rom/hyperlayers/scrolllayer.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc:
   6     Lang: english
   7 */
   8 #include <aros/libcall.h>
   9 #include <graphics/clip.h>
  10 #include <exec/types.h>
  11 #include <proto/exec.h>
  12 #include <graphics/layers.h>
  13 #include <proto/layers.h>
  14 #include <proto/graphics.h>
  15 #include "layers_intern.h"
  16
  17 /*****************************************************************************
  18
  19     NAME */
  20
  21         AROS_LH4(void, ScrollLayer,
  22
  23 /*  SYNOPSIS */
  24         AROS_LHA(LONG          , dummy, A0),
  25         AROS_LHA(struct Layer *, l    , A1),
  26         AROS_LHA(LONG          , dx   , D0),
  27         AROS_LHA(LONG          , dy   , D1),
  28
  29 /*  LOCATION */
  30         struct LayersBase *, LayersBase, 12, Layers)
  31
  32 /*  FUNCTION
  33         For superbitmapped layers this function work like this:.
  34         It updates the contents of the superbitmap with what is
  35         visible on the display, repositions the superbitmap
  36         and redraws the display.
  37         For non-superbitmapped layers, all subsequent (x,y) pairs
  38         are adjusted by the scroll(x,y) value in the layer. If
  39         ScrollLayer(-10,-3) was called and (0,0) is drawn it will
  40         finally end up at coordinates (10, 3) in the superbitmap.
  41
  42     INPUTS
  43         l  - pointer to layer
  44         dx - delta x to add to current x scroll value
  45         dy - delta y to add to current y scroll value
  46
  47     RESULT
  48
  49
  50     NOTES
  51
  52     EXAMPLE
  53
  54     BUGS
  55       not tested
  56
  57     SEE ALSO
  58
  59     INTERNALS
  60
  61     HISTORY
  62         27-11-96    digulla automatically created from
  63                             layers_lib.fd and clib/layers_protos.h
  64
  65 *****************************************************************************/
  66 {
  67   AROS_LIBFUNC_INIT
  68   AROS_LIBBASE_EXT_DECL(struct LayersBase *,LayersBase)
  69
  70   if (0 == dx && 0 == dy)
  71     return;
  72
  73   LockLayer(0, l);
  74
  75   /* if it's a superbitmapped layer */
  76   if ((l->Flags & LAYERSUPER) != 0)
  77   {
  78     /* store the visible "stuff" to the superbitmap */
  79     SyncSBitMap(l);
  80
  81     l->Scroll_X -= dx;
  82     l->Scroll_Y -= dy;
  83
  84     /* show what's in the superbitmap */
  85     CopySBitMap(l);
  86   }
  87   else
  88   {
  89     l->Scroll_X -= dx;
  90     l->Scroll_Y -= dy;
  91   }
  92
  93   UnlockLayer(l);
  94
  95   return;
  96
  97   AROS_LIBFUNC_EXIT
  98 } /* ScrollLayer */