Design: 04.02.03.01/P11

This is an abstract, language-independent design. Grim details may be found in the corresponding source code. You may return to the documentation for the module containing this program design, or to the entire hierarchical table of topics covered by the PVT. 

PROGRAM 11: Geometric interaction of text attributes

CHARACTERISTICS: ynny

OPERATOR SCRIPT:

GEOMETRY OF TEXT ATTRIBUTES: Several text primitives in font #1 are
displayed.  The characters of all but one should be similar in size,
position, and orientation to the outline formed by the dashed
polylines.  Identify the primitive with an incorrect outline.

GEOMETRY OF NEGATIVE TEXT ATTRIBUTES: Same as for GEOMETRY OF
TEXT ATTRIBUTES, above.

DESIGN:

Throughout, use font#1 (monospaced), STROKE precision, color #1
for text, color #2 and dashed lines for outline

Throughout, use text string "ELF", because letters are simple to
outline, and asymmetric (to reveal reversals).
chstr = "ELF"

numlin = number of lines to display = 5

TEST: #SR 1 2 11 27 28 31 35 36 41 42 58 59 60 66 67 68 69 74 75 80 81
      "The transformation effects of text path, text alignment,
       and character up vector and of various positive values for
       character expansion factor, character spacing, and
       character height should work correctly in conjunction with
       the text direction vectors for a 3D test primitive."

Use <inquire text extent> to determine
  nomwid = nominal character width for font #1
  nombht = nominal character body height for font #1
  vtab   = list of nominal offsets for the various vertical
           text alignments, relative to BASE.
nominal quantities are for char-ht=1, char-sp=0, char-xp=1

ngline = random integer from 1 to numlin

set up random order for text paths, alignments - make sure each
  possible value is chosen at least once

do ix = 1 to numlin
   pick random values for text path, text alignment,
       and character up vector
   pick random positive values for character expansion factor,
       character spacing, and character height
   if (ix = ngline) then
      distort expected outline for ngline:
      expected position based on chht*1.25
   endif

   Represent position of text primitive in MC as follows:
      LLE  : 3D location of lower-left corner (LEFT,BASE) of "E"
      NXTC : vector to next character
      UPCH : character up 3D vector (direction and length)
      RTCH : character right 3D vector (direction and length)
      COR  : 3D location of (LEFT,BASE) corner of text extent rectangle
      CLNG : vector from corner along long dimension of rectangle
      CSHT : vector from corner along short dimension of rectangle

   Calculate expected TLC position of text primitive: apply
   attributes in this order:
      1: character expansion, character spacing, and text path
      2: text alignment
      3: character up
      4: character height

   pick random values for text position and direction vectors
   Calculate xf3d = expected rotation from TLC to MC
   apply xf3d to vectors: nxtc,upch,rtch,clng,csht
   Calculate xf3d = expected rotation and shift from TLC to MC
   apply xf3d to points: lle,cor

   Correct MC values for lle, nxtc, upch, rtch, cor, clng, csht
     now computed.

   compute and set global modelling transform to re-locate text
      extent rectangle (MC) to display area for this line (WC).

   re-set local transformation to identity; only global applies to
     actual text primitive.

   generate text primitive, with chosen attributes and geometry

   calculate and set local transformation to move outline to
     expected MC location.

   draw outline of expected text.
next ix

OPQA/GEOMETRY OF TEXT ATTRIBUTES: Which text primitive is NOT similar
  in size, position, and orientation to the dashed outline?
pass/fail depending on (primitive #ngline selected)

TEST: #SR 1 2 11 27 28 31 35 36 41 42 58 59 60 66 67 68 69 74 75 80 81
      "The transformation effects of text path, text alignment,
       and character up vector and of various negative values for
       character expansion factor, character spacing, and
       character height should work correctly in conjunction with
       the text direction vectors for a 3D test primitive."

Use <inquire text extent> to determine
  nomwid = nominal character width for font #1
  nombht = nominal character body height for font #1
  vtab   = list of nominal offsets for the various vertical
           text alignments, relative to BASE.
nominal quantities are for char-ht=1, char-sp=0, char-xp=1

ngline = random integer from 1 to numlin

set up random order for text paths, alignments - make sure each
  possible value is chosen at least once

do ix = 1 to numlin
   pick random values for text path, text alignment,
      and character up vector
   pick random mostly negative values for character expansion
      factor, character spacing, and character height
   if (ix = ngline) then
      distort expected outline for ngline:
      expected position based on chht*1.25
   endif

   Represent position of text primitive in MC as follows:
      LLE  : 3D location of lower-left corner (LEFT,BASE) of "E"
      NXTC : vector to next character
      UPCH : character up 3D vector (direction and length)
      RTCH : character right 3D vector (direction and length)
      COR  : 3D location of (LEFT,BASE) corner of text extent rectangle
      CLNG : vector from corner along long dimension of rectangle
      CSHT : vector from corner along short dimension of rectangle

   Calculate expected TLC position of text primitive: apply
   attributes in this order:
      1: character expansion, character spacing, and text path
      2: text alignment
      3: character up
      4: character height

   pick random values for text position and direction vectors
   Calculate xf3d = expected rotation from TLC to MC
   apply xf3d to vectors: nxtc,upch,rtch,clng,csht
   Calculate xf3d = expected rotation and shift from TLC to MC
   apply xf3d to points: lle,cor

   Correct MC values for lle, nxtc, upch, rtch, cor, clng, csht
     now computed.

   compute and set global modelling transform to re-locate text
      extent rectangle (MC) to display area for this line (WC).

   re-set local transformation to identity; only global applies to
     actual text primitive.

   generate text primitive, with chosen attributes and geometry

   calculate and set local transformation to move outline to
     expected MC location.

   draw outline of expected text.
next ix

OPQA/GEOMETRY OF NEGATIVE TEXT ATTRIBUTES: Which text primitive is NOT
  similar in size, position, and orientation to the dashed outline?
pass/fail depending on (primitive #ngline selected)

END PROGRAM 11