rom/hyperlayers/installlayerinfohook.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc:
   6     Lang: english
   7 */
   8 #include <aros/libcall.h>
   9
  10 #define DEBUG 0
  11 #include <aros/debug.h>
  12 #undef kprintf
  13
  14 /*****************************************************************************
  15
  16     NAME */
  17 #include <proto/layers.h>
  18 #include "layers_intern.h"
  19 #include "basicfuncs.h"
  20
  21         AROS_LH2(struct Hook *, InstallLayerInfoHook,
  22
  23 /*  SYNOPSIS */
  24         AROS_LHA(struct Layer_Info *, li, A0),
  25         AROS_LHA(struct Hook       *, hook, A1),
  26
  27 /*  LOCATION */
  28         struct LayersBase *, LayersBase, 34, Layers)
  29
  30 /*  FUNCTION
  31         Install a backfill hook into the LayerInfo structure. This
  32         backfill hook will be called to clear the areas where there
  33         is no layer. It will be used for every layer.
  34
  35     INPUTS
  36         li - pointer to layer info
  37
  38     RESULT
  39         If there was a backfill hook installed before it will be
  40         returned. LAYERS_BACKFILL will be returned if the default
  41         backfill hook was installed, LAYERS_NOBACKFILL if there
  42         was nothing to be called for clearing an area.
  43
  44     NOTES
  45         The hook is not called immediately. It will be called for
  46         those areas that have to be cleared when layers move away
  47         from those areas.
  48
  49     EXAMPLE
  50
  51     BUGS
  52
  53     SEE ALSO
  54
  55     INTERNALS
  56
  57     HISTORY
  58         27-11-96    digulla automatically created from
  59                             layers_lib.fd and clib/layers_protos.h
  60
  61 *****************************************************************************/
  62 {
  63     AROS_LIBFUNC_INIT
  64
  65     struct Hook *OldHook;
  66
  67     D(bug("InstallLayerInfoHook(li @ $%lx, hook @ $%lx)\n", li, hook));
  68
  69     LockLayerInfo(li);
  70
  71     OldHook = li->BlankHook;
  72
  73     li->BlankHook = hook;
  74
  75     if (li->check_lp)
  76     {
  77         LockLayer(0, li->check_lp);
  78         li->check_lp->BackFill = hook;
  79         UnlockLayer(li->check_lp);
  80     }
  81
  82     UnlockLayerInfo(li);
  83
  84     return OldHook;
  85
  86     AROS_LIBFUNC_EXIT
  87 } /* InstallLayerInfoHook */