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Simplify ops that would use the alpha channel when an alpha channel is

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always 1.0, and short circuit PictOpDst for good measure.
This commit is contained in:
Eric Anholt 2006-02-12 20:53:35 +00:00
parent 5f45776ef3
commit 34d0b9228f
2 changed files with 97 additions and 0 deletions
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8
ChangeLog
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@ -1,3 +1,11 @@
2006-02-12 Eric Anholt <anholt@FreeBSD.org>
reviewed by: keithp (in principle)
* render/picture.c: (ReduceCompositeOp), (CompositePicture):
Simplify ops that would use the alpha channel when an alpha channel is
always 1.0, and short circuit PictOpDst for good measure.
2006-02-12 Eric Anholt <anholt@FreeBSD.org>
* hw/kdrive/linux/Makefile.am:

89
render/picture.c
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@ -1657,6 +1657,90 @@ FreePictFormat (pointer pPictFormat,
return Success;
}
/**
* ReduceCompositeOp is used to choose simpler ops for cases where alpha
* channels are always one and so math on the alpha channel per pixel becomes
* unnecessary. It may also avoid destination reads sometimes if apps aren't
* being careful to avoid these cases.
*/
static Bool
ReduceCompositeOp (CARD8 op, PicturePtr pSrc, PicturePtr pMask, PicturePtr pDst)
{
/* Deal with simplifications where the source alpha is always 1. */
if (PICT_FORMAT_COLOR(pSrc->format) &&
PICT_FORMAT_A(pSrc->format) == 0 && pSrc->alphaMap == NULL &&
pMask == NULL)
{
switch (op) {
case PictOpOver:
op = PictOpSrc;
break;
case PictOpInReverse:
op = PictOpDst;
break;
case PictOpOutReverse:
op = PictOpClear;
break;
case PictOpAtop:
op = PictOpIn;
break;
case PictOpAtopReverse:
op = PictOpOverReverse;
break;
case PictOpXor:
op = PictOpOut;
break;
default:
break;
}
}
/* Deal with simplifications when the destination alpha is always 1 */
if (PICT_FORMAT_COLOR(pDst->format) &&
PICT_FORMAT_A(pDst->format) == 0 && pDst->alphaMap == NULL)
{
switch (op) {
case PictOpOverReverse:
op = PictOpDst;
break;
case PictOpIn:
op = PictOpSrc;
break;
case PictOpOut:
op = PictOpClear;
break;
case PictOpAtop:
op = PictOpOver;
break;
case PictOpXor:
op = PictOpOutReverse;
break;
default:
break;
}
}
/* Reduce some con/disjoint ops to the basic names. */
switch (op) {
case PictOpDisjointClear:
case PictOpConjointClear:
op = PictOpClear;
break;
case PictOpDisjointSrc:
case PictOpConjointSrc:
op = PictOpSrc;
break;
case PictOpDisjointDst:
case PictOpConjointDst:
op = PictOpDst;
break;
default:
break;
}
return op;
}
void
CompositePicture (CARD8 op,
PicturePtr pSrc,
@ -1677,6 +1761,11 @@ CompositePicture (CARD8 op,
if (pMask)
ValidatePicture (pMask);
ValidatePicture (pDst);
op = ReduceCompositeOp (op, pSrc, pMask, pDst);
if (op == PictOpDst)
return;
(*ps->Composite) (op,
pSrc,
pMask,