Topspeed_JPI/TS-V3/SRC/GRAPHI.LST

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    1  (* Release 3.10 *)
    2  (*-------------------------------------------------------------------------*
    3  *                                                                          *
    4  *  GRAPHI.MOD - OS/2 graphics functions requiring IOPL                     *
    5  *                                                                          *
    6  *  COPYRIGHT (C) 1987..1992 Clarion Software Corporation.                  *
    7  *  All Rights Reserved                                                     *
    8  *                                                                          *
    9  *--------------------------------------------------------------------------*)
   10  
   11  (*# call(o_a_copy=>off) *)
   12  (*# module(implementation=>off) *)
   13  (*%F _fdata *)
   14  (*# data(seg_name => null) *)
   15  (*%E *)
   16  (*# check(stack=>off,
   17            index=>off,
   18            range=>off,
   19            overflow=>off,
   20            nil_ptr=>off) *)
   21  
   22  IMPLEMENTATION MODULE GraphI;
   23  
   24  (*# call(near_call=>off,
   25           seg_name=>GRAPH_IOPL,
   26           iopl=>on) *)
   27  
   28  IMPORT Graph, Dos;
   29  
   30  CONST
   31    CGAWidth           = 320 ;
   32    CGADepth           = 200 ;
   33    CGANumColor        = 4 ;
   34    EGAWidth           = 640 ;
   35    EGADepth           = 350 ;
   36    VGAWidth           = 640 ;
   37    VGADepth           = 350 ;
   38    EGANumColor        = 16 ;
   39    VGA256Width        = 320 ;
   40    VGA256Depth        = 200 ;
   41    VGANumColor        = 16 ;
   42  
   43  CONST
   44    HercWidth          = 720 ;
   45    HercDepth          = 348 ;
   46    HercNumColor       = 2 ;
   47    ATTWidth           = 640 ;
   48    ATTDepth           = 400 ;
   49    ATTNumColor        = 2 ;
   50  
   51  
   52  PROCEDURE SaveScreen;
   53  VAR
   54    BitMap : CARDINAL;
   55    bp : CGABuffPtr;
*****         ^ undeclared identifier
   56  BEGIN
   57    IF IsCGA THEN
*****       ^ undeclared identifier
   58      bp := FarADR(CBuffer);
*****      ^ not supported yet
*****            ^ undeclared identifier
*****                   ^ undeclared identifier
   59      GRCopy(bp, [VideoSel:0 CGABuffPtr], 4000H);
*****      ^ undeclared identifier
*****             ^ not supported yet
*****                  ^ undeclared identifier
*****                           ^ not supported yet
*****                                               ^ not supported yet
   60    ELSE
   61      FOR BitMap := 0 TO MaxBitMap DO
*****                         ^ undeclared identifier
   62        Out(3CEH,4);
*****        ^ undeclared identifier
*****                  ^ not supported yet
   63        Out(3CFH,SHORTCARD(BitMap));
*****        ^ undeclared identifier
*****                                 ^ not supported yet
   64        GRCopy(Buffer[BitMap], [VideoSel:0 BMP], BitMapSize);
*****        ^ undeclared identifier
*****               ^ undeclared identifier
*****                            ^ not supported yet
*****                                ^ undeclared identifier
*****                                         ^ not supported yet
*****                                                 ^ undeclared identifier
   65      END;
   66    END;
   67  END SaveScreen;
*****      ^ not supported yet
   68  
   69  
   70  PROCEDURE RestoreScreen();
   71  VAR
   72    BitMap      : CARDINAL;
   73  BEGIN
   74    IF IsCGA THEN
*****       ^ undeclared identifier
   75      GRCopy([VideoSel:0 CGABuffPtr], FarADR(CBuffer), 4000H);
*****      ^ undeclared identifier
*****              ^ undeclared identifier
*****                       ^ not supported yet
*****                                      ^ undeclared identifier
*****                                             ^ undeclared identifier
*****                                                            ^ not supported yet
   76    ELSE
   77      FOR BitMap := 0 TO MaxBitMap DO
*****                         ^ undeclared identifier
   78        Out( 3C4H,2);Out( 3C5H,SHORTCARD(1<<BitMap));
*****        ^ undeclared identifier
*****                   ^ not supported yet
*****                     ^ undeclared identifier
*****                                                  ^ not supported yet
   79        GRCopy([VideoSel:0 BMP], Buffer[BitMap], BitMapSize);
*****        ^ undeclared identifier
*****                ^ undeclared identifier
*****                         ^ not supported yet
*****                                 ^ undeclared identifier
*****                                              ^ not supported yet
*****                                                 ^ undeclared identifier
   80      END;
   81    END ;
   82  END RestoreScreen;
*****      ^ not supported yet
   83  
   84  
   85  PROCEDURE EGAPlot( x,y,c : CARDINAL); (* Also VGA *)
   86  VAR
   87  (*# save, data(volatile=>on) *)
   88    t:BS;
*****      ^ undeclared identifier
   89  (*# restore *)
   90    p,b,s,i,bi:CARDINAL;
   91  BEGIN
   92     IF (x < EGAWidth) AND (y < Graph.Depth) THEN
*****                                ^ not supported yet
*****                                      ^ not supported yet
   93        bi := (7-(x MOD 8));
   94        p := y*80+(x DIV 8);
   95        IF Virtual THEN
*****           ^ undeclared identifier
   96          FOR i := 0 TO 3 DO
   97            IF i IN BS(c) THEN
*****                    ^ undeclared identifier
*****                        ^ not supported yet
   98              INCL(BS(Buffer[i]^[p]),bi)
*****              ^ undeclared identifier
*****                   ^ undeclared identifier
*****                      ^ undeclared identifier
*****                              ^ not supported yet
*****                                  ^ not supported yet
*****                                       ^ not supported yet
   99            ELSE
  100              EXCL(BS(Buffer[i]^[p]),bi);
*****              ^ undeclared identifier
*****                   ^ undeclared identifier
*****                      ^ undeclared identifier
*****                              ^ not supported yet
*****                                  ^ not supported yet
*****                                       ^ not supported yet
  101            END;
  102          END;
  103        ELSE
  104          b := 1 << bi;
  105  
  106          Out( 3CEH,8);Out( 3CFH,SHORTCARD(b));
*****          ^ undeclared identifier
*****                     ^ not supported yet
*****                       ^ undeclared identifier
*****                                            ^ not supported yet
  107          Out( 3C4H,2);Out( 3C5H,0FH);
*****          ^ undeclared identifier
*****                     ^ not supported yet
*****                       ^ undeclared identifier
*****                                    ^ not supported yet
  108          s := VideoSel;
*****               ^ undeclared identifier
  109          t := [s:p BP]^;
*****          ^ not supported yet
*****                  ^ not supported yet
*****                       ^ not supported yet
  110          [s:p BP]^ := BS{};
  111          Out( 3C4H,2);Out( 3C5H,SHORTCARD(c));
  112          [s:p BP]^ := BS{0..7};
  113          Out( 3CEH,8);Out( 3CFH,0FFH);
  114          Out( 3C4H,2);Out( 3C5H,0FH);
  115  
  116        END;
  117     END;
  118  END EGAPlot;
  119  
  120  PROCEDURE EGAPoint(x,y:CARDINAL) : CARDINAL; (* Also VGA *)
  121  VAR
  122    t:BS;
  123    p,b,s,i:CARDINAL;
  124    c:CARDINAL;
  125  BEGIN
  126    c := 0;
  127    IF (x < EGAWidth) AND (y < Graph.Depth) THEN
  128      b := 1 << (7-(x MOD 8));
  129      p := y*80+(x DIV 8  );
  130  
  131      IF Virtual THEN
  132        FOR i := 3 TO 0 BY -1 DO
  133          t := BS(Buffer[i]^[p])*BS(b);
  134          c := c * 2 + CARDINAL( SHORTCARD(t) );
  135        END;
  136      ELSE
  137        s := VideoSel;
  138  
  139        Out( 3CEH, 4 ); (* read map sel *)
  140  
  141        Out( 3CFH, 3 );
  142        t := [s:p BP]^;
  143        t := t * BS(b);
  144        c := CARDINAL( SHORTCARD(t) );
  145  
  146        Out( 3CFH, 2 );
  147        t := [s:p BP]^;
  148        t := t * BS(b);
  149        c := c * 2 + CARDINAL( SHORTCARD(t) );
  150  
  151        Out( 3CFH, 1 );
  152        t := [s:p BP]^;
  153        t := t * BS(b);
  154        c := c * 2 + CARDINAL( SHORTCARD(t) );
  155  
  156        Out( 3CFH, 0 );
  157        t := [s:p BP]^;
  158        t := t * BS(b);
  159        c := c * 2 + CARDINAL( SHORTCARD(t) );
  160  
  161      END;
  162      c := c >> ( 7 - ( x MOD 8 ) );
  163    END;
  164    RETURN c;
  165  END EGAPoint;
  166  
  167  PROCEDURE EGAHLine ( x,y,x2 : CARDINAL; c:CARDINAL ); (* Also VGA *)
  168  VAR c1,c2,i : CARDINAL;
  169  BEGIN
  170    IF y >= Graph.Depth THEN RETURN END;
  171    IF INTEGER(x) >= INTEGER(EGAWidth) THEN RETURN END;
  172    IF INTEGER(x) < 0 THEN x := 0; END;
  173    IF x2 >= EGAWidth THEN x2 := EGAWidth-1 END;
  174    WHILE (x MOD 8 # 0)  AND (x <= x2) DO
  175      EGAPlot( x  , y , c ); INC( x  );
  176    END;
  177    WHILE (x2 MOD 8 # 7) AND (x <= x2) DO
  178      EGAPlot( x2 , y , c ); DEC( x2 );
  179    END;
  180    IF INTEGER(x) > INTEGER(x2) THEN RETURN; END;
  181    y := y*80;
  182    x := x DIV 8;
  183    x2 := x2 DIV 8;
  184    IF Virtual THEN
  185      INC(y,x);
  186      WHILE x <= x2 DO
  187        FOR i := 0 TO 3 DO
  188            IF i IN BS(c) THEN
  189            Buffer[i]^[y] := BS{0..7};
  190          ELSE
  191            Buffer[i]^[y] := BS{};
  192          END;
  193        END;
  194        INC( x );
  195        INC( y );
  196      END;
  197    ELSE
  198      Out( 3CEH,8);Out( 3CFH,0FFH);
  199      Out( 3C4H,2);Out( 3C5H,0FH);
  200      Out( 3CEH,5);Out( 3CFH,2);
  201      WHILE x <= x2 DO
  202        [VideoSel:y+x BP]^ := BS(c);
  203        INC( x );
  204      END;
  205    END ;
  206    Out( 3CEH,5);Out( 3CFH,0);
  207  END EGAHLine;
  208  
  209  (* -- CGA routines -- *)
  210  
  211  PROCEDURE SaveCGAScreen;
  212  BEGIN
  213      GRCopy([VideoSel:0 CGABuffPtr], FarADR(CBuffer), 4000H);
  214  END SaveCGAScreen;
  215  
  216  
  217  PROCEDURE RestoreCGAScreen();
  218  VAR
  219    bp : CGABuffPtr;
  220  BEGIN
  221    bp := FarADR(CBuffer);
  222    GRCopy(bp, [VideoSel:0 CGABuffPtr], 4000H);
  223  END RestoreCGAScreen;
  224  
  225  
  226  PROCEDURE CGAPlot(x,y:CARDINAL;c:CARDINAL);
  227  VAR
  228    off : CARDINAL;
  229    seg : CARDINAL;
  230    tmp : CARDINAL;
  231  BEGIN
  232    IF (x >= CGAWidth) OR (y >= CGADepth) THEN RETURN END;
  233    off := x >> 2;
  234    IF ODD(y) THEN INC( off, 2000H - 40 ) END;
  235    INC( y, y << 2 );
  236    INC( off, y << 3 );
  237    x := 3 - CARDINAL( BITSET(x) * BITSET(3) );
  238    x := x << 1;
  239    seg := VideoSel;
  240    [seg:off BP]^ := ( [seg:off BP]^ - BS(3<<x) ) + BS(c<<x);
  241  END CGAPlot;
  242  
  243  PROCEDURE CGAPoint(x,y:CARDINAL) : CARDINAL;
  244  VAR
  245    off : CARDINAL;
  246    seg : CARDINAL;
  247    tmp : CARDINAL;
  248  BEGIN
  249    IF (x >= CGAWidth) OR (y >= CGADepth) THEN RETURN MAX(CARDINAL) END;
  250    off := x >> 2;
  251    IF ODD(y) THEN INC( off, 2000H - 40 ) END;
  252    INC( y, y << 2 );
  253    INC( off, y << 3 );
  254    x := 3 - CARDINAL( BITSET(x) * BITSET(3) );
  255    x := x << 1;
  256    seg := VideoSel;
  257    RETURN CARDINAL( [seg:off BP]^ * BS(3<<x) ) >> x;
  258  END CGAPoint;
  259  
  260  PROCEDURE CGAHLine ( x,y,x2 : CARDINAL; c:CARDINAL );
  261  VAR
  262    off  : CARDINAL;
  263    seg  : CARDINAL;
  264    tmp  : CARDINAL;
  265    n,i  : CARDINAL;
  266    w    : BS;
  267    mask : BS;
  268    fillc: SHORTCARD;
  269  BEGIN
  270    IF y > CGADepth-1 THEN RETURN END;
  271    IF INTEGER(x) >= INTEGER(CGAWidth) THEN RETURN END;
  272    IF INTEGER(x) < 0 THEN x := 0; END;
  273    IF x2 >= CGAWidth THEN x2 := CGAWidth-1 END;
  274  
  275    n := ( x2 - x ) + 1;
  276    off := x >> 2;
  277    IF ODD(y) THEN
  278      INC( off, 2000H - 40 );
  279      c := ( c >> 2 + c << 2 ) MOD 16;
  280    END;
  281    c := c + c * 16;
  282    INC( y, y << 2 );
  283    INC( off, y << 3 );
  284    x := 3 - CARDINAL( BITSET(x) * BITSET(3) );
  285    x := x << 1;
  286    seg := VideoSel;
  287  
  288    w := [seg:off BP]^;
  289    REPEAT
  290      mask := BS(3 << x);
  291      w := ( w - mask ) + BS(c)*mask;
  292      DEC(n);
  293      DEC(x,2);
  294    UNTIL (n=0) OR (x=CARDINAL(-2));
  295    [seg:off BP]^ := w;
  296  
  297    INC(off);
  298    FOR i := 1 TO (n>>2) DO
  299      [seg:off BP]^ := BS(c);
  300      INC(off);
  301    END;
  302    n := n MOD 4;
  303    x := 6;
  304    w := [seg:off BP]^;
  305    WHILE n <> 0 DO
  306      mask := BS(3 << x);
  307      w := ( w - mask ) + BS(c)*mask;
  308      DEC(n);
  309      DEC(x,2);
  310    END;
  311    [seg:off BP]^ := w;
  312  END CGAHLine;
  313  
  314  PROCEDURE Plot( x,y,c : CARDINAL); (* CGA/EGA/VGA *)
  315  BEGIN
  316    IF IsCGA THEN
  317      CGAPlot(x,y,c);
  318    ELSE
  319      EGAPlot(x,y,c);
  320    END;
  321  END Plot;
  322  
  323  
  324  PROCEDURE HLine ( x,y,x2 : CARDINAL; c:CARDINAL ); (* CGA/EGA/VGA *)
  325  BEGIN
  326    IF IsCGA THEN
  327      CGAHLine(x,y,x2,c);
  328    ELSE
  329      EGAHLine(x,y,x2,c);
  330    END;
  331  END HLine;
  332  
  333  
  334  PROCEDURE Line(x1,y1,x2,y2: CARDINAL; c: CARDINAL);
  335  VAR
  336    dx,dy,e,tmp : INTEGER;
  337  BEGIN
  338    IF x1 > x2 THEN (* ensure that x2 >= x1 *)
  339      tmp := x1; x1 := x2; x2 := tmp;
  340      tmp := y1; y1 := y2; y2 := tmp;
  341    END;
  342  
  343    dx := x2-x1;
  344    e  := 0;
  345    IF y1 <= y2 THEN (* case where y increases *)
  346      dy := (y2-y1);
  347      IF dx >= dy THEN
  348        LOOP
  349          Plot( x1,y1,c );
  350          IF x1 = x2 THEN EXIT END;
  351          INC(x1);
  352          INC(e,dy);
  353          INC(e,dy);
  354          IF e > dx THEN
  355            DEC(e,dx);
  356            DEC(e,dx);
  357            INC(y1);
  358          END;
  359        END;
  360      ELSE
  361        LOOP
  362          Plot( x1,y1,c );
  363          IF y1 = y2 THEN EXIT END;
  364          INC(y1);
  365          INC(e,dx);
  366          INC(e,dx);
  367          IF e > dy THEN
  368            DEC(e,dy);
  369            DEC(e,dy);
  370            INC(x1);
  371          END;
  372        END;
  373      END;
  374    ELSE
  375      (* case where y decreases *)
  376      dy := (y1-y2);
  377      IF dx >= dy THEN
  378        LOOP
  379          Plot( x1,y1,c );
  380          IF x1 = x2 THEN EXIT END;
  381          INC(x1);
  382          INC(e,dy);
  383          INC(e,dy);
  384          IF e > dx THEN
  385            DEC(e,dx);
  386            DEC(e,dx);
  387            DEC(y1);
  388          END;
  389        END;
  390      ELSE
  391        LOOP
  392          Plot( x1,y1,c );
  393          IF y1 = y2 THEN EXIT END;
  394          DEC(y1);
  395          INC(e,dx);
  396          INC(e,dx);
  397          IF e > dy THEN
  398            DEC(e,dy);
  399            DEC(e,dy);
  400            INC(x1);
  401          END;
  402        END;
  403      END;
  404    END;
  405  END Line;
  406  
  407  
  408  CONST
  409    dx = 2;
  410    dy = 2;
  411  
  412  PROCEDURE Disc(x0,y0,r: CARDINAL; c: CARDINAL);
  413  VAR
  414    e   : INTEGER;
  415    x,y : CARDINAL;
  416  BEGIN
  417    x := r; y := 0; e := 0;
  418    WHILE INTEGER(y) <= INTEGER(x) DO
  419      HLine(x0-x,y0+y,x0+x,c);
  420      HLine(x0-x,y0-y,x0+x,c);
  421      INC(y);
  422      INC(e,y*dy-1);
  423      IF e > INTEGER(x) THEN
  424        DEC(x);
  425        DEC(e,x*dx+1);
  426        HLine(x0-y,y0+x,x0+y,c);
  427        HLine(x0-y,y0-x,x0+y,c);
  428      END;
  429    END;
  430  END Disc;
  431  
  432  PROCEDURE Circle(x0,y0,r: CARDINAL; c: CARDINAL);
  433  VAR
  434    e   : INTEGER;
  435    x,y : CARDINAL;
  436  BEGIN
  437    x := r; y := 0; e := 0;
  438    WHILE INTEGER(y) <= INTEGER(x) DO
  439      Plot(x0+x,y0+y,c);
  440      Plot(x0-x,y0+y,c);
  441      Plot(x0+x,y0-y,c);
  442      Plot(x0-x,y0-y,c);
  443      Plot(x0+y,y0+x,c);
  444      Plot(x0-y,y0+x,c);
  445      Plot(x0+y,y0-x,c);
  446      Plot(x0-y,y0-x,c);
  447      INC(y);
  448      INC(e,y*dy-1);
  449      IF e > INTEGER(x) THEN
  450        DEC(x);
  451        DEC(e,x*dx+1);
  452      END;
  453    END;
  454  END Circle;
  455  
  456  PROCEDURE Ellipse ( x0,y0 : CARDINAL ;  (* center *)
  457                      a0,b0 : CARDINAL ;  (* semi-axes *)
  458                      c     : CARDINAL ;  (* color *)
  459                      fill  : BOOLEAN ) ; (* wether filled *)
  460  VAR
  461    x,y : CARDINAL ;
  462    a,b : LONGINT ;
  463    asq,asq2,bsq,bsq2 : LONGINT ;
  464    d,dx,dy           : LONGINT ;
  465  BEGIN
  466    x := 0 ;
  467    y := b0 ;
  468    a := LONGINT(a0) ;
  469    b := LONGINT(b0) ;
  470    asq := a*a ;
  471    asq2 := asq*2 ;
  472    bsq := b*b ;
  473    bsq2 := bsq*2 ;
  474    d := bsq-(asq*b)+(asq DIV 4) ;
  475    dx := 0 ;
  476    dy := asq2*b ;
  477    WHILE dx<dy DO
  478      IF fill THEN
  479        HLine(x0-x,y0+y,x0+x,c);
  480        HLine(x0-x,y0-y,x0+x,c);
  481      ELSE
  482        Plot(x0+x,y0+y,c) ;
  483        Plot(x0-x,y0+y,c) ;
  484        Plot(x0+x,y0-y,c) ;
  485        Plot(x0-x,y0-y,c) ;
  486      END ;
  487      IF d>0 THEN
  488        DEC(y) ;
  489        DEC(dy,asq2) ;
  490        DEC(d,dy) ;
  491      END ;
  492      INC(x) ;
  493      INC(dx,bsq2) ;
  494      INC(d,bsq+dx) ;
  495    END ;
  496    INC(d,(3*(asq-bsq)DIV 2-(dx+dy))DIV 2) ;
  497    WHILE INTEGER(y)>=0 DO
  498      IF fill THEN
  499        HLine(x0-x,y0+y,x0+x,c);
  500        HLine(x0-x,y0-y,x0+x,c);
  501      ELSE
  502        Plot(x0+x,y0+y,c) ;
  503        Plot(x0-x,y0+y,c) ;
  504        Plot(x0+x,y0-y,c) ;
  505        Plot(x0-x,y0-y,c) ;
  506      END ;
  507      IF d<0 THEN
  508        INC(x) ;
  509        INC(dx,bsq2) ;
  510        INC(d,dx) ;
  511      END ;
  512      DEC(y) ;
  513      DEC(dy,asq2) ;
  514      INC(d,asq-dy) ;
  515    END ;
  516  END Ellipse ;
  517  
  518  
  519  PROCEDURE Polygon(n: CARDINAL; px,py: ARRAY OF CARDINAL; c: CARDINAL);
  520  CONST
  521    MaxPts = 20;
  522  VAR
  523    y,miny,maxy,x0,y0,x1,y1,temp,i,edge,next_edge,active : INTEGER;
  524    xord : ARRAY [0..MaxPts] OF INTEGER;
  525    x    : ARRAY [0..MaxPts] OF CARDINAL;
  526    e    : ARRAY [0..MaxPts] OF INTEGER;
  527  
  528  (*# save *)
  529  (*# call(reg_saved=>(ax,bx,cx,ds,si,di,st1,st2)) *)
  530  PROCEDURE quicksort(l,r: INTEGER);
  531  VAR
  532    i,j,temp : INTEGER;
  533    key : CARDINAL;
  534  BEGIN
  535    WHILE ( l < r ) DO
  536      i := l; j := r; key := x[xord[j]];
  537      REPEAT
  538        WHILE ( i < j ) AND ( x[xord[i]] <= key ) DO i := i + 1 END;
  539        WHILE ( i < j ) AND ( key <= x[xord[j]] ) DO j := j - 1 END;
  540        IF i < j THEN
  541          temp := xord[i]; xord[i] := xord[j]; xord[j] := temp;
  542        END;
  543      UNTIL ( i >= j );
  544      temp := xord[i]; xord[i] := xord[r]; xord[r] := temp;
  545      IF (i-l < r-i) THEN
  546        quicksort( l, i-1 ); l := i+1;
  547      ELSE
  548        quicksort( i+1, r ); r := i-1;
  549      END;
  550    END;
  551  END quicksort;
  552  (*# restore *)
  553  
  554  BEGIN
  555    IF n > MaxPts THEN n := MaxPts END;
  556  
  557    (* find extremal y points *)
  558    miny := py[0]; maxy := miny;
  559    FOR i := 0 TO n-1 DO
  560      IF INTEGER(py[i]) < miny THEN miny := py[i]; END;
  561      IF INTEGER(py[i]) > maxy THEN maxy := py[i]; END;
  562    END;
  563  
  564    FOR y := miny TO maxy DO
  565      active := -1;
  566      FOR edge := 0 TO n-1 DO
  567        IF edge = INTEGER(n-1) THEN next_edge := 0 ELSE next_edge := edge + 1; END;
  568        x0 := px[edge]; y0 := py[edge];
  569        x1 := px[next_edge]; y1 := py[next_edge];
  570        IF y0 > y1 THEN temp := x0; x0 := x1; x1 := temp;
  571                        temp := y0; y0 := y1; y1 := temp END;
  572        IF y = y0 THEN e[edge] :=  0; x[edge] := x0
  573        ELSIF ( y0 <= y ) AND ( y <= y1 ) THEN
  574          IF x1 >= x0 THEN (* x increases with y *)
  575            INC( e[edge], 2*(x1-x0) );
  576            WHILE e[edge] > INTEGER(y1-y0) DO
  577              DEC( e[edge], 2*(y1-y0) ); INC(x[edge]);
  578            END;
  579          ELSE (* x decreases with y *)
  580            INC( e[edge], 2*(x0-x1) );
  581            WHILE e[edge] > INTEGER(y1-y0) DO
  582              DEC( e[edge], 2*(y1-y0) ); DEC(x[edge]);
  583            END;
  584          END;
  585          active := active + 1;
  586          xord[active] := edge;
  587        END;
  588      END;
  589      quicksort(0,active);
  590      i := 0;
  591      WHILE i < active DO
  592        HLine( x[xord[i]], y, x[xord[i+1]], c );
  593        i := i + 2;
  594      END;
  595    END; (* for y := .. *)
  596  END Polygon;
  597  
  598  BEGIN
  599    Dos.PortAccess(0, 0, 3C4H, 3C5H);
  600    Dos.PortAccess(0, 0, 3CEH, 3CFH);
  601  END GraphI.

   71 errors