
+	 */
 	remove_canvas(position = 0)
 	{
 		document.removeChild(this.list_canvas[position].ctx.canvas);
@@ -56,14 +78,27 @@ class Manager
 	}
 }
 
+/**
+ * a canvas allows to render a figure
+ *
+ * @property CanvasRenderingContext2D ctx Canvas API interface
+ * @property Figure figure Figure held by this canvas
+ */
 class Canvas
 {
+	/**
+	 * @param CanvasRenderingContext2D ctx Canvas API interface
+	 * @param Figure figure Figure held by this canvas
+	 */
 	constructor(ctx, figure)
 	{
 		this.ctx    = ctx   ;
 		this.figure = figure;
 	}
 
+	/**
+	 * render the figure to the canvas
+	 */
 	draw()
 	{
 		if (this.figure instanceof Figure.constructor)
@@ -132,6 +167,15 @@ class Canvas
 	}
 }
 
+/**
+ * a figure hold axes and every plot elements
+ *
+ * @property int width Total width of this figure (related to each
+ *                     axes)
+ * @property int height Total height of this figure (related to each
+ *                     axes)
+ * @property 1darray<Axes> list_axes List of every axes
+ */
 class Figure
 {
 	constructor()
@@ -141,6 +185,13 @@ class Figure
 		this.list_axes = [];
 	}
 
+	/**
+	 * add axes to this figure
+	 *
+	 * @param int relative_width Relative width of the new axes
+	 * @param int relative_height Relative height of the new axes
+	 * @param int position Position of the axes in the figure
+	 */
 	add_axes(relative_width = 50, relative_height = 50, position = 0)
 	{
 		this.width  += relative_width ;
@@ -150,49 +201,110 @@ class Figure
 		return axes;
 	}
 
+	/**
+	 * remove an axes
+	 *
+	 * @param int position Position of the axes in the figure to delete
+	 */
 	remove_axes(position)
 	{
 		this.list_axes.splice(position, 1);
 	}
 }
 
+/**
+ * an axes represents one plot in a figure.
+ *
+ * @property int width Width of the axes
+ * @property int height Height of the axes
+ * @property String title Title of the axes
+ * @property 1darray<Line> lines List of lines
+ */
 class Axes
 {
+	/**
+	 * @param int width Width of the axes
+	 * @param int height Height of the axes
+	 * @param String title Title of the axes
+	 */
 	constructor(
 		width    = 100      ,
 		height   = 100      ,
-		position = 0        ,
 		title    = ''       ,
 	)
 	{
 		this.width    = width   ;
 		this.height   = height  ;
-		this.position = position;
 		this.title    = title   ;
 		this.lines    = []      ;
 	}
 
-	plot(x, y, linestyle = undefined, label = '')
+	/**
+	 * plot y versus x as lines
+	 *
+	 * @param 1darray<Number> x x data
+	 * @param 1darray<Number> y y data
+	 * @param object linestyle Object defining a style for a line. The
+	 *                         structure of the object should be:
+	 *                         {
+	 *                           color: color
+	 *                           style: style
+	 *                         }
+	 *                         where color is a string containing
+	 *                         "rgb(x,y,z)", "#abcdef" or a name of
+	 *                         a color, and style is "solid", "dotted",
+	 *                         "dashdot" or "dashed". Default value is
+	 *                         color = "black" and style = "solid"
+	 * @param String label Label that will be displayed in the legend
+	 */
+	plot(x, y, linestyle = {color: "black", style: "solid"}, label = '')
 	{
-		if (linestyle === undefined)
-		{
-			linestyle = {
-				color: 'rgb(0,0,0)',
-				style: 'solid'
-			};
-		}
 		let line = new Line(x, y, linestyle, label);
 		this.lines.push(line);
 	}
 }
 
+/**
+ * a line, with a color and a line style
+ *
+ * @property 1darray<float> x xdata
+ * @property 1darray<float> y ydata
+ * @property object linestyle Object defining a style for a line. The
+ *                            structure of the object should be:
+ *                            {
+ *                              color: color
+ *                              style: style
+ *                            }
+ *                            where color is a string containing
+ *                            "rgb(x,y,z)", "#abcdef" or a name of
+ *                            a color, and style is "solid", "dotted",
+ *                            "dashdot" or "dashed". Default value is
+ *                            color = "black" and style = "solid"
+ * @property String label Label that will be displayed in the legend
+ */
 class Line
 {
+	/**
+	 * @param 1darray<float> x xdata
+	 * @param 1darray<float> y ydata
+	 * @param object linestyle Object defining a style for a line. The
+	 *                         structure of the object should be:
+	 *                         {
+	 *                           color: color
+	 *                           style: style
+	 *                         }
+	 *                         where color is a string containing
+	 *                         "rgb(x,y,z)", "#abcdef" or a name of
+	 *                         a color, and style is "solid", "dotted",
+	 *                         "dashdot" or "dashed". Default value is
+	 *                         color = "black" and style = "solid"
+	 * @param String label Label that will be displayed in the legend
+	 */
 	constructor(
-		x                     ,
-		y                     ,
-		linestyle = undefined ,
-		label = ''
+		x                                           ,
+		y                                           ,
+		linestyle = {color: "black", style: "solid"},
+		label     = ''
 	)
 	{
 		this.x          = x         ;
@@ -204,7 +316,7 @@ class Line
 	/**
 	 * draw the line in the box coordinate
 	 *
-	 * @param ctx           ctx  Context of the canvas
+	 * @param CanvasRenderingContext2d ctx  Context of the canvas
 	 * @param 2dlist<int>   box  Box where to draw the line
 	 * @param 2dlist<float> view Scale of the box (link value <->
 	 *                           coordinate
@@ -271,6 +383,13 @@ class Line
 	}
 }
 
+/**
+ * get max or min of a 1d array of number
+ *
+ * @param 1darray<number> array Array where to get max values
+ * @param function f Math.max or Math.min if we want max or min value
+ * @param int sign -1 if max, 1 if min
+ */
 function get_ext_array(array, f = Math.max, sign = -1)
 {
 	return array.reduce(