reactos/subsystems/win32/win32k/dib/alphablend.c

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/*
* PROJECT: Win32 subsystem
* LICENSE: See COPYING in the top level directory
* FILE: subsystems/win32/win32k/dib/stretchblt.c
* PURPOSE: AlphaBlend implementation suitable for all bit depths
* PROGRAMMERS: Jérôme Gardou
*/
#include <win32k.h>
#define NDEBUG
#include <debug.h>
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 : val;
}
BOOLEAN
DIB_XXBPP_AlphaBlend(SURFOBJ* Dest, SURFOBJ* Source, RECTL* DestRect,
RECTL* SourceRect, CLIPOBJ* ClipRegion,
XLATEOBJ* ColorTranslation, BLENDOBJ* BlendObj)
{
INT DstX, DstY, SrcX, SrcY;
BLENDFUNCTION BlendFunc;
register NICEPIXEL32 DstPixel32;
register NICEPIXEL32 SrcPixel32;
UCHAR Alpha, SrcBpp = BitsPerFormat(Source->iBitmapFormat);
EXLATEOBJ* pexlo;
EXLATEOBJ exloSrcRGB, exloDstRGB, exloRGBSrc;
PFN_DIB_PutPixel pfnDibPutPixel = DibFunctionsForBitmapFormat[Dest->iBitmapFormat].DIB_PutPixel;
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 &&
SrcBpp != 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);
EXLATEOBJ_vInitialize(&exloDstRGB, pexlo->ppalDst, &gpalRGB, 0, 0, 0);
EXLATEOBJ_vInitialize(&exloRGBSrc, &gpalRGB, pexlo->ppalSrc, 0, 0, 0);
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 ;
DstPixel32.ul = DIB_GetSource(Dest, DstX, DstY, &exloDstRGB.xlo);
DstPixel32.col.red = Clamp8((DstPixel32.col.red * (255 - Alpha)) / 255 + SrcPixel32.col.red) ;
DstPixel32.col.green = Clamp8((DstPixel32.col.green * (255 - Alpha)) / 255 + SrcPixel32.col.green) ;
DstPixel32.col.blue = Clamp8((DstPixel32.col.blue * (255 - Alpha)) / 255 + SrcPixel32.col.blue) ;
DstPixel32.ul = XLATEOBJ_iXlate(&exloRGBSrc.xlo, DstPixel32.ul);
pfnDibPutPixel(Dest, DstX, DstY, XLATEOBJ_iXlate(ColorTranslation, DstPixel32.ul));
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(&exloDstRGB);
EXLATEOBJ_vCleanup(&exloRGBSrc);
EXLATEOBJ_vCleanup(&exloSrcRGB);
return TRUE;
}