rom/graphics/clearregionregionnd.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Graphics function AndRegionRegion()
   6     Lang: english
   7 */
   8
   9 #include <graphics/regions.h>
  10
  11 #include "graphics_intern.h"
  12 #include "intregions.h"
  13
  14 /*****************************************************************************
  15
  16     NAME */
  17 #include <proto/graphics.h>
  18
  19         AROS_LH2(struct Region *, ClearRegionRegionND,
  20
  21 /*  SYNOPSIS */
  22         AROS_LHA(struct Region *, R1, A0),
  23         AROS_LHA(struct Region *, R2, A1),
  24
  25 /*  LOCATION */
  26         struct GfxBase *, GfxBase, 193, Graphics)
  27
  28 /*  FUNCTION
  29         Clear the given Region region1 from the given Region region2.
  30
  31     INPUTS
  32         region1 - pointer to a region structure
  33         region2 - pointer to a region structure
  34
  35     RESULT
  36         The resulting region or NULL in case there's no enough free memory
  37
  38     NOTES
  39
  40     EXAMPLE
  41
  42     BUGS
  43
  44     SEE ALSO
  45         XorRegionRegion(), OrRegionRegion()
  46
  47     INTERNALS
  48
  49     HISTORY
  50
  51 *****************************************************************************/
  52 {
  53     AROS_LIBFUNC_INIT
  54
  55     struct Region *R3 = NewRegion();
  56
  57     if (!R3)
  58     {
  59         /* Out of memory, failed */
  60         return NULL;
  61     }
  62
  63     if (!R2->RegionRectangle)
  64     {
  65         /* R2 is already empty, nothing to clear */
  66         return R3;
  67     }
  68
  69     if (!R1->RegionRectangle            ||
  70         !overlap(R1->bounds, R2->bounds))
  71     {
  72         /* R2 is not empty, but there's nothing to clear. Make a plain copy. */
  73         if (_CopyRegionRectangles(R2, R3, GfxBase))
  74             return R3;
  75     }
  76     else
  77     {
  78         /* Some other case, do the complete algorighm */
  79         if (_DoOperationBandBand(_ClearBandBand,
  80                                   MinX(R1), MinX(R2), MinY(R1), MinY(R2),
  81                                   R1->RegionRectangle, R2->RegionRectangle, &R3->RegionRectangle, &R3->bounds, GfxBase))
  82         {
  83             _TranslateRegionRectangles(R3->RegionRectangle, -MinX(R3), -MinY(R3));
  84             return R3;
  85         }
  86     }
  87
  88     DisposeRegion(R3);
  89     return NULL;
  90
  91     AROS_LIBFUNC_EXIT
  92 }