C++ ConstIterator::pos方法代码示例

static int
action_flip (int argc, const char *argv[])
{
    if (ot.postpone_callback (1, action_flip, argc, argv))
        return 0;

    ot.read ();
    ImageRecRef A = ot.pop();
    ot.push (new ImageRec (*A, ot.allsubimages ? -1 : 0,
                           ot.allsubimages ? -1 : 0, true, false));

    int subimages = ot.curimg->subimages();
    for (int s = 0;  s < subimages;  ++s) {
        int miplevels = ot.curimg->miplevels(s);
        for (int m = 0;  m < miplevels;  ++m) {
            const ImageBuf &Aib ((*A)(s,m));
            ImageBuf &Rib ((*ot.curimg)(s,m));
            ImageBuf::ConstIterator<float> a (Aib);
            ImageBuf::Iterator<float> r (Rib);
            int nchans = Rib.nchannels();
            int firstscanline = Rib.ymin();
            int lastscanline = Rib.ymax();
            for ( ; ! r.done(); ++r) {
                a.pos (r.x(), lastscanline - (r.y() - firstscanline));
                for (int c = 0;  c < nchans;  ++c)
                    r[c] = a[c];
            }
        }
    }
             
    return 0;
}

static int
action_sub (int argc, const char *argv[])
{
    if (ot.postpone_callback (2, action_sub, argc, argv))
        return 0;

    ImageRecRef B (ot.pop());
    ImageRecRef A (ot.pop());
    ot.read (A);
    ot.read (B);
    ot.push (new ImageRec (*A, ot.allsubimages ? -1 : 0,
                           ot.allsubimages ? -1 : 0, true, false));

    int subimages = ot.curimg->subimages();
    for (int s = 0;  s < subimages;  ++s) {
        int miplevels = ot.curimg->miplevels(s);
        for (int m = 0;  m < miplevels;  ++m) {
            const ImageBuf &Aib ((*A)(s,m));
            const ImageBuf &Bib ((*B)(s,m));
            if (! same_size (Aib, Bib)) {
                // FIXME: some day, there should be options of combining
                // differing images somehow.
                std::cerr << "oiiotool: " << argv[0] << " could not combine images of differing sizes\n";
                continue;
            }
            ImageBuf &Rib ((*ot.curimg)(s,m));
            ImageBuf::ConstIterator<float> a (Aib);
            ImageBuf::ConstIterator<float> b (Bib);
            ImageBuf::Iterator<float> r (Rib);
            int nchans = Rib.nchannels();
            for ( ; ! r.done(); ++r) {
                a.pos (r.x(), r.y());
                b.pos (r.x(), r.y());
                for (int c = 0;  c < nchans;  ++c)
                    r[c] = a[c] - b[c];
            }
        }
    }
             
    return 0;
}

static bool
flop_ (ImageBuf &dst, const ImageBuf &src, ROI roi, int nthreads)
{
    ImageBuf::ConstIterator<S, D> s (src, roi);
    ImageBuf::Iterator<D, D> d (dst, roi);
    for ( ; ! d.done(); ++d) {
        s.pos (roi.xend-1 - (d.x() - roi.xbegin), d.y(), d.z());
        for (int c = roi.chbegin; c < roi.chend; ++c)
            d[c] = s[c];
    }
    return true;
}

static bool
flip_ (ImageBuf &dst, const ImageBuf &src, ROI dst_roi, int nthreads)
{
    ROI src_roi_full = src.roi_full();
    ROI dst_roi_full = dst.roi_full();
    ImageBuf::ConstIterator<S, D> s (src);
    ImageBuf::Iterator<D, D> d (dst, dst_roi);
    for ( ; ! d.done(); ++d) {
        int yy = d.y() - dst_roi_full.ybegin;
        s.pos (d.x(), src_roi_full.yend-1 - yy, d.z());
        for (int c = dst_roi.chbegin; c < dst_roi.chend; ++c)
            d[c] = s[c];
    }
    return true;
}

static bool
convolve_ (ImageBuf &dst, const ImageBuf &src, const ImageBuf &kernel,
           bool normalize, ROI roi, int nthreads)
{
    if (nthreads != 1 && roi.npixels() >= 1000) {
        // Lots of pixels and request for multi threads? Parallelize.
        ImageBufAlgo::parallel_image (
            boost::bind(convolve_<DSTTYPE,SRCTYPE>, boost::ref(dst),
                        boost::cref(src), boost::cref(kernel), normalize,
                        _1 /*roi*/, 1 /*nthreads*/),
            roi, nthreads);
        return true;
    }

    // Serial case

    float scale = 1.0f;
    if (normalize) {
        scale = 0.0f;
        for (ImageBuf::ConstIterator<float> k (kernel); ! k.done(); ++k)
            scale += k[0];
        scale = 1.0f / scale;
    }

    float *sum = ALLOCA (float, roi.chend);
    ROI kroi = get_roi (kernel.spec());
    ImageBuf::Iterator<DSTTYPE> d (dst, roi);
    ImageBuf::ConstIterator<SRCTYPE> s (src, roi, ImageBuf::WrapClamp);
    for ( ; ! d.done();  ++d) {

        for (int c = roi.chbegin; c < roi.chend; ++c)
            sum[c] = 0.0f;

        for (ImageBuf::ConstIterator<float> k (kernel, kroi); !k.done(); ++k) {
            float kval = k[0];
            s.pos (d.x() + k.x(), d.y() + k.y(), d.z() + k.z());
            for (int c = roi.chbegin; c < roi.chend; ++c)
                sum[c] += kval * s[c];
        }
        
        for (int c = roi.chbegin; c < roi.chend; ++c)
            d[c] = scale * sum[c];
    }

    return true;
}

// DEPRECATED version
bool
ImageBufAlgo::add (ImageBuf &dst, const ImageBuf &A, const ImageBuf &B,
                   int options)
{
    // Sanity checks
    
    // dst must be distinct from A and B
    if ((const void *)&A == (const void *)&dst ||
        (const void *)&B == (const void *)&dst) {
        dst.error ("destination image must be distinct from source");
        return false;
    }
    
    // all three images must have the same number of channels
    if (A.spec().nchannels != B.spec().nchannels) {
        dst.error ("channel number mismatch: %d vs. %d", 
                   A.spec().nchannels, B.spec().nchannels);
        return false;
    }
    
    // If dst has not already been allocated, set it to the right size,
    // make it unconditinally float
    if (! dst.pixels_valid()) {
        ImageSpec dstspec = A.spec();
        dstspec.set_format (TypeDesc::TypeFloat);
        dst.alloc (dstspec);
    }
    // Clear dst pixels if instructed to do so
    if (options & ADD_CLEAR_DST) {
        zero (dst);
    }
      
    ASSERT (A.spec().format == TypeDesc::FLOAT &&
            B.spec().format == TypeDesc::FLOAT &&
            dst.spec().format == TypeDesc::FLOAT);
    
    ImageBuf::ConstIterator<float,float> a (A);
    ImageBuf::ConstIterator<float,float> b (B);
    ImageBuf::Iterator<float> d (dst);
    int nchannels = A.nchannels();
    // Loop over all pixels in A
    for ( ; a.valid();  ++a) {  
        // Point the iterators for B and dst to the corresponding pixel
        if (options & ADD_RETAIN_WINDOWS) {
            b.pos (a.x(), a.y());
        } else {
            // ADD_ALIGN_WINDOWS: make B line up with A
            b.pos (a.x()-A.xbegin()+B.xbegin(), a.y()-A.ybegin()+B.ybegin());
        }
        d.pos (a.x(), b.y());
        
        if (! b.valid() || ! d.valid())
            continue;   // Skip pixels that don't align
        
        // Add the pixel
        for (int c = 0;  c < nchannels;  ++c)
              d[c] = a[c] + b[c];
    }
    
    return true;
}

static bool
resample_ (ImageBuf &dst, const ImageBuf &src, bool interpolate,
           ROI roi, int nthreads)
{
    if (nthreads != 1 && roi.npixels() >= 1000) {
        // Lots of pixels and request for multi threads? Parallelize.
        ImageBufAlgo::parallel_image (
            boost::bind(resample_<DSTTYPE,SRCTYPE>, boost::ref(dst),
                        boost::cref(src), interpolate,
                        _1 /*roi*/, 1 /*nthreads*/),
            roi, nthreads);
        return true;
    }

    // Serial case

    const ImageSpec &srcspec (src.spec());
    const ImageSpec &dstspec (dst.spec());
    int nchannels = src.nchannels();

    // Local copies of the source image window, converted to float
    float srcfx = srcspec.full_x;
    float srcfy = srcspec.full_y;
    float srcfw = srcspec.full_width;
    float srcfh = srcspec.full_height;

    float dstfx = dstspec.full_x;
    float dstfy = dstspec.full_y;
    float dstfw = dstspec.full_width;
    float dstfh = dstspec.full_height;
    float dstpixelwidth = 1.0f / dstfw;
    float dstpixelheight = 1.0f / dstfh;
    float *pel = ALLOCA (float, nchannels);

    ImageBuf::Iterator<DSTTYPE> out (dst, roi);
    ImageBuf::ConstIterator<SRCTYPE> srcpel (src);
    for (int y = roi.ybegin;  y < roi.yend;  ++y) {
        // s,t are NDC space
        float t = (y-dstfy+0.5f)*dstpixelheight;
        // src_xf, src_xf are image space float coordinates
        float src_yf = srcfy + t * srcfh - 0.5f;
        // src_x, src_y are image space integer coordinates of the floor
        int src_y;
        (void) floorfrac (src_yf, &src_y);
        for (int x = roi.xbegin;  x < roi.xend;  ++x) {
            float s = (x-dstfx+0.5f)*dstpixelwidth;
            float src_xf = srcfx + s * srcfw - 0.5f;
            int src_x;
            (void) floorfrac (src_xf, &src_x);

            if (interpolate) {
                src.interppixel (src_xf, src_yf, pel);
                for (int c = roi.chbegin; c < roi.chend; ++c)
                    out[c] = pel[c];
            } else {
                srcpel.pos (src_x, src_y, 0);
                for (int c = roi.chbegin; c < roi.chend; ++c)
                    out[c] = srcpel[c];
            }
            ++out;
        }
    }

    return true;
}

//.........这里部分代码省略.........
        // If using separable filters, our vertical set of filter tap
        // weights will be the same for the whole scanline we're on.  Just
        // compute and normalize them once.
        float totalweight_y = 0.0f;
        if (separable) {
            for (int j = 0;  j < ytaps;  ++j) {
                float w = filter->yfilt (yratio * (j-radj-(src_yf_frac-0.5f)));
                yfiltval[j] = w;
                totalweight_y += w;
            }
            for (int i = 0;  i <= ytaps;  ++i)
                yfiltval[i] /= totalweight_y;
        }

        for (int x = roi.xbegin;  x < roi.xend;  ++x) {
            float s = (x-dstfx+0.5f)*dstpixelwidth;
            float src_xf = srcfx + s * srcfw;
            int src_x;
            float src_xf_frac = floorfrac (src_xf, &src_x);
            for (int c = 0;  c < nchannels;  ++c)
                pel[c] = 0.0f;
            if (separable) {
                // Cache and normalize the horizontal filter tap weights
                // just once for this (x,y) position, reuse for all vertical
                // taps.
                float totalweight_x = 0.0f;
                for (int i = 0;  i < xtaps;  ++i) {
                    float w = filter->xfilt (xratio * (i-radi-(src_xf_frac-0.5f)));
                    xfiltval[i] = w;
                    totalweight_x += w;
                }

                if (totalweight_x != 0.0f) {
                    for (int i = 0;  i < xtaps;  ++i)  // normalize x filter
                        xfiltval[i] /= totalweight_x;  // weights
                    ImageBuf::ConstIterator<SRCTYPE> srcpel (src, src_x-radi, src_x+radi+1,
                                                             src_y-radj, src_y+radj+1,
                                                             0, 1, ImageBuf::WrapClamp);
                    for (int j = -radj;  j <= radj;  ++j) {
                        float wy = yfiltval[j+radj];
                        if (wy == 0.0f) {
                            // 0 weight for this y tap -- move to next line
                            srcpel.pos (srcpel.x(), srcpel.y()+1, srcpel.z());
                            continue;
                        }
                        for (int i = 0;  i < xtaps; ++i, ++srcpel) {
                            float w = wy * xfiltval[i];
                            for (int c = 0;  c < nchannels;  ++c)
                                pel[c] += w * srcpel[c];
                        }
                    }
                }
                // Copy the pixel value (already normalized) to the output.
                DASSERT (out.x() == x && out.y() == y);
                if (totalweight_y == 0.0f) {
                    // zero it out
                    for (int c = 0;  c < nchannels;  ++c)
                        out[c] = 0.0f;
                } else {
                    for (int c = 0;  c < nchannels;  ++c)
                        out[c] = pel[c];
                }
            } else {
                // Non-separable
                float totalweight = 0.0f;
                ImageBuf::ConstIterator<SRCTYPE> srcpel (src, src_x-radi, src_x+radi+1,
                                                       src_y-radi, src_y+radi+1,
                                                       0, 1, ImageBuf::WrapClamp);
                for (int j = -radj;  j <= radj;  ++j) {
                    for (int i = -radi;  i <= radi;  ++i, ++srcpel) {
                        float w = (*filter)(xratio * (i-(src_xf_frac-0.5f)),
                                            yratio * (j-(src_yf_frac-0.5f)));
                        totalweight += w;
                        if (w == 0.0f)
                            continue;
                        DASSERT (! srcpel.done());
                        for (int c = 0;  c < nchannels;  ++c)
                            pel[c] += w * srcpel[c];
                    }
                }
                DASSERT (srcpel.done());
                // Rescale pel to normalize the filter and write it to the
                // output image.
                DASSERT (out.x() == x && out.y() == y);
                if (totalweight == 0.0f) {
                    // zero it out
                    for (int c = 0;  c < nchannels;  ++c)
                        out[c] = 0.0f;
                } else {
                    for (int c = 0;  c < nchannels;  ++c)
                        out[c] = pel[c] / totalweight;
                }
            }

            ++out;
        }
    }

    return true;
}