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Bug 125025: Animations use a lot of CPU, even when not visible. r=pavlov,

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sr=brendan.  Heavily optimizes all the bit-twiddling in mask generation
which was 1/2 of where the CPU time was going.


git-svn-id: svn://10.0.0.236/trunk@114860 18797224-902f-48f8-a5cc-f745e15eee43
This commit is contained in:
rjesup%wgate.com 2002-02-19 01:48:33 +00:00
parent c32eda13b3
commit a2ec5e88f6
1 changed files with 76 additions and 19 deletions
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95
mozilla/modules/libpr0n/src/imgContainer.cpp
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@ -747,38 +747,95 @@ void imgContainer::BuildCompositeMask(gfxIImageFrame *aCompositingFrame, gfxIIma
case gfxIFormats::RGB_A1:
case gfxIFormats::BGR_A1:
{
for(PRUint32 y=overlayYOffset, i=0;
i<PRUint32(heightOverlay) && y<PRUint32(heightComposite);
y++, i++) {
PRInt32 offset;
const PRUint32 width = PR_MIN(widthOverlay,(widthComposite-overlayXOffset));
const PRUint32 height = PR_MIN(heightOverlay,(heightComposite-overlayYOffset));
PRInt32 offset;
// Windows and OS/2 have the funky bottom up data storage we need to account for
#if defined(XP_WIN) || defined(XP_OS2)
offset = ((heightComposite - 1) * abprComposite) - y*abprComposite;
offset = ((heightComposite - 1) - overlayYOffset) * abprComposite;
#else
offset = y*abprComposite;
offset = overlayYOffset*abprComposite;
#endif
PRUint8* alphaLine = compositingAlphaData + offset;
PRUint8* alphaLine = compositingAlphaData + offset + (overlayXOffset>>3);
// Windows and OS/2 have the funky bottom up data storage we need to account for
#if defined(XP_WIN) || defined(XP_OS2)
offset = ((heightOverlay - 1) * abprOverlay) - i*abprOverlay;
offset = (heightOverlay - 1) * abprOverlay;
#else
offset = i*abprOverlay;
offset = 0;
#endif
PRUint8* overlayLine = overlayAlphaData + offset;
for (PRUint32 x=overlayXOffset, j=0;
j<PRUint32(widthOverlay) && x<PRUint32(widthComposite);
x++, j++) {
if (overlayLine[j>>3] & (1<<((7-j)&0x7)))
alphaLine[x>>3] |= 1<<((7-x)&0x7);
PRUint8* overlayLine = overlayAlphaData + offset;
/*
This is the number of pixels of offset between alpha and overlay
(the number of bits at the front of alpha to skip when starting
a row).
I.e:, for a mask_offset of 3:
(these are representations of bits)
overlay 'pixels': 76543210 hgfedcba
alpha: xxx76543 210hgfed ...
where 'x' is data already in alpha
the first 5 pixels of overlay are or'd into the low 5 bits of alpha
*/
PRUint8 mask_offset = (overlayXOffset & 0x7);
for(PRUint32 i=0; i < height; i++) {
PRUint8 pixels;
PRUint32 j;
// use locals to avoid keeping track of how much we need to add
// at the end of a line. we don't really need this since we may
// be able to calculate the ending offsets, but it's simpler and
// cheap.
PRUint8 *localOverlay = overlayLine;
PRUint8 *localAlpha = alphaLine;
for (j = width; j >= 8; j -= 8) {
// don't do in for(...) to avoid reference past end of buffer
pixels = *localOverlay++;
if (pixels == 0) {
// no bits to set - iterate and bump output pointer
localAlpha++;
}
else {
// for the last few bits of a line, we need to special-case it
if (mask_offset == 0) {
// simple case, no offset
*localAlpha++ |= pixels;
}
else {
*localAlpha++ |= (pixels >> mask_offset);
*localAlpha |= (pixels << (8U-mask_offset));
}
}
}
if (j != 0) {
// handle the end of the line, 1 to 7 pixels
pixels = *localOverlay++;
if (pixels != 0) {
// last few bits have to be handled more carefully if
// width is not a multiple of 8.
// set bits we don't want to change to 0
pixels = (pixels >> (8U-j)) << (8U-j);
*localAlpha++ |= (pixels >> mask_offset);
// don't touch this byte unless we have bits for it
if (j > (8U - mask_offset))
*localAlpha |= (pixels << (8U-mask_offset));
}
}
/// Windows and OS/2 have the funky bottom up data storage we need to account for
#if defined(XP_WIN) || defined(XP_OS2)
alphaLine -= abprComposite;
overlayLine -= abprOverlay;
#else
alphaLine += abprComposite;
overlayLine += abprOverlay;
#endif
}
}
break;
default:
break;