dib16bpp.c

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/*
 * PROJECT:         Win32 subsystem
 * LICENSE:         See COPYING in the top level directory
 * FILE:            win32ss/gdi/dib/dib16bpp.c
 * PURPOSE:         Device Independant Bitmap functions, 16bpp
 * PROGRAMMERS:     Jason Filby
 *                  Thomas Bluemel
 *                  Gregor Anich
 */

#include <win32k.h>

#define NDEBUG
#include <debug.h>

VOID
DIB_16BPP_PutPixel(SURFOBJ *SurfObj, LONG x, LONG y, ULONG c)
{
  PBYTE byteaddr = (PBYTE)SurfObj->pvScan0 + y * SurfObj->lDelta;
  PWORD addr = (PWORD)byteaddr + x;

  *addr = (WORD)c;
}

ULONG
DIB_16BPP_GetPixel(SURFOBJ *SurfObj, LONG x, LONG y)
{
  PBYTE byteaddr = (PBYTE)SurfObj->pvScan0 + y * SurfObj->lDelta;
  PWORD addr = (PWORD)byteaddr + x;
  return (ULONG)(*addr);
}

VOID
DIB_16BPP_HLine(SURFOBJ *SurfObj, LONG x1, LONG x2, LONG y, ULONG c)
{
  PDWORD addr = (PDWORD)((PWORD)((PBYTE)SurfObj->pvScan0 + y * SurfObj->lDelta) + x1);

#if defined(_M_IX86) && !defined(_MSC_VER)
  /* This is about 10% faster than the generic C code below */
  LONG Count = x2 - x1;

  __asm__ __volatile__ (
    "  cld\n"
    "  mov  %0, %%eax\n"
    "  shl  $16, %%eax\n"
    "  andl $0xffff, %0\n"  /* If the pixel value is "abcd", put "abcdabcd" in %eax */
    "  or   %0, %%eax\n"
    "  mov  %2, %%edi\n"
    "  test $0x03, %%edi\n" /* Align to fullword boundary */
    "  jz   0f\n"
    "  stosw\n"
    "  dec  %1\n"
    "  jz   1f\n"
    "0:\n"
    "  mov  %1,%%ecx\n"     /* Setup count of fullwords to fill */
    "  shr  $1,%%ecx\n"
    "  rep stosl\n"         /* The actual fill */
    "  test $0x01, %1\n"    /* One left to do at the right side? */
    "  jz   1f\n"
    "  stosw\n"
    "1:\n"
    : /* no output */
  : "r"(c), "r"(Count), "m"(addr)
    : "%eax", "%ecx", "%edi");
#else /* _M_IX86 */
  LONG cx = x1;
  DWORD cc;

  if (0 != (cx & 0x01))
  {
    *((PWORD) addr) = (WORD)c;
    cx++;
    addr = (PDWORD)((PWORD)(addr) + 1);
  }
  cc = ((c & 0xffff) << 16) | (c & 0xffff);
  while(cx + 1 < x2)
  {
    *addr++ = cc;
    cx += 2;
  }
  if (cx < x2)
  {
    *((PWORD) addr) = (WORD)c;
  }
#endif /* _M_IX86 */
}


VOID
DIB_16BPP_VLine(SURFOBJ *SurfObj, LONG x, LONG y1, LONG y2, ULONG c)
{
#if defined(_M_IX86) && !defined(_MSC_VER)
  asm volatile(
    "   testl %2, %2"       "\n\t"
    "   jle   2f"           "\n\t"
    "   movl  %2, %%ecx"    "\n\t"
    "   shrl  $2, %2"       "\n\t"
    "   andl  $3, %%ecx"    "\n\t"
    "   jz    1f"           "\n\t"
    "0:"                    "\n\t"
    "   movw  %%ax, (%0)"   "\n\t"
    "   addl  %1, %0"       "\n\t"
    "   decl  %%ecx"        "\n\t"
    "   jnz   0b"           "\n\t"
    "   testl %2, %2"       "\n\t"
    "   jz    2f"           "\n\t"
    "1:"                    "\n\t"
    "   movw  %%ax, (%0)"   "\n\t"
    "   addl  %1, %0"       "\n\t"
    "   movw  %%ax, (%0)"   "\n\t"
    "   addl  %1, %0"       "\n\t"
    "   movw  %%ax, (%0)"   "\n\t"
    "   addl  %1, %0"       "\n\t"
    "   movw  %%ax, (%0)"   "\n\t"
    "   addl  %1, %0"       "\n\t"
    "   decl  %2"           "\n\t"
    "   jnz   1b"           "\n\t"
    "2:"                    "\n\t"
    : /* no output */
  : "r"((PBYTE)SurfObj->pvScan0 + (y1 * SurfObj->lDelta) + (x * sizeof (WORD))),
    "r"(SurfObj->lDelta), "r"(y2 - y1), "a"(c)
    : "cc", "memory", "%ecx");
#else
  PBYTE byteaddr = (PBYTE)(ULONG_PTR)SurfObj->pvScan0 + y1 * SurfObj->lDelta;
  PWORD addr = (PWORD)byteaddr + x;
  LONG lDelta = SurfObj->lDelta;

  byteaddr = (PBYTE)addr;
  while(y1++ < y2)
  {
    *addr = (WORD)c;

    byteaddr += lDelta;
    addr = (PWORD)byteaddr;
  }
#endif
}

BOOLEAN
DIB_16BPP_BitBltSrcCopy(PBLTINFO BltInfo)
{
  LONG     i, j, sx, sy, xColor, f1;
  PBYTE    SourceBits, DestBits, SourceLine, DestLine;
  PBYTE    SourceBits_4BPP, SourceLine_4BPP;
  DestBits = (PBYTE)BltInfo->DestSurface->pvScan0 + (BltInfo->DestRect.top * BltInfo->DestSurface->lDelta) + 2 * BltInfo->DestRect.left;

  switch(BltInfo->SourceSurface->iBitmapFormat)
  {
  case BMF_1BPP:
    sx = BltInfo->SourcePoint.x;
    sy = BltInfo->SourcePoint.y;
    for (j=BltInfo->DestRect.top; j<BltInfo->DestRect.bottom; j++)
    {
      sx = BltInfo->SourcePoint.x;
      for (i=BltInfo->DestRect.left; i<BltInfo->DestRect.right; i++)
      {
        if(DIB_1BPP_GetPixel(BltInfo->SourceSurface, sx, sy) == 0)
        {
          DIB_16BPP_PutPixel(BltInfo->DestSurface, i, j,
            XLATEOBJ_iXlate(BltInfo->XlateSourceToDest, 0));
        }
        else
        {
          DIB_16BPP_PutPixel(BltInfo->DestSurface, i, j,
            XLATEOBJ_iXlate(BltInfo->XlateSourceToDest, 1));
        }
        sx++;
      }
      sy++;
    }
    break;

  case BMF_4BPP:
    SourceBits_4BPP = (PBYTE)BltInfo->SourceSurface->pvScan0 +
      (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta) +
      (BltInfo->SourcePoint.x >> 1);

    for (j=BltInfo->DestRect.top; j<BltInfo->DestRect.bottom; j++)
    {
      SourceLine_4BPP = SourceBits_4BPP;
      sx = BltInfo->SourcePoint.x;
      f1 = sx & 1;

      for (i=BltInfo->DestRect.left; i<BltInfo->DestRect.right; i++)
      {
        xColor = XLATEOBJ_iXlate(BltInfo->XlateSourceToDest,
          (*SourceLine_4BPP & altnotmask[f1]) >> (4 * (1 - f1)));
        DIB_16BPP_PutPixel(BltInfo->DestSurface, i, j, xColor);
        if(f1 == 1)
        {
          SourceLine_4BPP++;
          f1 = 0;
        }
        else
        {
          f1 = 1;
        }
        sx++;
      }
      SourceBits_4BPP += BltInfo->SourceSurface->lDelta;
    }
    break;

  case BMF_8BPP:
    SourceLine = (PBYTE)BltInfo->SourceSurface->pvScan0 +
      (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta) +
      BltInfo->SourcePoint.x;
    DestLine = DestBits;

    for (j = BltInfo->DestRect.top; j < BltInfo->DestRect.bottom; j++)
    {
      SourceBits = SourceLine;
      DestBits = DestLine;

      for (i = BltInfo->DestRect.left; i < BltInfo->DestRect.right; i++)
      {
        *((WORD *)DestBits) = (WORD)XLATEOBJ_iXlate(
          BltInfo->XlateSourceToDest, *SourceBits);
        SourceBits += 1;
        DestBits += 2;
      }

      SourceLine += BltInfo->SourceSurface->lDelta;
      DestLine += BltInfo->DestSurface->lDelta;
    }
    break;

  case BMF_16BPP:
    if (NULL == BltInfo->XlateSourceToDest || 0 !=
      (BltInfo->XlateSourceToDest->flXlate & XO_TRIVIAL))
    {
      if (BltInfo->DestRect.top < BltInfo->SourcePoint.y)
      {
        SourceBits = (PBYTE)BltInfo->SourceSurface->pvScan0 +
          (BltInfo->SourcePoint.y *
          BltInfo->SourceSurface->lDelta) + 2 *
          BltInfo->SourcePoint.x;

        for (j = BltInfo->DestRect.top; j < BltInfo->DestRect.bottom; j++)
        {
          RtlMoveMemory(DestBits, SourceBits,
            2 * (BltInfo->DestRect.right -
            BltInfo->DestRect.left));

          SourceBits += BltInfo->SourceSurface->lDelta;
          DestBits += BltInfo->DestSurface->lDelta;
        }
      }
      else
      {
        SourceBits = (PBYTE)BltInfo->SourceSurface->pvScan0 +
          ((BltInfo->SourcePoint.y + BltInfo->DestRect.bottom -
          BltInfo->DestRect.top - 1) *
          BltInfo->SourceSurface->lDelta) + 2 *
          BltInfo->SourcePoint.x;

        DestBits = (PBYTE)BltInfo->DestSurface->pvScan0 +
          ((BltInfo->DestRect.bottom - 1) *
          BltInfo->DestSurface->lDelta) + 2 *
          BltInfo->DestRect.left;

        for (j = BltInfo->DestRect.bottom - 1;
          BltInfo->DestRect.top <= j; j--)
        {
          RtlMoveMemory(DestBits, SourceBits, 2 *
            (BltInfo->DestRect.right -
            BltInfo->DestRect.left));

          SourceBits -= BltInfo->SourceSurface->lDelta;
          DestBits -= BltInfo->DestSurface->lDelta;
        }
      }
    }
    else
    {
      if (BltInfo->DestRect.top < BltInfo->SourcePoint.y)
      {
        SourceLine = (PBYTE)BltInfo->SourceSurface->pvScan0 +
          (BltInfo->SourcePoint.y *
          BltInfo->SourceSurface->lDelta) + 2 *
          BltInfo->SourcePoint.x;

        DestLine = DestBits;
        for (j = BltInfo->DestRect.top; j < BltInfo->DestRect.bottom; j++)
        {
          SourceBits = SourceLine;
          DestBits = DestLine;
          for (i = BltInfo->DestRect.left; i <
            BltInfo->DestRect.right; i++)
          {
            *((WORD *)DestBits) = (WORD)XLATEOBJ_iXlate(
              BltInfo->XlateSourceToDest,
              *((WORD *)SourceBits));
            SourceBits += 2;
            DestBits += 2;
          }
          SourceLine += BltInfo->SourceSurface->lDelta;
          DestLine += BltInfo->DestSurface->lDelta;
        }
      }
      else
      {
        SourceLine = (PBYTE)BltInfo->SourceSurface->pvScan0 +
          ((BltInfo->SourcePoint.y +
          BltInfo->DestRect.bottom -
          BltInfo->DestRect.top - 1) *
          BltInfo->SourceSurface->lDelta) + 2 *
          BltInfo->SourcePoint.x;

        DestLine = (PBYTE)BltInfo->DestSurface->pvScan0 +
          ((BltInfo->DestRect.bottom - 1) *
          BltInfo->DestSurface->lDelta) + 2 *
          BltInfo->DestRect.left;

        for (j = BltInfo->DestRect.bottom - 1;
          BltInfo->DestRect.top <= j; j--)
        {
          SourceBits = SourceLine;
          DestBits = DestLine;
          for (i = BltInfo->DestRect.left; i <
            BltInfo->DestRect.right; i++)
          {
            *((WORD *)DestBits) = (WORD)XLATEOBJ_iXlate(
              BltInfo->XlateSourceToDest,
              *((WORD *)SourceBits));
            SourceBits += 2;
            DestBits += 2;
          }
          SourceLine -= BltInfo->SourceSurface->lDelta;
          DestLine -= BltInfo->DestSurface->lDelta;
        }
      }
    }
    break;

  case BMF_24BPP:
    SourceLine = (PBYTE)BltInfo->SourceSurface->pvScan0 +
      (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta) +
      3 * BltInfo->SourcePoint.x;

    DestLine = DestBits;

    for (j = BltInfo->DestRect.top; j < BltInfo->DestRect.bottom; j++)
    {
      SourceBits = SourceLine;
      DestBits = DestLine;

      for (i = BltInfo->DestRect.left; i < BltInfo->DestRect.right; i++)
      {
        xColor = (*(SourceBits + 2) << 0x10) +
          (*(SourceBits + 1) << 0x08) + (*(SourceBits));

        *((WORD *)DestBits) = (WORD)XLATEOBJ_iXlate(
          BltInfo->XlateSourceToDest, xColor);

        SourceBits += 3;
        DestBits += 2;
      }
      SourceLine += BltInfo->SourceSurface->lDelta;
      DestLine += BltInfo->DestSurface->lDelta;
    }
    break;

  case BMF_32BPP:
    SourceLine = (PBYTE)BltInfo->SourceSurface->pvScan0 +
      (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta) +
      4 * BltInfo->SourcePoint.x;

    DestLine = DestBits;

    for (j = BltInfo->DestRect.top; j < BltInfo->DestRect.bottom; j++)
    {
      SourceBits = SourceLine;
      DestBits = DestLine;

      for (i = BltInfo->DestRect.left; i < BltInfo->DestRect.right; i++)
      {
        *((WORD *)DestBits) = (WORD)XLATEOBJ_iXlate(
          BltInfo->XlateSourceToDest,
          *((PDWORD) SourceBits));
        SourceBits += 4;
        DestBits += 2;
      }

      SourceLine += BltInfo->SourceSurface->lDelta;
      DestLine += BltInfo->DestSurface->lDelta;
    }
    break;

  default:
    DPRINT1("DIB_16BPP_Bitblt: Unhandled Source BPP: %u\n",
      BitsPerFormat(BltInfo->SourceSurface->iBitmapFormat));
    return FALSE;
  }

  return TRUE;
}

/* Optimize for bitBlt */
BOOLEAN
DIB_16BPP_ColorFill(SURFOBJ* DestSurface, RECTL* DestRect, ULONG color)
{
  LONG DestY;

#if defined(_M_IX86) && !defined(_MSC_VER)
  /* This is about 10% faster than the generic C code below */
  ULONG delta = DestSurface->lDelta;
  ULONG width = (DestRect->right - DestRect->left) ;
  PULONG pos =  (PULONG) ((PBYTE)DestSurface->pvScan0 + DestRect->top * delta + (DestRect->left<<1));
  color = (color&0xffff);  /* If the color value is "abcd", put "abcdabcd" into color */
  color += (color<<16);

  for (DestY = DestRect->top; DestY< DestRect->bottom; DestY++)
  {
    __asm__ __volatile__ (
      "cld\n\t"
      "mov  %1,%%ebx\n\t"
      "mov  %2,%%edi\n\t"
      "test $0x03, %%edi\n\t"   /* Align to fullword boundary */
      "jz   1f\n\t"
      "stosw\n\t"
      "dec  %%ebx\n\t"
      "jz   2f\n"
      "1:\n\t"
      "mov  %%ebx,%%ecx\n\t"    /* Setup count of fullwords to fill */
      "shr  $1,%%ecx\n\t"
      "rep stosl\n\t"           /* The actual fill */
      "test $0x01, %%ebx\n\t"   /* One left to do at the right side? */
      "jz   2f\n\t"
      "stosw\n"
      "2:"
      :
      : "a" (color), "r" (width), "m" (pos)
      : "%ecx", "%ebx", "%edi");
    pos =(PULONG)((ULONG_PTR)pos + delta);
  }
#else /* _M_IX86 */

  for (DestY = DestRect->top; DestY< DestRect->bottom; DestY++)
  {
    DIB_16BPP_HLine (DestSurface, DestRect->left, DestRect->right, DestY, color);
  }
#endif
  return TRUE;
}

BOOLEAN
DIB_16BPP_TransparentBlt(SURFOBJ *DestSurf, SURFOBJ *SourceSurf,
                         RECTL*  DestRect,  RECTL *SourceRect,
                         XLATEOBJ *ColorTranslation, ULONG iTransColor)
{
  LONG RoundedRight, X, Y, SourceX = 0, SourceY = 0, wd;
  ULONG *DestBits, Source, Dest;

  LONG DstHeight;
  LONG DstWidth;
  LONG SrcHeight;
  LONG SrcWidth;

  DstHeight = DestRect->bottom - DestRect->top;
  DstWidth = DestRect->right - DestRect->left;
  SrcHeight = SourceRect->bottom - SourceRect->top;
  SrcWidth = SourceRect->right - SourceRect->left;

  RoundedRight = DestRect->right - ((DestRect->right - DestRect->left) & 0x1);
  DestBits = (ULONG*)((PBYTE)DestSurf->pvScan0 +
    (DestRect->left << 1) +
    DestRect->top * DestSurf->lDelta);
  wd = DestSurf->lDelta - ((DestRect->right - DestRect->left) << 1);

  for(Y = DestRect->top; Y < DestRect->bottom; Y++)
  {
    SourceY = SourceRect->top+(Y - DestRect->top) * SrcHeight / DstHeight;
    for(X = DestRect->left; X < RoundedRight; X += 2, DestBits++, SourceX += 2)
    {
      Dest = *DestBits;

      SourceX = SourceRect->left+(X - DestRect->left) * SrcWidth / DstWidth;
      if (SourceX >= 0 && SourceY >= 0 &&
        SourceSurf->sizlBitmap.cx > SourceX && SourceSurf->sizlBitmap.cy > SourceY)
      {
        Source = DIB_GetSourceIndex(SourceSurf, SourceX, SourceY);
        if(Source != iTransColor)
        {
          Dest &= 0xFFFF0000;
          Dest |= (XLATEOBJ_iXlate(ColorTranslation, Source) & 0xFFFF);
        }
      }

      SourceX = SourceRect->left+(X+1 - DestRect->left) * SrcWidth / DstWidth;
      if (SourceX >= 0 && SourceY >= 0 &&
        SourceSurf->sizlBitmap.cx > SourceX && SourceSurf->sizlBitmap.cy > SourceY)
      {
        Source = DIB_GetSourceIndex(SourceSurf, SourceX, SourceY);
        if(Source != iTransColor)
        {
          Dest &= 0xFFFF;
          Dest |= (XLATEOBJ_iXlate(ColorTranslation, Source) << 16);
        }
      }

      *DestBits = Dest;
    }

    if(X < DestRect->right)
    {
      SourceX = SourceRect->left+(X - DestRect->left) * SrcWidth / DstWidth;
      if (SourceX >= 0 && SourceY >= 0 &&
        SourceSurf->sizlBitmap.cx > SourceX && SourceSurf->sizlBitmap.cy > SourceY)
      {
        Source = DIB_GetSourceIndex(SourceSurf, SourceX, SourceY);
        if(Source != iTransColor)
        {
          *((USHORT*)DestBits) = (USHORT)XLATEOBJ_iXlate(ColorTranslation,
            Source);
        }
      }

      DestBits = (PULONG)((ULONG_PTR)DestBits + 2);
    }

    DestBits = (ULONG*)((ULONG_PTR)DestBits + wd);
  }

  return TRUE;
}

typedef union
{
  ULONG ul;
  struct
  {
    UCHAR red;
    UCHAR green;
    UCHAR blue;
    UCHAR alpha;
  } col;
} NICEPIXEL32;

typedef union
{
  USHORT us;
  struct
  {
    USHORT blue  :5;
    USHORT green :6;
    USHORT red   :5;
  } col;
} NICEPIXEL16_565;

typedef union
{
  USHORT us;
  struct
  {
    USHORT blue  :5;
    USHORT green :5;
    USHORT red   :5;
    USHORT xxxx  :1;
  } col;
} NICEPIXEL16_555;

static __inline UCHAR
Clamp6(ULONG val)
{
   return (val > 63) ? 63 : (UCHAR)val;
}

static __inline UCHAR
Clamp5(ULONG val)
{
   return (val > 31) ? 31 : (UCHAR)val;
}

BOOLEAN
DIB_16BPP_AlphaBlend(SURFOBJ* Dest, SURFOBJ* Source, RECTL* DestRect,
                     RECTL* SourceRect, CLIPOBJ* ClipRegion,
                     XLATEOBJ* ColorTranslation, BLENDOBJ* BlendObj)
{
  INT DstX, DstY, SrcX, SrcY;
  BLENDFUNCTION BlendFunc;
  NICEPIXEL32 SrcPixel32;
  UCHAR Alpha;
  EXLATEOBJ* pexlo;
  EXLATEOBJ exloSrcRGB;

  DPRINT("DIB_16BPP_AlphaBlend: srcRect: (%d,%d)-(%d,%d), dstRect: (%d,%d)-(%d,%d)\n",
    SourceRect->left, SourceRect->top, SourceRect->right, SourceRect->bottom,
    DestRect->left, DestRect->top, DestRect->right, DestRect->bottom);

  BlendFunc = BlendObj->BlendFunction;
  if (BlendFunc.BlendOp != AC_SRC_OVER)
  {
    DPRINT1("BlendOp != AC_SRC_OVER\n");
    return FALSE;
  }
  if (BlendFunc.BlendFlags != 0)
  {
    DPRINT1("BlendFlags != 0\n");
    return FALSE;
  }
  if ((BlendFunc.AlphaFormat & ~AC_SRC_ALPHA) != 0)
  {
    DPRINT1("Unsupported AlphaFormat (0x%x)\n", BlendFunc.AlphaFormat);
    return FALSE;
  }
  if ((BlendFunc.AlphaFormat & AC_SRC_ALPHA) != 0 &&
          (BitsPerFormat(Source->iBitmapFormat) != 32))
  {
    DPRINT1("Source bitmap must be 32bpp when AC_SRC_ALPHA is set\n");
    return FALSE;
  }

  if (!ColorTranslation)
  {
    DPRINT1("ColorTranslation must not be NULL!\n");
    return FALSE;
  }

  pexlo = CONTAINING_RECORD(ColorTranslation, EXLATEOBJ, xlo);
  EXLATEOBJ_vInitialize(&exloSrcRGB, pexlo->ppalSrc, &gpalRGB, 0, 0, 0);

  if (pexlo->ppalDst->flFlags & PAL_RGB16_555)
  {
      NICEPIXEL16_555 DstPixel16;

      SrcY = SourceRect->top;
      DstY = DestRect->top;
      while ( DstY < DestRect->bottom )
      {
        SrcX = SourceRect->left;
        DstX = DestRect->left;
        while(DstX < DestRect->right)
        {
          SrcPixel32.ul = DIB_GetSource(Source, SrcX, SrcY, &exloSrcRGB.xlo);
          SrcPixel32.col.red = (SrcPixel32.col.red * BlendFunc.SourceConstantAlpha) / 255;
          SrcPixel32.col.green = (SrcPixel32.col.green * BlendFunc.SourceConstantAlpha) / 255;
          SrcPixel32.col.blue = (SrcPixel32.col.blue * BlendFunc.SourceConstantAlpha) / 255;

          Alpha = ((BlendFunc.AlphaFormat & AC_SRC_ALPHA) != 0) ?
               (SrcPixel32.col.alpha * BlendFunc.SourceConstantAlpha) / 255 :
               BlendFunc.SourceConstantAlpha;

          Alpha >>= 3;

          DstPixel16.us = DIB_16BPP_GetPixel(Dest, DstX, DstY) & 0xFFFF;
          /* Perform bit loss */
          SrcPixel32.col.red >>= 3;
          SrcPixel32.col.green >>= 3;
          SrcPixel32.col.blue >>= 3;

          /* Do the blend in the right bit depth */
          DstPixel16.col.red = Clamp5((DstPixel16.col.red * (31 - Alpha)) / 31 + SrcPixel32.col.red);
          DstPixel16.col.green = Clamp5((DstPixel16.col.green * (31 - Alpha)) / 31 + SrcPixel32.col.green);
          DstPixel16.col.blue = Clamp5((DstPixel16.col.blue * (31 - Alpha)) / 31 + SrcPixel32.col.blue);

          DIB_16BPP_PutPixel(Dest, DstX, DstY, DstPixel16.us);

          DstX++;
          SrcX = SourceRect->left + ((DstX-DestRect->left)*(SourceRect->right - SourceRect->left))
                                                /(DestRect->right-DestRect->left);
        }
        DstY++;
        SrcY = SourceRect->top + ((DstY-DestRect->top)*(SourceRect->bottom - SourceRect->top))
                                                /(DestRect->bottom-DestRect->top);
      }
  }
  else
  {
      NICEPIXEL16_565 DstPixel16;
      UCHAR Alpha6, Alpha5;

      SrcY = SourceRect->top;
      DstY = DestRect->top;
      while ( DstY < DestRect->bottom )
      {
        SrcX = SourceRect->left;
        DstX = DestRect->left;
        while(DstX < DestRect->right)
        {
          SrcPixel32.ul = DIB_GetSource(Source, SrcX, SrcY, &exloSrcRGB.xlo);
          SrcPixel32.col.red = (SrcPixel32.col.red * BlendFunc.SourceConstantAlpha) / 255;
          SrcPixel32.col.green = (SrcPixel32.col.green * BlendFunc.SourceConstantAlpha) / 255;
          SrcPixel32.col.blue = (SrcPixel32.col.blue * BlendFunc.SourceConstantAlpha) / 255;

          Alpha = ((BlendFunc.AlphaFormat & AC_SRC_ALPHA) != 0) ?
               (SrcPixel32.col.alpha * BlendFunc.SourceConstantAlpha) / 255 :
               BlendFunc.SourceConstantAlpha;

          Alpha6 = Alpha >> 2;
          Alpha5 = Alpha >> 3;

          DstPixel16.us = DIB_16BPP_GetPixel(Dest, DstX, DstY) & 0xFFFF;
          /* Perform bit loss */
          SrcPixel32.col.red >>= 3;
          SrcPixel32.col.green >>= 2;
          SrcPixel32.col.blue >>= 3;

          /* Do the blend in the right bit depth */
          DstPixel16.col.red = Clamp5((DstPixel16.col.red * (31 - Alpha5)) / 31 + SrcPixel32.col.red);
          DstPixel16.col.green = Clamp6((DstPixel16.col.green * (63 - Alpha6)) / 63 + SrcPixel32.col.green);
          DstPixel16.col.blue = Clamp5((DstPixel16.col.blue * (31 - Alpha5)) / 31 + SrcPixel32.col.blue);

          DIB_16BPP_PutPixel(Dest, DstX, DstY, DstPixel16.us);

          DstX++;
          SrcX = SourceRect->left + ((DstX-DestRect->left)*(SourceRect->right - SourceRect->left))
                                                /(DestRect->right-DestRect->left);
        }
        DstY++;
        SrcY = SourceRect->top + ((DstY-DestRect->top)*(SourceRect->bottom - SourceRect->top))
                                                /(DestRect->bottom-DestRect->top);
      }
  }

  EXLATEOBJ_vCleanup(&exloSrcRGB);

  return TRUE;
}

/* EOF */