dot matrix character RS2 JiT compiler - Dotmatrix printer driver processing
© RedTitan Technology 2012
It is difficult to recover dot matrix character images as text using OCR techniques. Discontinuities in stem thicknesses will cause recognition errors. EscapeE uses the generic scripting plugin (RS2) to provide a simple text field recovery mechanism for dot matrix text mages. This provides a fast way of reprocessing legacy applications as full text searchable PDF files (particularily using RedTitan parallel port conversion hardware applications) The typical character "black width" in dot matrix pixels is 5 and an individual character is set in 7 pixels width - the space width is 7. EscapeE scales the output to match the original printer rendition. For an EPSON printer the scale is 8.34x10. The script resamples a field image at this scale and compares individual characters to a database. e.g. The "3" character database entry.
    CHARACTER
    name=3
    value=0033
    margin-top=0
    margin-bottom=0

    -***-
    *---*
    ----*
    --**-
    ----*
    *---*
    -***-

The EscapeE EVALUATE plugin configuration dialogue includes a wizard to automatiaclly create an RS2 script that will process all defined fields using the DOTMATRIX function. e.g.
            // REDTITAN RS2 CONTROL

            // Edit below - click "add" to create prototype program statement
            // Escape scripting control generated by Evaluate wizard Thu 15-Mar-2012 10:33:00

            // Publish location of the evaluate plugin field
            fieldname:="FIELD1";
            xpos:=fieldLeft(fieldname);
            ypos:=fieldTop(fieldname);
            width:=fieldWidth(fieldname);

            function dotm(fieldname:string):string;
            begin
              lc:=[];
              L:=[];

              xpos:=fieldLeft(fieldname);
              ypos:=fieldTop(fieldname);
              w:=fieldwidth(fieldname);
              h:=fieldheight(fieldname);

              i:=dotmatrix(fieldname,"C:\Users\Pete\epson.dmb",L);

                if i=-3 then showmessage("Database not found") else
                begin
                  if i<0 then
                  showmessage("DATABASE contains unknown characters "#10"Check with DMDB "+inttostr(i)+" "+fieldname);
                end;

                assign(lc,0,w);
                th:=tab(xpos,ypos,lc,h); // single column table, same width as field

                brush(255,255,255);      // 255,255,255 is white
                box(th);                 // fill field box with colour

                font(14,"Courier","");
                text(xpos+17,ypos+100,L); // replace with recognised text
              end;

            // attempt to recognise all defined fields as dot matrix characters

            lf:=[];
            i:=fields(lf);
            for ix:=0 to pred(i) do dotm(list_strings(lf,ix));