* Markus Neteler <[email protected]> [2016-08-27 15:37:35 +0200]:
On Sat, Aug 27, 2016 at 3:26 PM, Nikos Alexandris
<[email protected]> wrote:
While modifying i.rgb.his,
if (chroma == 0.0) {
saturation = 0.0;
/* undefined -- (how to) set to NULL? */
hue = 0.0;
rowbuffer[0][sample] = (FCELL)hue;
rowbuffer[1][sample] = (FCELL)intensity;
rowbuffer[2][sample] = (FCELL)saturation;
}
I'd like to set hue to NULL, whenever the condition is met. How do I do
that?
hue = NULL;
does not work.
No, it is done withRast_set_null_value()
Something like:
for (row = 0; row < nrows; row++) {
G_percent(row, nrows, 5);
for (col = 0; col < ncols; col++) {
cell_buf[col] = bas[SEG_INDEX(ba_seg, row, col)];
if (cell_buf[col] == 0)
Rast_set_null_value(&cell_buf[col], 1, CELL_TYPE);
Alright, that is: anything that `&cell_buf[col]` points to, set the
number of values `1` to NULL.
I need a few more examples to understand. What is the "number of values"?
Could it be a series of multiple values?
Nikos
}
Rast_put_row(basin_fd, cell_buf, CELL_TYPE);
}
(random example, taken from r.water.outlet/main.c)
HTH,
Markus
--
Nikos Alexandris | Remote Sensing & Geomatics
GPG Key Fingerprint 6F9D4506F3CA28380974D31A9053534B693C4FB3
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