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()
  52         graphics/rastport.h
  53
  54     INTERNALS
  55
  56     HISTORY
  57
  58 *****************************************************************************/
  59 {
  60     AROS_LIBFUNC_INIT
  61
  62     struct AreaInfo * areainfo = rp->AreaInfo;
  63
  64     /* Is there still enough storage area in the areainfo-buffer?
  65      * We just need room for one entry.
  66      */
  67
  68     if (areainfo->Count + 1 <= areainfo->MaxCount)
  69     {
  70         FIX_GFXCOORD(x);
  71         FIX_GFXCOORD(y);
  72
  73         /* is this the very first entry in the vector collection matrix */
  74         if (0 == areainfo->Count)
  75         {
  76             areainfo->FirstX = x;
  77             areainfo->FirstY = y;
  78
  79             /* Insert the new point into the matrix */
  80             areainfo->VctrPtr[0] = x;
  81             areainfo->VctrPtr[1] = y;
  82             areainfo->VctrPtr    = &areainfo->VctrPtr[2];
  83
  84             areainfo->FlagPtr[0] = AREAINFOFLAG_MOVE;
  85             areainfo->FlagPtr++;
  86
  87             areainfo->Count++;
  88         }
  89         else
  90         {
  91             /* if the previous command was also an AreaMove() then we will replace
  92              * that one ...
  93              */
  94             if ( AREAINFOFLAG_MOVE == areainfo->FlagPtr[-1])
  95             {
  96                 areainfo->FirstX = x;
  97                 areainfo->FirstY = y;
  98
  99                 /* replace the previous point */
 100                 areainfo->VctrPtr[-2] = x;
 101                 areainfo->VctrPtr[-1] = y;
 102             }
 103             else /* it's not the first command and the previous command wasn't AreaMove() */
 104             {
 105                 /* ... otherwise close the polygon if necessary */
 106
 107                 areaclosepolygon(areainfo);
 108
 109                 /* Need to check again, if there is enough room, because
 110                    areaclosepolygon might have eaten one vector!! */
 111
 112                 if (areainfo->Count + 1 > areainfo->MaxCount)
 113                     return -1;
 114
 115                 areainfo->FirstX = x;
 116                 areainfo->FirstY = y;
 117
 118                 /* Insert the new point into the matrix */
 119                 areainfo->VctrPtr[0] = x;
 120                 areainfo->VctrPtr[1] = y;
 121                 areainfo->VctrPtr    = &areainfo->VctrPtr[2];
 122
 123                 areainfo->FlagPtr[0] = AREAINFOFLAG_MOVE;
 124                 areainfo->FlagPtr++;
 125
 126                 areainfo->Count++;
 127             }
 128
 129         } /* if (0 == areainfo->Count) */
 130
 131     } /* if (areainfo->Count + 1 <= areainfo->MaxCount) */
 132     else
 133         return -1;
 134
 135     return 0;
 136
 137     AROS_LIBFUNC_EXIT
 138
 139 } /* AreaMove */