rom/graphics/areamove.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Graphics function AreaMove()
   6     Lang: english
   7 */
   8 #include <exec/types.h>
   9 #include <graphics/rastport.h>
  10 #include "graphics_intern.h"
  11 #include "gfxfuncsupport.h"
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16 #include <proto/graphics.h>
  17
  18         AROS_LH3(ULONG, AreaMove,
  19
  20 /*  SYNOPSIS */
  21         AROS_LHA(struct RastPort *, rp, A1),
  22         AROS_LHA(WORD             , x , D0),
  23         AROS_LHA(WORD             , y , D1),
  24
  25 /*  LOCATION */
  26         struct GfxBase *, GfxBase, 42, Graphics)
  27
  28 /*  FUNCTION
  29         Define a new starting point in the vector list for the following
  30         polygon defined by calls to AreaDraw(). The last polygon is closed
  31         if it wasn't closed by the user and the new starting points are
  32         added to the vector collection matrix.
  33
  34     INPUTS
  35         rp - pointer to a valid RastPort structure with a pointer to
  36              the previously initialized AreaInfo structure.
  37         x  - x-coordinate of the starting-point in the raster
  38         y  - y-coordinate of the starting-point in the raster
  39
  40     RESULT
  41         error -  0 for success
  42                 -1 if the vector collection matrix is full
  43
  44     NOTES
  45
  46     EXAMPLE
  47
  48     BUGS
  49
  50     SEE ALSO
  51         InitArea() AreaDraw() AreaEllipse() AreaCircle() graphics/rastport.h
  52
  53     INTERNALS
  54
  55     HISTORY
  56
  57 *****************************************************************************/
  58 {
  59     AROS_LIBFUNC_INIT
  60
  61     struct AreaInfo * areainfo = rp->AreaInfo;
  62
  63     /* Is there still enough storage area in the areainfo-buffer?
  64      * We just need room for one entry.
  65      */
  66
  67     if (areainfo->Count + 1 <= areainfo->MaxCount)
  68     {
  69         FIX_GFXCOORD(x);
  70         FIX_GFXCOORD(y);
  71
  72         /* is this the very first entry in the vector collection matrix */
  73         if (0 == areainfo->Count)
  74         {
  75             areainfo->FirstX = x;
  76             areainfo->FirstY = y;
  77
  78             /* Insert the new point into the matrix */
  79             areainfo->VctrPtr[0] = x;
  80             areainfo->VctrPtr[1] = y;
  81             areainfo->VctrPtr    = &areainfo->VctrPtr[2];
  82
  83             areainfo->FlagPtr[0] = AREAINFOFLAG_MOVE;
  84             areainfo->FlagPtr++;
  85
  86             areainfo->Count++;
  87         }
  88         else
  89         {
  90             /* if the previous command was also an AreaMove() then we will replace
  91              * that one ...
  92              */
  93             if ( AREAINFOFLAG_MOVE == areainfo->FlagPtr[-1])
  94             {
  95                 areainfo->FirstX = x;
  96                 areainfo->FirstY = y;
  97
  98                 /* replace the previous point */
  99                 areainfo->VctrPtr[-2] = x;
 100                 areainfo->VctrPtr[-1] = y;
 101             }
 102             else /* it's not the first command and the previous command wasn't AreaMove() */
 103             {
 104                 /* ... otherwise close the polygon if necessary */
 105
 106                 areaclosepolygon(areainfo);
 107
 108                 /* Need to check again, if there is enough room, because
 109                    areaclosepolygon might have eaten one vector!! */
 110
 111                 if (areainfo->Count + 1 > areainfo->MaxCount)
 112                     return -1;
 113
 114                 areainfo->FirstX = x;
 115                 areainfo->FirstY = y;
 116
 117                 /* Insert the new point into the matrix */
 118                 areainfo->VctrPtr[0] = x;
 119                 areainfo->VctrPtr[1] = y;
 120                 areainfo->VctrPtr    = &areainfo->VctrPtr[2];
 121
 122                 areainfo->FlagPtr[0] = AREAINFOFLAG_MOVE;
 123                 areainfo->FlagPtr++;
 124
 125                 areainfo->Count++;
 126             }
 127
 128         } /* if (0 == areainfo->Count) */
 129
 130     } /* if (areainfo->Count + 1 <= areainfo->MaxCount) */
 131     else
 132         return -1;
 133
 134     return 0;
 135
 136     AROS_LIBFUNC_EXIT
 137
 138 } /* AreaMove */