1. Introduction
The library provides a type Npic_image for handling bitmap images in
memory. Choice is given for dimension (2 to 6), pixels type (char, long,
double, 4 shorts), pixel access (linear or cartesian coordinates) ; an external
border can be added for simplifying programs working with masks (distance
transforms, convolutions, etc).
Npic provides the NPZ compressed file format (extension .npz)
which allows to store any Npic_image to disk.
Functions are also given for other formats, such as the 3D VOL format
or the 2D PGM format; the files can be read or write directly gzip compressed,
which save a lot of disk space!
A set of command-line tools are given in directory
tools/, which you can call in shell scripts.
Note: this document is not finished, it will be improved a.s.a.p.
#include <npic.h>
int main ()
{
int x, y;
Npic_image *np1;
Npic_image_2l *p1;
/* Create a 2L image = 2D image with signed long pixels (4 bytes). height
is ymax=12, width is xmax=20, external borders are ybor=0, xbor=0. */
np1 = NpicCreateImage_2l (12, 20, 0, 0);
if (np1 == NULL) exit (1);
/* Assign values to pixels */
p1 = NpicCastImage (np1);
for (y = 0; y < p1->ymax; y++)
for (x = 0; x < p1->xmax; x++)
p1->pix[y][x] = (x + y) % 16;
/* Print image */
NpicPrintImage (np1);
/* Destroy image */
NpicDestroyImage (np1);
exit(0);
}
For compiling the previous example demo1.c, type :
gcc demo1.c -o demo1 `/npic_path/npic-cfg --cflags --libs`
` ` allows to recover the options
which depend from Npic installation; you just have to replace
/npic_path with the actual absolute path. Another way for compiling is to use the following sh script :
#! /bin/sh
p=/npic_path # replace with actual path
f=`basename $1 .c`
gcc $f.c -o $f `$p/npic-cfg --cflags --libs`
ncomp", save, type "chmod +x ncomp".
For compiling a file "ex.c", type "./ncomp ex.c" or
"./ncomp ex".
For compiling a file and run the program if the compilation succeed,
type "./ncomp ex.c && ex".
Now here is a basic Makefile; one includes the Npic configuration file
/npic_path/.config, where the usefull variables are declared,
in particular, $(CC), $(NPIC_CFLAGS) and $(NPIC_LIBS).
Beware, be sure that the indented lines start with a [TAB].
include /npic_path/.config # replace with actual path
.c.o :
$(CC) -c $(NPIC_CFLAGS) $*.c
ex1 : ex1.o
$(CC) -o $@ $@.o $(NPIC_LIBS)
Finally, the following Makefile allows to compile several programs and to clean up the directory.
include /npic_path/.config # replace with actual path
.c.o :
$(CC) -c $(NPIC_CFLAGS) $*.c
# Add here the name of your programs
EXECS = ex1 ex2 ex3
help ::
@echo "Options of make : help all clean distclean $(EXECS)"
# Add here the dependencies
ex1 : ex1.o
ex2 : ex2.o
ex3 : ex3.o
all :: $(EXECS)
$(EXECS) :
$(CC) -o $@ $@.o $(NPIC_LIBS)
clean ::
\rm -f *.o core
distclean :: clean
\rm -f $(EXECS)
#include <npic.h>
void my_draw (Npic_image *np1)
{
if (NpicImageIsOK (np1, __func__) != NPIC_SUCCESS)
return;
switch (np1->type) {
case NPIC_IMAGE_2L : {
Npic_image_2l *p1 = NpicCastImage (np1);
int x, y;
for (y = 0; y < p1->ymax; y++)
for (x = 0; x < p1->xmax; x++)
p1->pix[y][x] = (x + y) % 16;
return;
}
case NPIC_IMAGE_3L : {
Npic_image_3l *p1 = NpicCastImage (np1);
int x, y, z;
for (z = 0; z < p1->zmax; z++)
for (y = 0; y < p1->ymax; y++)
for (x = 0; x < p1->xmax; x++)
p1->pix[z][y][x] = (x + y + z) % 16;
return;
}
default :
np1->gen.ok = NpicError (__func__, NPIC_ERR_UNEX_NPIC, "");
}
}
int main ()
{
Npic_image *np1;
/* Create a 2L image = 2D image with signed long pixels (4 bytes). height
is ymax=12, width is xmax=20, external borders are ybor=0, xbor=0. */
np1 = NpicCreateImage_2l (12, 20, 0, 0);
if (np1 == NULL) exit (1);
/* Assign values to pixels */
my_draw (np1);
/* Print image */
NpicPrintImage (np1);
/* Destroy image */
NpicDestroyImage (np1);
exit(0);
}
#include <npic.h>
void my_draw (Npic_image *np2, Npic_image *np1, double c1, double c2)
{
if (NpicImageIsOK_DS1 (np2, np1, __func__) != NPIC_SUCCESS)
return;
if (NpicSameImage (np2, np1, NPIC_TYPE | NPIC_SIZE) != NPIC_SUCCESS) {
np2->gen.ok = NpicError (__func__, NPIC_ERR_INCOMPAT, "");
return;
}
switch (np2->type) {
case NPIC_IMAGE_2L : {
Npic_image_2l *p2 = NpicCastImage (np2),
*p1 = NpicCastImage (np1);
int x, y;
for (y = 0; y < p2->ymax; y++)
for (x = 0; x < p2->xmax; x++)
p2->pix[y][x] = p1->pix[y][x]*c1 + c2;
return;
}
case NPIC_IMAGE_3L : {
Npic_image_3l *p2 = NpicCastImage (np2),
*p1 = NpicCastImage (np1);
int x, y, z;
for (z = 0; z < p2->zmax; z++)
for (y = 0; y < p2->ymax; y++)
for (x = 0; x < p2->xmax; x++)
p2->pix[z][y][x] = p1->pix[z][y][x]*c1 + c2;
return;
}
default :
np2->gen.ok = NpicError (__func__, NPIC_ERR_UNEX_NPIC, "");
}
}
int main ()
{
Npic_image *np1, *np2;
Npic_image_2l *p1;
int x, y;
/* Create a 2L image = 2D image with signed long pixels (4 bytes). height
is ymax=12, width is xmax=20, external borders are ybor=0, xbor=0. */
np1 = NpicCreateImage_2l (12, 20, 0, 0);
if (np1 == NULL) exit (1);
/* Assign values to pixels */
p1 = NpicCastImage (np1);
for (y = 0; y < p1->ymax; y++)
for (x = 0; x < p1->xmax; x++)
p1->pix[y][x] = (x + y) % 16;
/* Create a second image with same size and type than np1 */
np2 = NpicDupImage (np1);
if (np2 == NULL) exit (1);
/* Compute np2 pixels values */
my_draw (np2, np1, 2, 4);
/* Print image */
NpicPrintImage (np2);
/* Destroy image */
NpicDestroyImage (np1);
NpicDestroyImage (np2);
exit(0);
}