class documentation
        
        class DescartesCoordinateSystem(CoordinateSystem):
Class implementing a 2D Descartes coordinate system object.
| Method | __init__ | Initializes the coordinate system. | 
| Method | bbox | Sets the bounding box of the coordinate system | 
| Method | bounds | Sets the lower and upper bounds of the X and Y values | 
| Method | draw | Draws the coordinate system. | 
| Method | local | Converts local coordinates to the context coordinate system (given by the bounding box). | 
| Property | bbox | Returns the bounding box of the coordinate system | 
| Property | bounds | Returns the lower and upper bounds of the X and Y values | 
| Method | _recalc | Recalculates some cached scale factors used within the class | 
| Instance Variable | _bbox | Undocumented | 
| Instance Variable | _bounds | Undocumented | 
| Instance Variable | _ox | Undocumented | 
| Instance Variable | _ox2 | Undocumented | 
| Instance Variable | _oy | Undocumented | 
| Instance Variable | _oy2 | Undocumented | 
| Instance Variable | _sx | Undocumented | 
| Instance Variable | _sy | Undocumented | 
              Inherited from AbstractCairoDrawer (via CoordinateSystem):
            
| Instance Variable | context | Undocumented | 
| Method | _mark | Marks the given point with a small circle on the canvas. Used primarily for debugging purposes. | 
Initializes the coordinate system.
| Parameters | |
| context | the context on which the coordinate system will be drawn. | 
| bbox | the bounding box that will contain the coordinate system. | 
| bounds | minimum and maximum X and Y values in a 4-tuple. |