static bool
colorconvert_impl (ImageBuf &R, const ImageBuf &A,
const ColorProcessor* processor, bool unpremult,
ROI roi, int nthreads)
{
if (nthreads != 1 && roi.npixels() >= 1000) {
// Possible multiple thread case -- recurse via parallel_image
ImageBufAlgo::parallel_image (
OIIO::bind(colorconvert_impl<Rtype,Atype>,
OIIO::ref(R), OIIO::cref(A), processor, unpremult,
_1 /*roi*/, 1 /*nthreads*/),
roi, nthreads);
return true;
}
// Serial case
int width = roi.width();
// Temporary space to hold one RGBA scanline
std::vector<float> scanline(width*4, 0.0f);
// Only process up to, and including, the first 4 channels. This
// does let us process images with fewer than 4 channels, which is
// the intent.
// FIXME: Instead of loading the first 4 channels, obey
// Rspec.alpha_channel index (but first validate that the
// index is set properly for normal formats)
int channelsToCopy = std::min (4, roi.nchannels());
// Walk through all data in our buffer. (i.e., crop or overscan)
// FIXME: What about the display window? Should this actually promote
// the datawindow to be union of data + display? This is useful if
// the color of black moves. (In which case non-zero sections should
// now be promoted). Consider the lin->log of a roto element, where
// black now moves to non-black.
float * dstPtr = NULL;
const float fltmin = std::numeric_limits<float>::min();
// If the processor has crosstalk, and we'll be using it, we should
// reset the channels to 0 before loading each scanline.
bool clearScanline = (channelsToCopy<4 &&
(processor->hasChannelCrosstalk() || unpremult));
ImageBuf::ConstIterator<Atype> a (A, roi);
ImageBuf::Iterator<Rtype> r (R, roi);
for (int k = roi.zbegin; k < roi.zend; ++k) {
for (int j = roi.ybegin; j < roi.yend; ++j) {
// Clear the scanline
if (clearScanline)
memset (&scanline[0], 0, sizeof(float)*scanline.size());
// Load the scanline
dstPtr = &scanline[0];
a.rerange (roi.xbegin, roi.xend, j, j+1, k, k+1);
for ( ; !a.done(); ++a, dstPtr += 4)
for (int c = 0; c < channelsToCopy; ++c)
dstPtr[c] = a[c];
// Optionally unpremult
if ((channelsToCopy >= 4) && unpremult) {
for (int i = 0; i < width; ++i) {
float alpha = scanline[4*i+3];
if (alpha > fltmin) {
scanline[4*i+0] /= alpha;
scanline[4*i+1] /= alpha;
scanline[4*i+2] /= alpha;
}
}
}
// Apply the color transformation in place
processor->apply (&scanline[0], width, 1, 4,
sizeof(float), 4*sizeof(float),
width*4*sizeof(float));
// Optionally premult
if ((channelsToCopy >= 4) && unpremult) {
for (int i = 0; i < width; ++i) {
float alpha = scanline[4*i+3];
if (alpha > fltmin) {
scanline[4*i+0] *= alpha;
scanline[4*i+1] *= alpha;
scanline[4*i+2] *= alpha;
}
}
}
// Store the scanline
dstPtr = &scanline[0];
r.rerange (roi.xbegin, roi.xend, j, j+1, k, k+1);
for ( ; !r.done(); ++r, dstPtr += 4)
for (int c = 0; c < channelsToCopy; ++c)
r[c] = dstPtr[c];
}
}
return true;
}
