libmng_pixels.c

这个是Linux的qt源代码

/* ************************************************************************** */

mng_retcode display_rgb8 (mng_datap pData)
{
  mng_uint8p pScanline;
  mng_uint8p pDataline;
  mng_int32  iX;
  mng_uint16 iA16;
  mng_uint16 iFGr16, iFGg16, iFGb16;
  mng_uint16 iBGr16, iBGg16, iBGb16;
  mng_uint8  iA8;

#ifdef MNG_SUPPORT_TRACE
  MNG_TRACE (pData, MNG_FN_DISPLAY_RGB8, MNG_LC_START)
#endif
                                       /* viewable row ? */
  if ((pData->iRow >= pData->iSourcet) && (pData->iRow < pData->iSourceb))
  {                                    /* address destination row */
    pScanline = (mng_uint8p)pData->fGetcanvasline (((mng_handle)pData),
                                                   pData->iRow + pData->iDestt -
                                                   pData->iSourcet);
                                       /* adjust destination row starting-point */
    pScanline = pScanline + (pData->iCol * 3) + (pData->iDestl * 3);
    pDataline = pData->pRGBArow;       /* address source row */

    if (pData->bIsRGBA16)              /* adjust source row starting-point */
      pDataline = pDataline + ((pData->iSourcel / pData->iColinc) << 3);
    else
      pDataline = pDataline + ((pData->iSourcel / pData->iColinc) << 2);

    if (pData->bIsOpaque)              /* forget about transparency ? */
    {
      if (pData->bIsRGBA16)            /* 16-bit input row ? */
      {
        for (iX = pData->iSourcel + pData->iCol; iX < pData->iSourcer; iX += pData->iColinc)
        {                              /* scale down by dropping the LSB */
          *pScanline     = *pDataline;
          *(pScanline+1) = *(pDataline+2);
          *(pScanline+2) = *(pDataline+4);

          pScanline += (pData->iColinc * 3);
          pDataline += 8;
        }
      }
      else
      {
        for (iX = pData->iSourcel + pData->iCol; iX < pData->iSourcer; iX += pData->iColinc)
        {                              /* copy the values */
          *pScanline     = *pDataline;
          *(pScanline+1) = *(pDataline+1);
          *(pScanline+2) = *(pDataline+2);

          pScanline += (pData->iColinc * 3);
          pDataline += 4;
        }
      }
    }
    else
    {
      if (pData->bIsRGBA16)            /* 16-bit input row ? */
      {
        for (iX = pData->iSourcel + pData->iCol; iX < pData->iSourcer; iX += pData->iColinc)
        {
          iA16 = mng_get_uint16 (pDataline+6);

          if (iA16)                    /* any opacity at all ? */
          {
            if (iA16 == 0xFFFF)        /* fully opaque ? */
            {                          /* scale down by dropping the LSB */
              *pScanline     = *pDataline;
              *(pScanline+1) = *(pDataline+2);
              *(pScanline+2) = *(pDataline+4);
            }
            else
            {                          /* get the proper values */
              iFGr16 = mng_get_uint16 (pDataline  );
              iFGg16 = mng_get_uint16 (pDataline+2);
              iFGb16 = mng_get_uint16 (pDataline+4);
                                       /* scale background up */
              iBGr16 = (mng_uint16)(*pScanline    );
              iBGg16 = (mng_uint16)(*(pScanline+1));
              iBGb16 = (mng_uint16)(*(pScanline+2));
              iBGr16 = (mng_uint16)((mng_uint32)iBGr16 << 8) | iBGr16;
              iBGg16 = (mng_uint16)((mng_uint32)iBGg16 << 8) | iBGg16;
              iBGb16 = (mng_uint16)((mng_uint32)iBGb16 << 8) | iBGb16;
                                       /* now compose */
              MNG_COMPOSE16(iFGr16, iFGr16, iA16, iBGr16)
              MNG_COMPOSE16(iFGg16, iFGg16, iA16, iBGg16)
              MNG_COMPOSE16(iFGb16, iFGb16, iA16, iBGb16)
                                       /* and return the composed values */
              *pScanline     = (mng_uint8)(iFGr16 >> 8);
              *(pScanline+1) = (mng_uint8)(iFGg16 >> 8);
              *(pScanline+2) = (mng_uint8)(iFGb16 >> 8);
            }
          }

          pScanline += (pData->iColinc * 3);
          pDataline += 8;
        }
      }
      else
      {
        for (iX = pData->iSourcel + pData->iCol; iX < pData->iSourcer; iX += pData->iColinc)
        {
          iA8 = *(pDataline+3);        /* get alpha value */

          if (iA8)                     /* any opacity at all ? */
          {
            if (iA8 == 0xFF)           /* fully opaque ? */
            {                          /* then simply copy the values */
              *pScanline     = *pDataline;
              *(pScanline+1) = *(pDataline+1);
              *(pScanline+2) = *(pDataline+2);
            }
            else
            {                          /* do alpha composing */
              MNG_COMPOSE8 (*pScanline,     *pDataline,     iA8, *pScanline    )
              MNG_COMPOSE8 (*(pScanline+1), *(pDataline+1), iA8, *(pScanline+1))
              MNG_COMPOSE8 (*(pScanline+2), *(pDataline+2), iA8, *(pScanline+2))
            }
          }

          pScanline += (pData->iColinc * 3);
          pDataline += 4;
        }
      }
    }
  }

  check_update_region (pData);

#ifdef MNG_SUPPORT_TRACE
  MNG_TRACE (pData, MNG_FN_DISPLAY_RGB8, MNG_LC_END)
#endif

  return MNG_NOERROR;
}

/* ************************************************************************** */

mng_retcode display_rgba8 (mng_datap pData)
{
  mng_uint8p pScanline;
  mng_uint8p pDataline;
  mng_int32  iX;
  mng_uint16 iFGa16, iBGa16, iCa16;
  mng_uint8  iFGa8, iBGa8, iCa8;
  mng_uint16 iFGr16, iFGg16, iFGb16;
  mng_uint16 iBGr16, iBGg16, iBGb16;
  mng_uint16 iCr16, iCg16, iCb16;
  mng_uint8  iCr8, iCg8, iCb8;

#ifdef MNG_SUPPORT_TRACE
  MNG_TRACE (pData, MNG_FN_DISPLAY_RGBA8, MNG_LC_START)
#endif
                                       /* viewable row ? */
  if ((pData->iRow >= pData->iSourcet) && (pData->iRow < pData->iSourceb))
  {                                    /* address destination row */
    pScanline = (mng_uint8p)pData->fGetcanvasline (((mng_handle)pData),
                                                   pData->iRow + pData->iDestt -
                                                   pData->iSourcet);
                                       /* adjust destination row starting-point */
    pScanline = pScanline + (pData->iCol << 2) + (pData->iDestl << 2);
    pDataline = pData->pRGBArow;       /* address source row */

    if (pData->bIsRGBA16)              /* adjust source row starting-point */
      pDataline = pDataline + ((pData->iSourcel / pData->iColinc) << 3);
    else
      pDataline = pDataline + ((pData->iSourcel / pData->iColinc) << 2);

    if (pData->bIsOpaque)              /* forget about transparency ? */
    {
      if (pData->bIsRGBA16)            /* 16-bit input row ? */
      {
        for (iX = pData->iSourcel + pData->iCol; iX < pData->iSourcer; iX += pData->iColinc)
        {                              /* scale down by dropping the LSB */
          *pScanline     = *pDataline;
          *(pScanline+1) = *(pDataline+2);
          *(pScanline+2) = *(pDataline+4);
          *(pScanline+3) = *(pDataline+6);

          pScanline += (pData->iColinc << 2);
          pDataline += 8;
        }
      }
      else
      {
        for (iX = pData->iSourcel + pData->iCol; iX < pData->iSourcer; iX += pData->iColinc)
        {                              /* copy the values */
          *pScanline     = *pDataline;
          *(pScanline+1) = *(pDataline+1);
          *(pScanline+2) = *(pDataline+2);
          *(pScanline+3) = *(pDataline+3);

          pScanline += (pData->iColinc << 2);
          pDataline += 4;
        }
      }
    }
    else
    {
      if (pData->bIsRGBA16)            /* 16-bit input row ? */
      {
        for (iX = pData->iSourcel + pData->iCol; iX < pData->iSourcer; iX += pData->iColinc)
        {                              /* get alpha values */
          iFGa16 = mng_get_uint16 (pDataline+6);
          iBGa16 = (mng_uint16)(*(pScanline+3));
          iBGa16 = (mng_uint16)(iBGa16 << 8) | iBGa16;

          if (iFGa16)                  /* any opacity at all ? */
          {                            /* fully opaque or background fully transparent ? */
            if ((iFGa16 == 0xFFFF) || (iBGa16 == 0))
            {                          /* plain copy it */
              *pScanline     = *pDataline;
              *(pScanline+1) = *(pDataline+2);
              *(pScanline+2) = *(pDataline+4);
              *(pScanline+3) = *(pDataline+6);
            }
            else
            {
              if (iBGa16 == 0xFFFF)    /* background fully opaque ? */
              {                        /* get the proper values */
                iFGr16 = mng_get_uint16 (pDataline  );
                iFGg16 = mng_get_uint16 (pDataline+2);
                iFGb16 = mng_get_uint16 (pDataline+4);
                                       /* scale background up */
                iBGr16 = (mng_uint16)(*pScanline    );
                iBGg16 = (mng_uint16)(*(pScanline+1));
                iBGb16 = (mng_uint16)(*(pScanline+2));
                iBGr16 = (mng_uint16)((mng_uint32)iBGr16 << 8) | iBGr16;
                iBGg16 = (mng_uint16)((mng_uint32)iBGg16 << 8) | iBGg16;
                iBGb16 = (mng_uint16)((mng_uint32)iBGb16 << 8) | iBGb16;
                                       /* now compose */
                MNG_COMPOSE16(iFGr16, iFGr16, iFGa16, iBGr16)
                MNG_COMPOSE16(iFGg16, iFGg16, iFGa16, iBGg16)
                MNG_COMPOSE16(iFGb16, iFGb16, iFGa16, iBGb16)
                                       /* and return the composed values */
                *pScanline     = (mng_uint8)(iFGr16 >> 8);
                *(pScanline+1) = (mng_uint8)(iFGg16 >> 8);
                *(pScanline+2) = (mng_uint8)(iFGb16 >> 8);
                                       /* alpha remains fully opaque !!! */
              }
              else
              {                        /* scale background up */
                iBGr16 = (mng_uint16)(*pScanline    );
                iBGg16 = (mng_uint16)(*(pScanline+1));
                iBGb16 = (mng_uint16)(*(pScanline+2));
                iBGr16 = (mng_uint16)((mng_uint32)iBGr16 << 8) | iBGr16;
                iBGg16 = (mng_uint16)((mng_uint32)iBGg16 << 8) | iBGg16;
                iBGb16 = (mng_uint16)((mng_uint32)iBGb16 << 8) | iBGb16;
                                       /* let's blend */
                MNG_BLEND16 (mng_get_uint16 (pDataline  ),
                             mng_get_uint16 (pDataline+2),
                             mng_get_uint16 (pDataline+4), iFGa16,
                             iBGr16, iBGg16, iBGb16, iBGa16,
                             iCr16,  iCg16,  iCb16,  iCa16)
                                       /* and return the composed values */
                *pScanline     = (mng_uint8)(iCr16 >> 8);
                *(pScanline+1) = (mng_uint8)(iCg16 >> 8);
                *(pScanline+2) = (mng_uint8)(iCb16 >> 8);
                *(pScanline+3) = (mng_uint8)(iCa16 >> 8);
              }
            }
          }

          pScanline += (pData->iColinc << 2);
          pDataline += 8;
        }
      }
      else
      {
        for (iX = pData->iSourcel + pData->iCol; iX < pData->iSourcer; iX += pData->iColinc)
        {
          iFGa8 = *(pDataline+3);      /* get alpha values */
          iBGa8 = *(pScanline+3);

          if (iFGa8)                   /* any opacity at all ? */
          {                            /* fully opaque or background fully transparent ? */
            if ((iFGa8 == 0xFF) || (iBGa8 == 0))
            {                          /* then simply copy the values */
              *pScanline     = *pDataline;
              *(pScanline+1) = *(pDataline+1);
              *(pScanline+2) = *(pDataline+2);
              *(pScanline+3) = *(pDataline+3);
            }