rom/graphics/scrollrasterbf.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Graphics function ScrollRasterBF()
   6     Lang: english
   7 */
   8 #include "graphics_intern.h"
   9 #include <graphics/rastport.h>
  10 #include <graphics/gfx.h>
  11 #include "gfxfuncsupport.h"
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16 #include <graphics/rastport.h>
  17 #include <proto/graphics.h>
  18
  19         AROS_LH7(void, ScrollRasterBF,
  20
  21 /*  SYNOPSIS */
  22         AROS_LHA(struct RastPort *, rp, A1),
  23         AROS_LHA(LONG             , dx, D0),
  24         AROS_LHA(LONG             , dy, D1),
  25         AROS_LHA(LONG             , xMin, D2),
  26         AROS_LHA(LONG             , yMin, D3),
  27         AROS_LHA(LONG             , xMax, D4),
  28         AROS_LHA(LONG             , yMax, D5),
  29
  30 /*  LOCATION */
  31         struct GfxBase *, GfxBase, 167, Graphics)
  32
  33 /*  FUNCTION
  34       Scroll the contents of a rastport (dx,dy) towards (0,0).
  35       The empty spaces is filled by a call to EraseRect().
  36       Only the pixel in the rectangle (xMin,yMin)-(xMax,yMax)
  37       will be affected. The lower right corner (xMax, yMax) is
  38       automatically adjusted to the lower right corner in case
  39       it would be outside.
  40       After this operation the Flags bit of the layer associated
  41       with this rastport, if there is any layer, should be tested
  42       for simple layers in case there has any damage been created.
  43
  44
  45     INPUTS
  46       rp    - pointer to rastport
  47       dx,dy - distance to move in x and y direction. Positive values go
  48               towards (0,0)
  49       xMin,yMin - upper left  hand corner of the affected rectangle
  50       xMax,yMax - lower right hand corner of the affected rectangle
  51
  52     RESULT
  53
  54     NOTES
  55
  56     EXAMPLE
  57
  58     BUGS
  59
  60     SEE ALSO
  61
  62     INTERNALS
  63
  64     HISTORY
  65
  66 *****************************************************************************/
  67 {
  68     AROS_LIBFUNC_INIT
  69     AROS_LIBBASE_EXT_DECL(struct GfxBase *,GfxBase)
  70
  71     LONG width, height, absdx, absdy;
  72
  73     FIX_GFXCOORD(xMin);
  74     FIX_GFXCOORD(yMin);
  75     FIX_GFXCOORD(xMax);
  76     FIX_GFXCOORD(yMax);
  77
  78     if ((xMin > xMax) || (yMin > yMax)) return;
  79
  80     /*
  81        This function will simply call ScrollRaster() and fill the empty
  82        space with calls to EraseRect()
  83      */
  84
  85     /*
  86        adjust xMax and yMax in case the lower right corner would be outside
  87        the rastport
  88     */
  89     /* Is it a window's rastport ? */
  90     if (NULL != rp->Layer)
  91     {
  92         struct Layer * L = rp->Layer;
  93
  94         if (xMax > (L->bounds.MaxX - L->bounds.MinX) )
  95             xMax = (L->bounds.MaxX - L->bounds.MinX) ;
  96
  97         if (yMax > (L->bounds.MaxY - L->bounds.MinY) )
  98             yMax = (L->bounds.MaxY - L->bounds.MinY) ;
  99
 100     }
 101     else
 102     {
 103         /* this one belongs to a screen */
 104         struct BitMap * bm = rp->BitMap;
 105
 106         ULONG width  = GetBitMapAttr(bm, BMA_WIDTH);
 107         ULONG height = GetBitMapAttr(bm, BMA_HEIGHT);
 108
 109         if ((ULONG)xMax >= width )
 110             xMax = width - 1;
 111
 112         if ((ULONG)yMax >= height)
 113             yMax = height - 1;
 114     }
 115
 116     absdx = (dx >= 0) ? dx : -dx;
 117     absdy = (dy >= 0) ? dy : -dy;
 118
 119     width  = xMax - xMin + 1;
 120     height = yMax - yMin + 1;
 121
 122     if ((width < 1) || (height < 1)) return;
 123
 124     if ((absdx >= width) || (absdy >= height))
 125     {
 126         EraseRect(rp, xMin, yMin, xMax, yMax);
 127         return;
 128     }
 129
 130
 131      if (FALSE == MoveRaster(rp, dx, dy, xMin, yMin, xMax, yMax, TRUE, GfxBase))
 132         return;
 133
 134     /*
 135        The raster is scrolled and I fill the empty area with the
 136        EraseRect()
 137      */
 138
 139     /* was it scrolled left or right? */
 140     if (0 != dx)
 141     {
 142         if (dx > 0)
 143         {
 144             /* scrolled towards left, clearing on the right */
 145             EraseRect(rp,
 146                       xMax - dx + 1,
 147                       yMin,
 148                       xMax,
 149                       yMax);
 150         }
 151         else
 152         {
 153             /* scrolled towards right, clearing on the left */
 154             EraseRect(rp,
 155                       xMin,
 156                       yMin,
 157                       xMin - dx - 1,  /* a scroll by -1 should only erase a row of width 1 */
 158                       yMax);
 159         }
 160     }
 161
 162     if (0 != dy)
 163     {
 164         if (dy > 0)
 165         {
 166             /* scrolled up, clearing on the bottom */
 167             EraseRect(rp,
 168                       xMin,
 169                       yMax - dy + 1,
 170                       xMax,
 171                       yMax);
 172         }
 173         else
 174         {
 175             /* scrolled down, clearing on the top */
 176             EraseRect(rp,
 177                       xMin,
 178                       yMin,
 179                       xMax,
 180                       yMin - dy - 1);
 181         }
 182     }
 183
 184
 185     AROS_LIBFUNC_EXIT
 186 } /* ScrollRasterBF */