dib24bppc.c

这是一个开放源代码的与WINNT/WIN2K/WIN2003兼容的操作系统

/*
 *  ReactOS W32 Subsystem
 *  Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003 ReactOS Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
/* $Id: dib24bppc.c 23732 2006-08-26 23:26:39Z greatlrd $ */

#include <w32k.h>

#define NDEBUG
#include <debug.h>

VOID
DIB_24BPP_HLine(SURFOBJ *SurfObj, LONG x1, LONG x2, LONG y, ULONG c)
{
  PBYTE addr = (PBYTE)SurfObj->pvScan0 + y * SurfObj->lDelta + (x1 << 1) + x1;
  ULONG Count = x2 - x1;


  if (Count < 8)
    {
      /* For small fills, don't bother doing anything fancy */
      while (Count--)
        {
          *(PUSHORT)(addr) = c;
          addr += 2;
          *(addr) = c >> 16;
          addr += 1;
        }
    }
  else
    {
      /* Align to 4-byte address */
      while (0 != ((ULONG_PTR) addr & 0x3))
        {
          *(PUSHORT)(addr) = c;
          addr += 2;
          *(addr) = c >> 16;
          addr += 1;
          Count--;
        }
      /* If the color we need to fill with is 0ABC, then the final mem pattern
       * (note little-endianness) would be:
       *
       * |C.B.A|C.B.A|C.B.A|C.B.A|   <- pixel borders
       * |C.B.A.C|B.A.C.B|A.C.B.A|   <- ULONG borders
       *
       * So, taking endianness into account again, we need to fill with these
       * ULONGs: CABC BCAB ABCA */

      c = c & 0xffffff;                /* 0ABC */
      Fill[0] = c | (c << 24);         /* CABC */
      Fill[1] = (c >> 8) | (c << 16);  /* BCAB */
      Fill[2] = (c << 8) | (c >> 16);  /* ABCA */
      MultiCount = Count / 4;
      do
        {
          *(PULONG)addr = Fill[0];
          addr += 4;
          *(PULONG)addr = Fill[1];
          addr += 4;
          *(PULONG)addr = Fill[2];
          addr += 4;
        }
      while (0 != --MultiCount);

      Count = Count & 0x03;
      while (0 != Count--)
        {
          *(PUSHORT)(addr) = c;
          addr += 2;
          *(addr) = c >> 16;
          addr += 1;
        }
    }
}