// Set dst, over the region of interest, to be a resized version of the
// corresponding portion of src (mapping such that the "full" image
// window of each correspond to each other, regardless of resolution).
//
// The filter is used to weight the src pixels falling underneath it for
// each dst pixel. The caller may specify a reconstruction filter by name
// and width (expressed in pixels unts of the dst image), or ResizeFilter() will
// choose a reasonable default high-quality default filter (blackman-harris
// when upsizing, lanczos3 when downsizing) if the empty string is passed
// or if filterWidth is 0.
//
// The nthreads AlgoOpts specifies how many threads (potentially) may
// be used, but it's not a guarantee. If nthreads == 0, it will use
// the global OIIO attribute "nthreads". If nthreads == 1, it
// guarantees that it will not launch any new threads.
func ResizeFilter(dst, src *ImageBuf, filter string, filterWidth float32, opts ...AlgoOpts) error {
opt := flatAlgoOpts(opts)
c_filtname := C.CString(filter)
defer C.free(unsafe.Pointer(c_filtname))
ok := C.resize(dst.ptr, src.ptr, c_filtname, C.float(filterWidth), opt.ROI.validOrAllPtr(), C.int(opt.Threads))
if !bool(ok) {
return dst.LastError()
}
return nil
}
func (self *BlockFile) resize(size uint64) error {
if self.outstanding > 0 {
return errors.Errorf("cannot resize the file while there are outstanding pointers")
}
if !self.opened {
return errors.Errorf("File is not open")
}
if self.file == nil {
return self.anonResize(size)
}
var new_mmap unsafe.Pointer
errno := C.resize(self.mmap, &new_mmap, C.int(self.file.Fd()), C.size_t(size))
if errno != 0 {
return errors.Errorf("resize failed, %d", errno)
}
self.size = size
self.mmap = new_mmap
return nil
}