rom/graphics/scrollrasterbf.c

   1 /*
   2     Copyright © 1995-2007, 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
  70     LONG width, height, absdx, absdy;
  71
  72     FIX_GFXCOORD(xMin);
  73     FIX_GFXCOORD(yMin);
  74     FIX_GFXCOORD(xMax);
  75     FIX_GFXCOORD(yMax);
  76
  77     if ((xMin > xMax) || (yMin > yMax)) return;
  78
  79     /*
  80        This function will simply call ScrollRaster() and fill the empty
  81        space with calls to EraseRect()
  82      */
  83
  84     /*
  85        adjust xMax and yMax in case the lower right corner would be outside
  86        the rastport
  87     */
  88     /* Is it a window's rastport ? */
  89     if (NULL != rp->Layer)
  90     {
  91         struct Layer * L = rp->Layer;
  92
  93         if (xMax > (L->bounds.MaxX - L->bounds.MinX) )
  94             xMax = (L->bounds.MaxX - L->bounds.MinX) ;
  95
  96         if (yMax > (L->bounds.MaxY - L->bounds.MinY) )
  97             yMax = (L->bounds.MaxY - L->bounds.MinY) ;
  98
  99     }
 100     else
 101     {
 102         /* this one belongs to a screen */
 103         struct BitMap * bm = rp->BitMap;
 104
 105         ULONG width  = GetBitMapAttr(bm, BMA_WIDTH);
 106         ULONG height = GetBitMapAttr(bm, BMA_HEIGHT);
 107
 108         if ((ULONG)xMax >= width )
 109             xMax = width - 1;
 110
 111         if ((ULONG)yMax >= height)
 112             yMax = height - 1;
 113     }
 114
 115     absdx = (dx >= 0) ? dx : -dx;
 116     absdy = (dy >= 0) ? dy : -dy;
 117
 118     width  = xMax - xMin + 1;
 119     height = yMax - yMin + 1;
 120
 121     if ((width < 1) || (height < 1)) return;
 122
 123     if ((absdx >= width) || (absdy >= height))
 124     {
 125         EraseRect(rp, xMin, yMin, xMax, yMax);
 126         return;
 127     }
 128
 129
 130      if (!MoveRaster(rp, dx, dy, xMin, yMin, xMax, yMax, TRUE, GfxBase))
 131         return;
 132
 133     /*
 134        The raster is scrolled and I fill the empty area with the
 135        EraseRect()
 136      */
 137
 138     /* was it scrolled left or right? */
 139     if (0 != dx)
 140     {
 141         if (dx > 0)
 142         {
 143             /* scrolled towards left, clearing on the right */
 144             EraseRect(rp,
 145                       xMax - dx + 1,
 146                       yMin,
 147                       xMax,
 148                       yMax);
 149         }
 150         else
 151         {
 152             /* scrolled towards right, clearing on the left */
 153             EraseRect(rp,
 154                       xMin,
 155                       yMin,
 156                       xMin - dx - 1,  /* a scroll by -1 should only erase a row of width 1 */
 157                       yMax);
 158         }
 159     }
 160
 161     if (0 != dy)
 162     {
 163         if (dy > 0)
 164         {
 165             /* scrolled up, clearing on the bottom */
 166             EraseRect(rp,
 167                       xMin,
 168                       yMax - dy + 1,
 169                       xMax,
 170                       yMax);
 171         }
 172         else
 173         {
 174             /* scrolled down, clearing on the top */
 175             EraseRect(rp,
 176                       xMin,
 177                       yMin,
 178                       xMax,
 179                       yMin - dy - 1);
 180         }
 181     }
 182
 183
 184     AROS_LIBFUNC_EXIT
 185 } /* ScrollRasterBF */