/*!

\page create_sketcher_page 2D Sketcher

The 2D Sketcher allows you to draw 2D shapes on a working plane. You
can create sketches of two types:

<ul>
<li> \b Profile made of connected curves of 2 types: <b>line segments</b> and \b arcs.

\b or

<li>  \b Rectangle
</ul>

The \b Result is a \b Wire

\n <b>Example:</b>

\image html sketch_example.png

To create a <b> 2D Sketch</b>:

<ol>
<li>In the main menu select <b>New Entity -> Basic -> 2D Sketch</b> or click on \image html sketch.png </li>

<li> Select the \b plane or the <b>planar face</b> on which to create the sketch. 
\note By default the sketch is created on the XOY plane of the global coordinate system.
If Local Coordinate Systems have been created in the study they appear
in the combo-box and can be selected as a reference coordinate system.</li>

<li> Choose a \b segment or an \b arc element to start a \b profile or choose \b rectangle to draw a rectangle.

\n If you draw a \b profile:

<li> Select a start point. By default the start point of the curve is located at the point of
origin of the reference coordinate system.</li>

<li> Create curve portions and click on \b Apply after each step.</li>

<li> Select either \b Close or <b>Sketch Closure</b> if you want to close the profile before closing the window.</li>
</ol>

\n To create a \b Segment:

<ol>
<li> In the <b>Element Type</b> part of the dialog box select:

\image html line_icon.png </li>

<li> You can define the segment by either its <b>end point</b> or \b direction and \b length. The direction is defined relatively to the tangent at the last point of the sketch. It can be:
  <ul>
    <li> Tangent (collinear to the tangent at the last point)</li>
    <li> Perpendicular</li>
    <li> Defined by an angle</li>
    <li> Defined by a vector (Vx, Vy)</li>
  </ul>

</li>

</ol>
  
\n To create an \b Arc:

<ol>
<li> In the <b>Element Type</b> part of the dialog box select \image html arc_icon.png </li>

<li> You can define the segment by either its <b>end point</b> or \b direction \b radius and \b angle. </li>

<ul>
  <li>In case of an end point the arc can be built in three different ways:</li>
  <ul>
    <li>From the end point only. The arc is \b tangential to the end of the sketch.</li>
    <li>From the end point and a \b radius. (The radius must be greater than half of the distance between the last point and the end point of the arc).</li>
    <li>From the \b center of the circle and the end point. The constraint on the center is first taken into account.
    The destination point is only used to define the angle of the arc and won't lie on the arc in the general case.</li>
  </ul>
  
  <li>The direction is defined relatively to the tangent at the last point of the sketch. It can be:</li>
  
  <ul>
    <li>Tangent (colinear to the tangent at the last point)</li><
    <li>Perpendicular</li>
    <li>Defined by an angle</li>
    <li>Defined by a vector (Vx, Vy)</li>
  </ul>
</ul>
    
</ol>

\note For the first segment or arc of the sketch the reference direction is the X direction of the reference coordinate system.

\n <b>Dialog Box:</b>

\image html sketcher_dlg.png

\n <b>Arguments:</b>
<ol>
<li>Coordinate system (Existing Local CS or Global CS can be selected)</li>
<li>A plane or a planar face to define a new Local Coordinate System
<li>Element type (segment, arc or rectangle).</li>
<li>Destination type (point or direction).</li>
<li>Destination point by means of:</li>
<ul>
<li>absolute coordinates X,Y;</li>
<li>relative coordinates DX, DY (with respect to the current point);</li>
<li>selection of an existing point.</li>
</ul>
<li>Destination direction by means of:</li>
<ul>
<li>angle between the new segment and the previous one;</li>
<li>perpendicular to the previous segment (same as previous, but the angle
is predefined and is equal to 90 degrees);</li>
<li>tangent to the previous segment;</li>
<li>vector components DX, DY.</li>
</ul>
<li>Parameters of an element (for segment : length or target X or Y coordinate value, for arc : radius, angle or center coordinates).</li>
</ol>

\b Buttons:

<b>"Restore"</b> button orientates the viewer correspondingly to the chosen working plane and fits the scene to show all its objects. 
\n <b>"Close"</b> button applies the wire, only the red part will be built.
\n <b>"Sketch Closure"</b> will close the Sketch by a straight line
from the last red part and apply it.

\n To draw a \b rectangle:

<ol>
<li> In the <b>Element Type</b> part of the dialog box select \image html rectangle_icon.png </li>

<li> Draw a rectangle with the mouse directly in the view or fill in the coordinates of two opposite vertices of the rectangle.</li>
<li> <b>Apply and Close</b> </li>
</ol>

\n <b>Dialog Box:</b>

\image html sketcher_dlg2.png

\n <b>Arguments:</b>
<ol>
<li>Coordinate system (Existing Local CS or Global CS can be selected)</li>
<li>A plane or a planar face to define a new Local Coordinate System
<li>Element type (segment, arc or rectangle).</li>
<li>The X,Y coordinates of two opposite vertices of the rectangle</li>
</ol>


\n <b>TUI Command:</b> <em>geompy.MakeSketcherOnPlane(Command, WorkingPlane)</em>
\n This algorithm creates a sketcher (wire or face), following the
textual description, passed through the Command argument. The edges of
the resulting wire or face will be arcs of circles and/or linear
segments.
\n \em Command is a string, defining the sketcher by the coordinates of
points in the current LCS.
\n <em>WorkingPlane</em> can be a Local CS, a plane, or a planar face.

\n Another way to create the 2D Sketcher in TUI is using Sketcher2D
interface.

<b>TUI Command:</b> <em>sk = geompy.Sketcher2D()</em>

Returns an instance of Sketcher2D interface <i>sk</i>.

Use the below examples and see the \ref gsketcher.Sketcher2D "Sketcher2D"
interface documentation for more information.

Our <b>TUI Scripts</b> provide you with useful examples of the use of
\ref tui_sketcher_page "2D Sketcher".
*/