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4.6 Texts

The notion of text within the 3D space needs to be clarified. In this context, we can distinguish between two types of texts: the graphics text and description text. The graphics text is the text which forms part of the picture and which is painted onto the surface. This text must therefore undergo all the transformations applied to the surface. The description text is the text whose origin (lower left corner of the first character) corresponds to a point in the space, but which is defined on the visualization surface in order to describe the object's graphical representation.

•       SUBROUTINE TXT3D(STRING, NB, X, Y, Z)
        CHARACTER*(*) STRING
        INTEGER NB
        REAL X, Y, Z
  

  plots the text    consisting of NB characters contained in array STRING (description text), beginning at the projection of point with coordinates (X, Y, Z) onto the visualization surface The current cursor position becomes position (X, Y, Z).

•       SUBROUTINE STRSFT(TEXT,NBCHAR,POSIT,DIRECR,DIRBAS,ANGSHR,L,H,
                          SEG,POL)
        CHARACTER*(*) TEXT
        REAL POSIT(3), DIRECR(3), DIRBAS(3), ANGSHR, L, H
        EXTERNAL SEG, POL
  

  plots   text (graphics) TEXT of NBCHAR characters positioned at POSIT, where:

  • DIRECR: Directional vector for the text and also the inter-character spacing.
  • DIRBAS: Directional vector for the bottom of the characters.
  • ANGSHR: Character shearing angle with respect to the normal to DIRBAS.
  • L: Character length.
  • H: Character height.
  • SEG: Subroutine plotting a segment, with the form:

                     SUBROUTINE SEG(X1, Y1, X2, Y2)
                     REAL X1, Y1, X2, Y2
    

    This subroutine must be supplied by the user. The simplest case corresponds to, for the 2D case:

                     CALL MOV2TO(X1, Y1)
                     CALL LIN2TO(X2, Y2)
    

    and, for the 3D case:

                     CALL MOV3TO(X1, Y1, 0. )
                     CALL LIN3TO(X2, Y2, 0. )
    

    However, the subroutine can be defined to plot other types of lines (dotted, cylindrical volume, waves, ...). The characters will then be plotted with this line definition.

  • POL: Subroutine plotting a typeface, a choice between: POLIC1, POLIC2, POLIC3:
    • The alphabet of POLIC1 is:

                   #$%`()*+, -./0123456789=?
                    ABCDEFGHIJKLMNOPQRSTUVWXYZ
      

    • The alphabet of POLIC2 is:

                    `()*+, -./0123456789=?
                    ABCDEFGHIJKLMNOPQRSTUVWXYZ
      

    • The alphabet of POLIC3 is:

                    !"#$%&`~()*+, -./0123456789:;<=>?
                    ABCDEFGHIJKLMNOPQRSTUVWXYZ^@
                    abcdefghijklmnopqrstuvwxyz
      

  Subroutine STRSFT is common to libraries 2D and 3D.