dib32bpp.c

Go to the documentation of this file.

/*
 * PROJECT:         Win32 subsystem
 * LICENSE:         See COPYING in the top level directory
 * FILE:            win32ss/gdi/dib/dib32bpp.c
 * PURPOSE:         Device Independant Bitmap functions, 32bpp
 * PROGRAMMERS:     Jason Filby
 *                  Thomas Bluemel
 *                  Gregor Anich
 *                  Doug Lyons
 */

#include <win32k.h>

#define NDEBUG
#include <debug.h>

#define DEC_OR_INC(var, decTrue, amount) \
    ((var) = (decTrue) ? ((var) - (amount)) : ((var) + (amount)))

VOID
DIB_32BPP_PutPixel(SURFOBJ *SurfObj, LONG x, LONG y, ULONG c)
{
  PBYTE byteaddr = (PBYTE)SurfObj->pvScan0 + y * SurfObj->lDelta;
  PDWORD addr = (PDWORD)byteaddr + x;

  *addr = c;
}

ULONG
DIB_32BPP_GetPixel(SURFOBJ *SurfObj, LONG x, LONG y)
{
  PBYTE byteaddr = (PBYTE)SurfObj->pvScan0 + y * SurfObj->lDelta;
  PDWORD addr = (PDWORD)byteaddr + x;

  return (ULONG)(*addr);
}

VOID
DIB_32BPP_VLine(SURFOBJ *SurfObj, LONG x, LONG y1, LONG y2, ULONG c)
{
  PBYTE byteaddr = (PBYTE)SurfObj->pvScan0 + y1 * SurfObj->lDelta;
  PDWORD addr = (PDWORD)byteaddr + x;
  LONG lDelta = SurfObj->lDelta >> 2; // >> 2 == / sizeof(DWORD)

  byteaddr = (PBYTE)addr;
  while (y1++ < y2)
  {
    *addr = (DWORD)c;
    addr += lDelta;
  }
}

BOOLEAN
DIB_32BPP_BitBltSrcCopy(PBLTINFO BltInfo)
{
  LONG     i, j, sx, sy, xColor, f1;
  PBYTE    SourceBits, DestBits, SourceLine, DestLine;
  PBYTE    SourceBitsT, SourceBitsB, DestBitsT, DestBitsB;
  PBYTE    SourceBits_4BPP, SourceLine_4BPP;
  PDWORD   Source32, Dest32;
  DWORD    Index, DestWidth, DestHeight;
  BOOLEAN  bTopToBottom, bLeftToRight;
  BOOLEAN  blDeltaSrcNeg, blDeltaDestNeg;
  BOOLEAN  blDeltaAdjustDone = FALSE;

  DPRINT("DIB_32BPP_BitBltSrcCopy: SourcePoint (%d, %d), SourceSurface cx/cy (%d/%d), "
         "DestSurface cx/cy (%d/%d) DestRect: (%d,%d)-(%d,%d)\n",
         BltInfo->SourcePoint.x, BltInfo->SourcePoint.y,
         BltInfo->SourceSurface->sizlBitmap.cx, BltInfo->SourceSurface->sizlBitmap.cy,
         BltInfo->DestSurface->sizlBitmap.cx, BltInfo->DestSurface->sizlBitmap.cy,
         BltInfo->DestRect.left, BltInfo->DestRect.top, BltInfo->DestRect.right, BltInfo->DestRect.bottom);

  DPRINT("BltInfo->DestSurface->lDelta is '%d' and BltInfo->SourceSurface->lDelta is '%d'.\n",
           BltInfo->DestSurface->lDelta,  BltInfo->SourceSurface->lDelta);

  DPRINT("iBitmapFormat is %d and width,height is (%d,%d).\n", BltInfo->SourceSurface->iBitmapFormat,
         BltInfo->DestRect.right - BltInfo->DestRect.left, BltInfo->DestRect.bottom - BltInfo->DestRect.top);

  DPRINT("BltInfo->SourcePoint.x is '%d' and BltInfo->SourcePoint.y is '%d'.\n",
         BltInfo->SourcePoint.x, BltInfo->SourcePoint.y);

  /* Do not deal with negative numbers for these values */
  if ((BltInfo->DestRect.left < 0) || (BltInfo->DestRect.top < 0) || 
      (BltInfo->DestRect.right < 0) || (BltInfo->DestRect.bottom < 0))
    return FALSE;

  /* Detect negative lDelta's meaning Bottom-Up bitmaps */
  blDeltaSrcNeg = BltInfo->SourceSurface->lDelta < 0;
  blDeltaDestNeg = BltInfo->DestSurface->lDelta < 0;

  /* Get back left to right flip here */
  bLeftToRight = BltInfo->DestRect.left > BltInfo->DestRect.right;

  /* Check for top to bottom flip needed. */
  bTopToBottom = BltInfo->DestRect.top > BltInfo->DestRect.bottom;

  DPRINT("bTopToBottom is '%d' and DestSurface->lDelta < 0 is '%d' and SourceSurface->lDelta < 0 is '%d'.\n",
           bTopToBottom, BltInfo->DestSurface->lDelta < 0 ? 1 : 0,  BltInfo->SourceSurface->lDelta < 0 ? 1 : 0);

  /* Make WellOrdered with top < bottom and left < right */
  RECTL_vMakeWellOrdered(&BltInfo->DestRect);

  DestWidth = BltInfo->DestRect.right - BltInfo->DestRect.left;
  DestHeight = BltInfo->DestRect.bottom - BltInfo->DestRect.top;

  DestBits = (PBYTE)BltInfo->DestSurface->pvScan0
    + (BltInfo->DestRect.top * BltInfo->DestSurface->lDelta)
    + 4 * BltInfo->DestRect.left;

  DPRINT("iBitmapFormat is %d and width,height is (%d,%d).\n", BltInfo->SourceSurface->iBitmapFormat,
         DestWidth, DestHeight);

  switch (BltInfo->SourceSurface->iBitmapFormat)
  {
  case BMF_1BPP:
    DPRINT("1BPP Case Selected with DestRect Width of '%d'.\n",
           DestWidth);

    if (bLeftToRight || bTopToBottom)
    DPRINT("bLeftToRight is '%d' and bTopToBottom is '%d'.\n", bLeftToRight, bTopToBottom);

    sx = BltInfo->SourcePoint.x;

    /* This sets sy to the top line */
    sy = BltInfo->SourcePoint.y;

    if (bTopToBottom)
    {
      /* This sets sy to the bottom line */
      sy += BltInfo->SourceSurface->lDelta * (DestHeight - 1);
    }

    for (j=BltInfo->DestRect.top; j<BltInfo->DestRect.bottom; j++)
    {
      sx = BltInfo->SourcePoint.x;

      if (bLeftToRight)
      {
        /* This sets the sx to the rightmost pixel */
        sx += (DestWidth - 1);
      }

      for (i = BltInfo->DestRect.left; i < BltInfo->DestRect.right; i++)
      {
        if (DIB_1BPP_GetPixel(BltInfo->SourceSurface, sx, sy) == 0)
        {
          DIB_32BPP_PutPixel(BltInfo->DestSurface, i, j, XLATEOBJ_iXlate(BltInfo->XlateSourceToDest, 0));
        }
        else
        {
          DIB_32BPP_PutPixel(BltInfo->DestSurface, i, j, XLATEOBJ_iXlate(BltInfo->XlateSourceToDest, 1));
        }

        DEC_OR_INC(sx, bLeftToRight, 1);
      }
      DEC_OR_INC(sy, bTopToBottom, 1);
    }
    break;

  case BMF_4BPP:
    DPRINT("4BPP Case Selected with DestRect Width of '%d'.\n",
           DestWidth);

    if (bLeftToRight || bTopToBottom)
    DPRINT("bLeftToRight is '%d' and bTopToBottom is '%d'.\n", bLeftToRight, bTopToBottom);

    /* This sets SourceBits_4BPP to the top line */
    SourceBits_4BPP = (PBYTE)BltInfo->SourceSurface->pvScan0
      + (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta)
      + (BltInfo->SourcePoint.x >> 1);

    if (bTopToBottom)
    {
      /* This sets SourceBits_4BPP to the bottom line */
      SourceBits_4BPP += BltInfo->SourceSurface->lDelta * (DestHeight - 1);
    }

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

      if (bLeftToRight)
      {
        /* This sets sx to the rightmost pixel */
        sx += (DestWidth - 1);
      }

      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_32BPP_PutPixel(BltInfo->DestSurface, i, j, xColor);
        if (f1 == 1) {
          DEC_OR_INC(SourceLine_4BPP, bLeftToRight, 1);
          f1 = 0;
        } else {
          f1 = 1;
        }
        DEC_OR_INC(sx, bLeftToRight, 1);
      }
      DEC_OR_INC(SourceBits_4BPP, bTopToBottom, BltInfo->SourceSurface->lDelta);
    }
    break;

  case BMF_8BPP:
    DPRINT("8BPP Case Selected with DestRect Width of '%d'.\n",
           DestWidth);

    if (bLeftToRight || bTopToBottom)
    DPRINT("bLeftToRight is '%d' and bTopToBottom is '%d'.\n", bLeftToRight, bTopToBottom);

    /* This sets SourceLine to the top line */
    SourceLine = (PBYTE)BltInfo->SourceSurface->pvScan0
      + (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta)
      + BltInfo->SourcePoint.x;
    DestLine = DestBits;

    if (bTopToBottom)
    {
      /* This sets SourceLine to the bottom line */
      SourceLine += BltInfo->SourceSurface->lDelta * (DestHeight - 1);
    }

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

      if (bLeftToRight)
      {
        /* This sets the SourceBits to the rightmost pixel */
        SourceBits += (DestWidth - 1);
      }

      for (i = BltInfo->DestRect.left; i < BltInfo->DestRect.right; i++)
      {
        xColor = *SourceBits;
        *((PDWORD) DestBits) = (DWORD)XLATEOBJ_iXlate(BltInfo->XlateSourceToDest, xColor);
        DEC_OR_INC(SourceBits, bLeftToRight, 1);
        DestBits += 4;
      }
      DEC_OR_INC(SourceLine, bTopToBottom, BltInfo->SourceSurface->lDelta);
      DestLine += BltInfo->DestSurface->lDelta;
    }
    break;

  case BMF_16BPP:
    DPRINT("16BPP Case Selected with DestRect Width of '%d'.\n",
            DestWidth);

    if (bLeftToRight || bTopToBottom)
    DPRINT("bLeftToRight is '%d' and bTopToBottom is '%d'.\n", bLeftToRight, bTopToBottom);

    /* This sets SourceLine to the top line */
    SourceLine = (PBYTE)BltInfo->SourceSurface->pvScan0
      + (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta)
      + 2 * BltInfo->SourcePoint.x;
    DestLine = DestBits;

    if (bTopToBottom)
    {
      /* This sets SourceLine to the bottom line */
      SourceLine += BltInfo->SourceSurface->lDelta * (DestHeight - 1);
    }

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

      if (bLeftToRight)
      {
        /* This sets the SourceBits to the rightmost pixel */
        SourceBits += (DestWidth - 1) * 2;
      }

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

      DEC_OR_INC(SourceLine, bTopToBottom, BltInfo->SourceSurface->lDelta);
      DestLine += BltInfo->DestSurface->lDelta;
    }
    break;

  case BMF_24BPP:
    DPRINT("24BPP Case Selected with DestRect Width of '%d'.\n",
      DestWidth);

    if (bLeftToRight || bTopToBottom)
    DPRINT("bLeftToRight is '%d' and bTopToBottom is '%d'.\n", bLeftToRight, bTopToBottom);

    /* This sets SourceLine to the top line */
    SourceLine = (PBYTE)BltInfo->SourceSurface->pvScan0
      + (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta)
      + 3 * BltInfo->SourcePoint.x;

    if (bTopToBottom)
    {
      /* This sets SourceLine to the bottom line */
      SourceLine += BltInfo->SourceSurface->lDelta * (DestHeight - 1);
    }

    DestLine = DestBits;

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

      if (bLeftToRight)
      {
        /* This sets the SourceBits to the rightmost pixel */
        SourceBits += (DestWidth - 1) * 3;
      }

      for (i = BltInfo->DestRect.left; i < BltInfo->DestRect.right; i++)
      {
        xColor = (*(SourceBits + 2) << 0x10) +
          (*(SourceBits + 1) << 0x08) +
          (*(SourceBits));
        *((PDWORD)DestBits) = (DWORD)XLATEOBJ_iXlate(BltInfo->XlateSourceToDest, xColor);
        DEC_OR_INC(SourceBits, bLeftToRight, 3);
        DestBits += 4;
      }

      DEC_OR_INC(SourceLine, bTopToBottom, BltInfo->SourceSurface->lDelta);
      DestLine += BltInfo->DestSurface->lDelta;
    }
    break;

  case BMF_32BPP:
    DPRINT("32BPP Case Selected with SourcePoint (%d,%d) and DestRect Width/height of '%d/%d' DestRect: (%d,%d)-(%d,%d).\n",
           BltInfo->SourcePoint.x, BltInfo->SourcePoint.y, DestWidth, DestHeight,
           BltInfo->DestRect.left, BltInfo->DestRect.top, BltInfo->DestRect.right, BltInfo->DestRect.bottom);

    if (bLeftToRight || bTopToBottom)
    DPRINT("bLeftToRight is '%d' and bTopToBottom is '%d'.\n", bLeftToRight, bTopToBottom);

    /* This handles the negative lDelta's which represent Top-to-Bottom bitmaps */
    if (((blDeltaSrcNeg || blDeltaDestNeg) && !(blDeltaSrcNeg && blDeltaDestNeg)) && bTopToBottom)
    {
      DPRINT("Adjusting for lDelta's here.\n");
      if (BltInfo->DestRect.top < BltInfo->SourcePoint.y)
      {
        /* SourceBits points to top-left pixel for lDelta < 0 and bottom-left for lDelta > 0 */
        SourceBits = (PBYTE)BltInfo->SourceSurface->pvScan0
          + (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta)
          + 4 * BltInfo->SourcePoint.x;
        for (j = BltInfo->DestRect.top; j < BltInfo->DestRect.bottom; j++)
        {
          RtlMoveMemory(DestBits, SourceBits, 4 * DestWidth);
          SourceBits += BltInfo->SourceSurface->lDelta;
          DestBits += BltInfo->DestSurface->lDelta;
        }
      }
      else
      {
        /* SourceBits points to bottom-left pixel for lDelta < 0 and top-left for lDelta > 0 */
        SourceBits = (PBYTE)BltInfo->SourceSurface->pvScan0
          + ((BltInfo->SourcePoint.y
          + DestHeight - 1) * BltInfo->SourceSurface->lDelta)
          + 4 * BltInfo->SourcePoint.x;
        /* SourceBits points to bottom-left pixel for lDelta < 0 and top-left for lDelta > 0 */
        DestBits = (PBYTE)BltInfo->DestSurface->pvScan0
          + ((BltInfo->DestRect.bottom - 1) * BltInfo->DestSurface->lDelta)
          + 4 * BltInfo->DestRect.left;
        for (j = BltInfo->DestRect.bottom - 1; BltInfo->DestRect.top <= j; j--)
        {
          RtlMoveMemory(DestBits, SourceBits, 4 * DestWidth);
          SourceBits -= BltInfo->SourceSurface->lDelta;
          DestBits -= BltInfo->DestSurface->lDelta;
        }
      }
      blDeltaAdjustDone = TRUE;
    }

    /* This tests for whether we can use simplified/quicker code below.
     * It works for increasing source and destination areas only and there is no overlap and no flip.
     */
    if ((BltInfo->XlateSourceToDest == NULL ||
      (BltInfo->XlateSourceToDest->flXlate & XO_TRIVIAL) != 0) &&
      (!bTopToBottom && !bLeftToRight))
    {
      DPRINT("XO_TRIVIAL is TRUE.\n");

      if (BltInfo->DestRect.top < BltInfo->SourcePoint.y)
      {
        /* SourceBits points to top-left pixel for lDelta < 0 and bottom-left for lDelta > 0 */
        SourceBits = (PBYTE)BltInfo->SourceSurface->pvScan0
          + (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta)
          + 4 * BltInfo->SourcePoint.x;
        for (j = BltInfo->DestRect.top; j < BltInfo->DestRect.bottom; j++)
        {
          RtlMoveMemory(DestBits, SourceBits, 4 * DestWidth);
          SourceBits += BltInfo->SourceSurface->lDelta;
          DestBits += BltInfo->DestSurface->lDelta;
        }
      }
      else
      {
        /* SourceBits points to bottom-left pixel for lDelta < 0 and top-left for lDelta > 0 */
        SourceBits = (PBYTE)BltInfo->SourceSurface->pvScan0
          + ((BltInfo->SourcePoint.y
          + DestHeight - 1) * BltInfo->SourceSurface->lDelta)
          + 4 * BltInfo->SourcePoint.x;
        /* SourceBits points to bottom-left pixel for lDelta < 0 and top-left for lDelta > 0 */
        DestBits = (PBYTE)BltInfo->DestSurface->pvScan0
          + ((BltInfo->DestRect.bottom - 1) * BltInfo->DestSurface->lDelta)
          + 4 * BltInfo->DestRect.left;
        for (j = BltInfo->DestRect.bottom - 1; BltInfo->DestRect.top <= j; j--)
        {
          RtlMoveMemory(DestBits, SourceBits, 4 * DestWidth);
          SourceBits -= BltInfo->SourceSurface->lDelta;
          DestBits -= BltInfo->DestSurface->lDelta;
        }
      }
    }
    else
    {
      DPRINT("XO_TRIVIAL is NOT TRUE.\n");

      if (!bTopToBottom && !bLeftToRight)
      {
        if (BltInfo->DestRect.top < BltInfo->SourcePoint.y)
        {
          SourceBits = ((PBYTE)BltInfo->SourceSurface->pvScan0
            + (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta)
            + 4 * BltInfo->SourcePoint.x);
          for (j = BltInfo->DestRect.top; j < BltInfo->DestRect.bottom; j++)
          {
            if (BltInfo->DestRect.left < BltInfo->SourcePoint.x)
            {
              Dest32 = (DWORD *) DestBits;
              Source32 = (DWORD *) SourceBits;
              for (i = BltInfo->DestRect.left; i < BltInfo->DestRect.right; i++)
              {
                *Dest32++ = XLATEOBJ_iXlate(BltInfo->XlateSourceToDest, *Source32++);
              }
            }
            else
            {
              Dest32 = (DWORD *) DestBits + (DestWidth - 1);
              Source32 = (DWORD *) SourceBits + (DestWidth - 1);
              for (i = BltInfo->DestRect.right - 1; BltInfo->DestRect.left <= i; i--)
              {
                *Dest32-- = XLATEOBJ_iXlate(BltInfo->XlateSourceToDest, *Source32--);
              }
            }
            SourceBits += BltInfo->SourceSurface->lDelta;
            DestBits += BltInfo->DestSurface->lDelta;
          }
        }
        else
        {
          SourceBits = (PBYTE)BltInfo->SourceSurface->pvScan0
            + ((BltInfo->SourcePoint.y
            + DestHeight - 1) * BltInfo->SourceSurface->lDelta)
            + 4 * BltInfo->SourcePoint.x;
          DestBits = (PBYTE)BltInfo->DestSurface->pvScan0
            + ((BltInfo->DestRect.bottom - 1) * BltInfo->DestSurface->lDelta)
            + 4 * BltInfo->DestRect.left;
          for (j = BltInfo->DestRect.bottom - 1; BltInfo->DestRect.top <= j; j--)
          {
            if (BltInfo->DestRect.left < BltInfo->SourcePoint.x)
            {
              Dest32 = (DWORD *) DestBits;
              Source32 = (DWORD *) SourceBits;
              for (i = BltInfo->DestRect.left; i < BltInfo->DestRect.right; i++)
              {
                *Dest32++ = XLATEOBJ_iXlate(BltInfo->XlateSourceToDest, *Source32++);
              }
            }
            else
            {
              Dest32 = (DWORD *) DestBits + (DestWidth - 1);
              Source32 = (DWORD *) SourceBits + (DestWidth - 1);
              for (i = BltInfo->DestRect.right - 1; BltInfo->DestRect.left <= i; i--)
              {
                *Dest32-- = XLATEOBJ_iXlate(BltInfo->XlateSourceToDest, *Source32--);
              }
            }
            SourceBits -= BltInfo->SourceSurface->lDelta;
            DestBits -= BltInfo->DestSurface->lDelta;
          }
        }
      }
      else
      {
        /* Buffering for source and destination flip overlaps. Fixes KHMZ MirrorTest CORE-16642 */
        BOOL TopToBottomDone = FALSE;

        /* No need to flip a LeftToRight bitmap only one pixel wide */
        if ((bLeftToRight) && (DestWidth > 1))
        {
          DPRINT("Flip is bLeftToRight.\n");

          /* Allocate enough pixels for a row in DWORD's */
          DWORD *store = ExAllocatePoolWithTag(NonPagedPool,
            (DestWidth + 1) * 4, TAG_DIB);
          if (store == NULL)
          {
            DPRINT1("Storage Allocation Failed.\n");
            return FALSE;
          }

          /* This sets SourceBits to the bottom line */
          SourceBits = (PBYTE)BltInfo->SourceSurface->pvScan0
            + ((BltInfo->SourcePoint.y + DestHeight - 1)
            * BltInfo->SourceSurface->lDelta) + 4 * BltInfo->SourcePoint.x;

          /* This sets DestBits to the bottom line */
          DestBits = (PBYTE)BltInfo->DestSurface->pvScan0
           + (BltInfo->DestRect.bottom - 1) * BltInfo->DestSurface->lDelta
           + 4 * BltInfo->DestRect.left;

          for (j = BltInfo->DestRect.bottom - 1; BltInfo->DestRect.top <= j; j--)
          {

              /* Set Dest32 to right pixel */
              Dest32 = (DWORD *) DestBits + (DestWidth - 1);
              Source32 = (DWORD *) SourceBits;

              Index = 0;

              /* Store pixels from left to right */
              for (i = BltInfo->DestRect.right - 1; BltInfo->DestRect.left <= i; i--)
              {
                store[Index] = *Source32++;
                Index++;
              }

              Index = 0;

              /* Copy stored dat to pixels from right to left */
              for (i = BltInfo->DestRect.right - 1; BltInfo->DestRect.left <= i; i--)
              {
                *Dest32-- = store[Index];
                Index++;
              }
            SourceBits -= BltInfo->SourceSurface->lDelta;
            DestBits -= BltInfo->DestSurface->lDelta;
          }
          ExFreePoolWithTag(store, TAG_DIB);
          TopToBottomDone = TRUE;
        }

        /* Top to Botoom Handling if bitmap more than one pixel high */
        if ((bTopToBottom) && (DestHeight > 1))
         {
          /* Note: It is very important that this code remain optimized for time used.
           *   Otherwise you will have random crashes in ReactOS that are undesirable.
           *   For an example of this just try executing the code here two times.
           */

          DPRINT("Flip is bTopToBottom.\n");

          /* Allocate enough pixels for a row in DWORD's */
          DWORD *store = ExAllocatePoolWithTag(NonPagedPool,
            (DestWidth + 1) * 4, TAG_DIB);
          if (store == NULL)
          {
            DPRINT1("Storage Allocation Failed.\n");
            return FALSE;
          }

          /* This set DestBitsT to the top line */
          DestBitsT = (PBYTE)BltInfo->DestSurface->pvScan0
            + ((BltInfo->DestRect.top) * BltInfo->DestSurface->lDelta)
            + 4 * BltInfo->DestRect.left;

          /* This sets DestBitsB to the bottom line */
          DestBitsB = (PBYTE)BltInfo->DestSurface->pvScan0
           + (BltInfo->DestRect.bottom - 1) * BltInfo->DestSurface->lDelta
           + 4 * BltInfo->DestRect.left;

          /* The TopToBottomDone flag indicates that we are flipping for bTopToBottom and bLeftToRight
           * and have already completed the bLeftToRight. So we will lose our first flip output
           * unless we work with its output which is at the destination site. So in this case
           * our new Source becomes the previous outputs Destination.
           * Also in we use the same logic when we have corrected for negative lDelta's above
           * and already completed a flip from Source to Destination for the first step 
           */

          if (TopToBottomDone || blDeltaAdjustDone)
          {
            /* This sets SourceBitsB to the bottom line */
            SourceBitsB = DestBitsB;

            /* This sets SourceBitsT to the top line */
            SourceBitsT = DestBitsT;
          }
          else
          {
            /* This sets SourceBitsB to the bottom line */
            SourceBitsB = (PBYTE)BltInfo->SourceSurface->pvScan0
              + ((BltInfo->SourcePoint.y + DestHeight - 1)
              * BltInfo->SourceSurface->lDelta) + 4 * BltInfo->SourcePoint.x;

            /* This sets SourceBitsT to the top line */
            SourceBitsT = (PBYTE)BltInfo->SourceSurface->pvScan0
              + (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta) + 4 * BltInfo->SourcePoint.x;
          }

          /* Overlaps and Vertical flips do not mix well. So we test for this and handle it
           * by using two operations. First we just do a copy of the source to the destination.
           * Then we do a flip in place at the destination location and we are done.
           */
          if ((BltInfo->SourcePoint.y != BltInfo->DestRect.top) &&                        // The values are not equal and
             (abs(BltInfo->SourcePoint.y - BltInfo->DestRect.top) < (DestHeight + 2)) &&  // they are NOT seperated by > DestHeight 
             (BltInfo->SourceSurface->pvScan0 == BltInfo->DestSurface->pvScan0))          // and same surface (probably screen)
          {
            DPRINT("Flips Need Adjustments, so do move here.\n");

            if (BltInfo->DestRect.top < BltInfo->SourcePoint.y)
            {
              /* SourceBits points to top-left pixel for lDelta < 0 and bottom-left for lDelta > 0 */
              SourceBits = (PBYTE)BltInfo->SourceSurface->pvScan0
                + (BltInfo->SourcePoint.y * BltInfo->SourceSurface->lDelta)
                + 4 * BltInfo->SourcePoint.x;
              for (j = BltInfo->DestRect.top; j < BltInfo->DestRect.bottom; j++)
              {
                RtlMoveMemory(DestBits, SourceBits, 4 * DestWidth);
                SourceBits += BltInfo->SourceSurface->lDelta;
                DestBits += BltInfo->DestSurface->lDelta;
              }
            }
            else
            {
              /* SourceBits points to bottom-left pixel for lDelta < 0 and top-left for lDelta > 0 */
              SourceBits = (PBYTE)BltInfo->SourceSurface->pvScan0
                + ((BltInfo->SourcePoint.y
                + DestHeight - 1) * BltInfo->SourceSurface->lDelta)
                + 4 * BltInfo->SourcePoint.x;
              /* SourceBits points to bottom-left pixel for lDelta < 0 and top-left for lDelta > 0 */
              DestBits = (PBYTE)BltInfo->DestSurface->pvScan0
                + ((BltInfo->DestRect.bottom - 1) * BltInfo->DestSurface->lDelta)
                + 4 * BltInfo->DestRect.left;
              for (j = BltInfo->DestRect.bottom - 1; BltInfo->DestRect.top <= j; j--)
              {
                RtlMoveMemory(DestBits, SourceBits, 4 * DestWidth);
                SourceBits -= BltInfo->SourceSurface->lDelta;
                DestBits -= BltInfo->DestSurface->lDelta;
              }
            }

            /* This sets SourceBitsB to the bottom line */
            SourceBitsB = DestBitsB;

            /* This sets SourceBitsT to the top line */
            SourceBitsT = DestBitsT;
          }

          /* Vertical Flip code starts here */
          for (j = 0; j < DestHeight / 2 ; j++)
          {
            /* Store bottom row of Source pixels */
            RtlMoveMemory(store, SourceBitsB, 4 * DestWidth);

            /* Copy top Source row to bottom Destination row overwriting it */
            RtlMoveMemory(DestBitsB, SourceBitsT, 4 * DestWidth);

            /* Copy stored bottom row of Source pixels to Destination top row of pixels */
            RtlMoveMemory(DestBitsT, store, 4 * DestWidth);

            /* Index top rows down and bottom rows up */
            SourceBitsT += BltInfo->SourceSurface->lDelta;
            SourceBitsB -= BltInfo->SourceSurface->lDelta;

            DestBitsT += BltInfo->DestSurface->lDelta;
            DestBitsB -= BltInfo->DestSurface->lDelta;
          }
          if (DestHeight % 2)
          {
            /* If we had an odd number of lines we handle the center one here */
            DPRINT("Handling Top To Bottom with Odd Number of lines.\n");
            RtlMoveMemory(DestBitsB, SourceBitsT, 4 * DestWidth);
          }
          ExFreePoolWithTag(store, TAG_DIB);
        }
      }
    }
    break;

  default:
    DPRINT1("DIB_32BPP_BitBltSrcCopy: Unhandled Source BPP: %u\n", BitsPerFormat(BltInfo->SourceSurface->iBitmapFormat));
    return FALSE;
  }

  return TRUE;
}

BOOLEAN
DIB_32BPP_TransparentBlt(SURFOBJ *DestSurf, SURFOBJ *SourceSurf,
                         RECTL*  DestRect,  RECTL *SourceRect,
                         XLATEOBJ *ColorTranslation, ULONG iTransColor)
{
  LONG X, Y, SourceX, SourceY = 0, wd;
  ULONG *DestBits, Source = 0;

  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;

  DestBits = (ULONG*)((PBYTE)DestSurf->pvScan0 +
    (DestRect->left << 2) +
    DestRect->top * DestSurf->lDelta);
  wd = DestSurf->lDelta - ((DestRect->right - DestRect->left) << 2);

  for (Y = DestRect->top; Y < DestRect->bottom; Y++)
  {
    SourceY = SourceRect->top+(Y - DestRect->top) * SrcHeight / DstHeight;
    for (X = DestRect->left; X < DestRect->right; X++, 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 ((0x00FFFFFF & Source) != (0x00FFFFFF & iTransColor))
        {
          *DestBits = XLATEOBJ_iXlate(ColorTranslation, Source);
        }
      }
    }

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

  return TRUE;
}

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

static __inline UCHAR
Clamp8(ULONG val)
{
  return (val > 255) ? 255 : (UCHAR)val;
}

BOOLEAN
DIB_32BPP_AlphaBlend(SURFOBJ* Dest, SURFOBJ* Source, RECTL* DestRect,
                     RECTL* SourceRect, CLIPOBJ* ClipRegion,
                     XLATEOBJ* ColorTranslation, BLENDOBJ* BlendObj)
{
  INT Rows, Cols, SrcX, SrcY;
  register PULONG Dst;
  BLENDFUNCTION BlendFunc;
  register NICEPIXEL32 DstPixel, SrcPixel;
  UCHAR Alpha, SrcBpp;

  DPRINT("DIB_32BPP_AlphaBlend: SourceRect: (%d,%d)-(%d,%d), DestRect: (%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;
  }

  Dst = (PULONG)((ULONG_PTR)Dest->pvScan0 + (DestRect->top * Dest->lDelta) +
    (DestRect->left << 2));
  SrcBpp = BitsPerFormat(Source->iBitmapFormat);

  Rows = 0;
   SrcY = SourceRect->top;
   while (++Rows <= DestRect->bottom - DestRect->top)
  {
    Cols = 0;
    SrcX = SourceRect->left;
    while (++Cols <= DestRect->right - DestRect->left)
    {
      SrcPixel.ul = DIB_GetSource(Source, SrcX, SrcY, ColorTranslation);
      SrcPixel.col.red = (SrcPixel.col.red * BlendFunc.SourceConstantAlpha) / 255;
      SrcPixel.col.green = (SrcPixel.col.green * BlendFunc.SourceConstantAlpha)  / 255;
      SrcPixel.col.blue = (SrcPixel.col.blue * BlendFunc.SourceConstantAlpha) / 255;
      SrcPixel.col.alpha = (32 == SrcBpp) ?
                        (SrcPixel.col.alpha * BlendFunc.SourceConstantAlpha) / 255 :
                        BlendFunc.SourceConstantAlpha ;

      Alpha = ((BlendFunc.AlphaFormat & AC_SRC_ALPHA) != 0) ?
           SrcPixel.col.alpha : BlendFunc.SourceConstantAlpha ;

      DstPixel.ul = *Dst;
      DstPixel.col.red = Clamp8((DstPixel.col.red * (255 - Alpha)) / 255 + SrcPixel.col.red) ;
      DstPixel.col.green = Clamp8((DstPixel.col.green * (255 - Alpha)) / 255 + SrcPixel.col.green) ;
      DstPixel.col.blue = Clamp8((DstPixel.col.blue * (255 - Alpha)) / 255 + SrcPixel.col.blue) ;
      DstPixel.col.alpha = Clamp8((DstPixel.col.alpha * (255 - Alpha)) / 255 + SrcPixel.col.alpha) ;
      *Dst++ = DstPixel.ul;
      SrcX = SourceRect->left + (Cols*(SourceRect->right - SourceRect->left))/(DestRect->right - DestRect->left);
    }
    Dst = (PULONG)((ULONG_PTR)Dest->pvScan0 + ((DestRect->top + Rows) * Dest->lDelta) +
                (DestRect->left << 2));
    SrcY = SourceRect->top + (Rows*(SourceRect->bottom - SourceRect->top))/(DestRect->bottom - DestRect->top);
  }

  return TRUE;
}

/* EOF */