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20. Some Larger Examples

Here are a few larger examples, with complete source code. One of our earlier examples is generated in an instructive way using a for loop:

     .PS
     # Draw a demonstration up left arrow with grid box overlay
     define gridarrow
     {
         move right 0.1
         [
             {arrow up left $1;}
             box wid 0.5 ht 0.5 dotted with .nw at last arrow .end;
             for i = 2 to ($1 / 0.5) do
             {
                 box wid 0.5 ht 0.5 dotted with .sw at last box .se;
             }
             move down from last arrow .center;
             [
                 if ( $1 == boxht ) \
                 then { "\fBline up left\fP" } \
                 else { sprintf("\fBarrow up left %g\fP", $1) };
             ]
         ]
         move right 0.1 from last [] .e;
     }
     gridarrow(0.5);
     gridarrow(1);
     gridarrow(1.5);
     gridarrow(2);
     undef gridarrow
     .PE


Figure 20-1: Diagonal arrows (dotted boxes show the implied 0.5-inch grid)

Here’s an example concocted to demonstrate layout of a large, multiple-part pattern:

     .PS
     define filter {box ht 0.25 rad 0.125}
     lineht = 0.25;
     Top: [
         right;
         box "\fBms\fR" "sources";
         move;
         box "\fBHTML\fR" "sources";
         move;
         box "\fBlinuxdoc-sgml\fP" "sources" wid 1.5;
         move;
         box "\fBTexinfo\fP" "sources";


         line down from 1st box .s lineht;
         A: line down;
         line down from 2nd box .s; filter "\fBhtml2ms\fP";
         B: line down;
         line down from 3rd box .s; filter "\fBformat\fP";
         C: line down;
         line down from 4th box .s; filter "\fBtexi2roff\fP";
         D: line down;
     ]
     move down 1 from last [] .s;
     Anchor: box wid 1 ht 0.75 "\fBms\fR" "intermediate" "form";
     arrow from Top.A.end to Anchor.nw;
     arrow from Top.B.end to 1/3 of the way between Anchor.nw and Anchor.ne;
     arrow from Top.C.end to 2/3 of the way between Anchor.nw and Anchor.ne;
     arrow from Top.D.end to Anchor.ne
     {
         # PostScript column
         move to Anchor .sw;
         line down left then down ->;
         filter "\fBpic\fP";
         arrow;
         filter "\fBeqn\fP";
         arrow;
         filter "\fBtbl\fP";
         arrow;
         filter "\fBgroff\fP";
         arrow;
         box "PostScript";


         # HTML column
         move to Anchor .se;
         line down right then down ->;
         A: filter dotted "\fBpic2img\fP";
         arrow;
         B: filter dotted "\fBeqn2html\fP";
         arrow;
         C: filter dotted "\fBtbl2html\fP";
         arrow;
         filter "\fBms2html\fP";
         arrow;
         box "HTML";


         # Nonexistence caption
         box dashed wid 1 at B + (2,0) "These tools" "don’t yet exist";
         line chop 0 chop 0.1 dashed from last box .nw to A.e ->;
         line chop 0 chop 0.1 dashed from last box .w  to B.e ->;
         line chop 0 chop 0.1 dashed from last box .sw to C.e ->;
     }
     .PE


Figure 20-2: Hypothetical production flow for dual-mode publishing


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