class TPostScript: public TVirtualPS

 Default PostScript constructor

 Initialize the PostScript interface

  fname : PostScript file name
  wtype : PostScript workstation type


  The possible workstation types are:
     111 ps  Portrait
     112 ps  Landscape
     113 eps

 Open a PostScript file

 Default PostScript destructor

 Close a PostScript file

 Activate an already open PostScript file

 Deactivate an already open PostScript file

 Draw a Cell Array

 Drawing a PostScript Cell Array is in fact done thanks to three
 procedures: CellArrayBegin, CellArrayFill, and CellArrayEnd.

 CellArrayBegin: Initiate the Cell Array by writing the necessary
                 PostScript procedures and the initial values of the
                 required parameters. The input parameters are:
                 W: number of boxes along the width.
                 H: number of boxes along the height
                 x1,x2,y1,y2: First box coordinates.
 CellArrayFill:  Is called for each box of the Cell Array. The first
                 box is the top left one and the last box is the
                 bottom right one. The input parameters are the Red,
                 Green, and Blue components of the box colour. These
                 Levels are between 0 and 255.
 CellArrayEnd:   Finishes the Cell Array.

 PostScript cannot handle arrays larger than 65535. So the Cell Array
 is drawn in several pieces.

 Paint the Cell Array

 End the Cell Array painting

 Define the markers

 Draw a Box

 Draw a Frame around a box

 mode = -1  box looks as it is behind the screen
 mode =  1  box looks as it is in front of the screen
 border is the border size in already precomputed PostScript units
 dark  is the color for the dark part of the frame
 light is the color for the light part of the frame

 Draw a PolyLine

  Draw a polyline through  the points xy.
  If nn=1 moves only to point x,y.
  If nn=0 the x,y are  written  in the PostScript file
          according to the current transformation.
  If nn>0 the line is clipped as a line.
  If nn<0 the line is clipped as a fill area.

 Draw a PolyLine in NDC space

  Draw a polyline through the points xy.
  If nn=1 moves only to point x,y.
  If nn=0 the x,y are  written  in the PostScript file
          according to the current transformation.
  If nn>0 the line is clipped as a line.
  If nn<0 the line is clipped as a fill area.

 Draw markers at the n WC points x, y

 Draw markers at the n WC points x, y

 Draw a PolyLine

  Draw a polyline through the points xw,yw.
  If nn=1 moves only to point xw,yw.
  If nn=0 the XW(1) and YW(1) are  written  in the PostScript file
          according to the current NT.
  If nn>0 the line is clipped as a line.
  If nn<0 the line is clipped as a fill area.

 Draw a PolyLine

 Draw a polyline through  the points xw,yw.
 If nn=1 moves only to point xw,yw.
 If nn=0 the xw(1) and YW(1) are  written  in the PostScript file
         according to the current NT.
 If nn>0 the line is clipped as a line.
 If nn<0 the line is clipped as a fill area.

 Draw Fill area with hatch styles

 Draw Fill area with hatch styles

 Font Reencoding

 PostScript Initialisation

 This routine initialize the following PostScript procedures:

 +------------+------------------+-----------------------------------+
 | Macro Name | Input parameters |            Explanation            |
 +------------+------------------+-----------------------------------+
 |     l      | x y              | Draw a line to the x y position   |
 +------------+------------------+-----------------------------------+
 |     m      | x y              | Move to the position x y          |
 +------------+------------------+-----------------------------------+
 |     box    | dx dy x y        | Define a box                      |
 +------------+------------------+-----------------------------------+
 |     bl     | dx dy x y        | Draw a line box                   |
 +------------+------------------+-----------------------------------+
 |     bf     | dx dy x y        | Draw a filled box                 |
 +------------+------------------+-----------------------------------+
 |     sw     | text             | Return string width of text       |
 +------------+------------------+-----------------------------------+
 |     t      | x y              | Translate                         |
 +------------+------------------+-----------------------------------+
 |     r      | angle            | Rotate                            |
 +------------+------------------+-----------------------------------+
 |     rl     | i j              | Roll the stack                    |
 +------------+------------------+-----------------------------------+
 |     d      | x y              | Draw a relative line to x y       |
 +------------+------------------+-----------------------------------+
 |     X      | x                | Draw a relative line to x (y=0)   |
 +------------+------------------+-----------------------------------+
 |     Y      | y                | Draw a relative line to y (x=0)   |
 +------------+------------------+-----------------------------------+
 |     rm     | x y              | Move relatively to x y            |
 +------------+------------------+-----------------------------------+
 |     gr     |                  | Restore the graphic context       |
 +------------+------------------+-----------------------------------+
 |     lw     | lwidth           | Set line width to lwidth          |
 +------------+------------------+-----------------------------------+
 |     sd     | [] 0             | Set dash line define by []        |
 +------------+------------------+-----------------------------------+
 |     s      |                  | Stroke mode                       |
 +------------+------------------+-----------------------------------+
 |     c      | r g b            | Set rgb color to r g b            |
 +------------+------------------+-----------------------------------+
 |     cl     |                  | Close path                        |
 +------------+------------------+-----------------------------------+
 |     f      |                  | Fill the last describe path       |
 +------------+------------------+-----------------------------------+
 |     mXX    | x y              | Draw the marker type XX at (x,y)  |
 +------------+------------------+-----------------------------------+
 |     Zone   | ix iy            | Define the current zone           |
 +------------+------------------+-----------------------------------+
 |     black  |                  | The color is black                |
 +------------+------------------+-----------------------------------+
 |     C      | dx dy x y        | Clipping on                       |
 +------------+------------------+-----------------------------------+
 |     NC     |                  | Clipping off                      |
 +------------+------------------+-----------------------------------+
 |     R      |                  | repeat                            |
 +------------+------------------+-----------------------------------+

 Move to a new position

 Move to a new PostScript page

 Set the range for the paper in centimeters

 Compute number of gsaves for restore
 This allows to write the correct number of grestore at the
 end of the PS file.

 Set color index for fill areas

 Patterns definition

 Define the pattern ipat in the current PS file. ipat can vary from
 1 to 25. Together with the pattern, the color (color) in which the
 pattern has to be drawn is also required. A pattern is defined in the
 current PS file only the first time it is used. Some level 2
 Postscript functions are used, so on level 1 printers, patterns will
 not work. This is not a big problem because patterns are
 defined only if they are used, so if they are not used a PS level 1
 file will not be polluted by level 2 features, and in any case the old
 patterns used a lot of memory which made them almost unusable on old
 level 1 printers. Finally we should say that level 1 devices are
 becoming very rare. The official PostScript is now level 3 !

 Set color index for lines

 Set the value of the global parameter TPostScript::fgLineJoin.
 This parameter determines the appearance of joining lines in a PostScript
 output.
 It takes one argument which may be:
   - 0 (miter join)
   - 1 (round join)
   - 2 (bevel join)
 The default value is 0 (miter join).

 To change the line join behaviour just do:
 TPostScript::SetLineJoin(2); // Set the PS line join to bevel.

 Change the line style

   linestyle = 2 dashed
             = 3  dotted
             = 4  dash-dotted
              else = solid

 See TStyle::SetLineStyleString for style definition

 Change the line width

 Set color index for markers

 Set the current color.

 Set directly current color (don't go via TColor).

 Set color index for text

 Write a string of characters

 This routine writes the string chars into a PostScript file
 at position xx,yy in world coordinates.

 Write a string of characters in NDC

 Convert U from NDC coordinate to PostScript

 Convert V from NDC coordinate to PostScript

 Convert X from world coordinate to PostScript

 Convert Y from world coordinate to PostScript

 Initialize the PostScript page in zones