ref: 317cb407d207055980e3b700e5dc5a5178b0672b
parent: 5961a8b6d2f95e29c0b7b0b450eb988763b12c40
author: rodri <rgl@antares-labs.eu>
date: Sat Apr 26 17:53:52 EDT 2025
add image processing tools
--- /dev/null
+++ b/image/add.c
@@ -1,0 +1,58 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <memdraw.h>
+
+static void
+usage(void)
+{+ fprint(2, "usage: %s img1 img2\n", argv0);
+ exits(nil);
+}
+
+void
+main(int argc, char *argv[])
+{+ Memimage *img1, *img2;
+ uchar *p1, *p2;
+ uchar *p1e;
+ int fd;
+
+ ARGBEGIN{+ default: usage();
+ }ARGEND;
+ if(argc != 2)
+ usage();
+
+ fd = open(argv[0], OREAD);
+ if(fd < 0)
+ sysfatal("open: %r");+ img1 = readmemimage(fd);
+ if(img1 == nil)
+ sysfatal("readmemimage: %r");+ close(fd);
+
+ fd = open(argv[1], OREAD);
+ if(fd < 0)
+ sysfatal("open: %r");+ img2 = readmemimage(fd);
+ if(img2 == nil)
+ sysfatal("readmemimage: %r");+ close(fd);
+
+ if(img1->chan != img2->chan || !eqrect(img1->r, img2->r))
+ sysfatal("images shapes differ");+
+ p1 = img1->data->bdata;
+ p2 = img2->data->bdata;
+ p1e = p1 + Dx(img1->r)*Dy(img1->r)*img1->nchan;
+ while(p1 < p1e)
+ *p1++ += *p2++;
+
+ if(writememimage(1, img1) < 0)
+ sysfatal("writememimage: %r");+
+ freememimage(img2);
+ freememimage(img1);
+ exits(nil);
+}
--- /dev/null
+++ b/image/convolution.c
@@ -1,0 +1,212 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include <draw.h>
+#include <memdraw.h>
+
+#define min(a,b) ((a)<(b)?(a):(b))
+#define max(a,b) ((a)>(b)?(a):(b))
+#define clamp(a,b,c) min(max(a,b),c)
+
+static int dim;
+
+static void
+fprintm(int fd, double *m, int dim)
+{+ int i, j;
+
+ for(j = 0; j < dim; j++)
+ for(i = 0; i < dim; i++)
+ fprint(fd, "%g%c", m[j*dim+i], i == dim-1? '\n': '\t');
+}
+
+static double *
+readkernel(int fd)
+{+ Biobuf *bin;
+ double *kern;
+ char *line, *f[10];
+ int nf, i, j;
+
+ bin = Bfdopen(fd, OREAD);
+ if(bin == nil)
+ sysfatal("Bfdopen: %r");+ do{+ line = Brdline(bin, '\n');
+ if(line == nil)
+ sysfatal("Brdline: %r");+ dim = tokenize(line, f, nelem(f));
+ }while(dim < 1);
+ kern = malloc(dim*dim*sizeof(double));
+ if(kern == nil)
+ sysfatal("malloc: %r");+ for(j = i = 0; i < dim; i++)
+ kern[j*dim+i] = strtod(f[i], nil);
+ j++;
+
+ while((line = Brdline(bin, '\n')) != nil){+ if((nf = tokenize(line, f, nelem(f))) < 1)
+ continue;
+ if(nf != dim)
+ sysfatal("expected a %dx%d matrix", dim, dim);+ for(i = 0; i < dim; i++)
+ kern[j*dim+i] = strtod(f[i], nil);
+ j++;
+ }
+ Bterm(bin);
+
+ if(j != dim)
+ sysfatal("expected a %dx%d matrix", dim, dim);+
+ return kern;
+}
+
+static void
+normalize(double *k, int dim)
+{+ double avg;
+ int i, j;
+
+ avg = 0;
+ for(j = 0; j < dim; j++)
+ for(i = 0; i < dim; i++)
+ avg += k[j*dim+i];
+ avg /= dim*dim;
+ for(j = 0; j < dim; j++)
+ for(i = 0; i < dim; i++)
+ k[j*dim+i] /= avg;
+}
+
+static double *
+reverse(double *k, int dim)
+{+ double *ck;
+ int i, j;
+
+ ck = malloc(dim*dim*sizeof(double));
+ if(ck == nil)
+ sysfatal("malloc: %r");+
+ for(j = 0; j < dim; j++)
+ for(i = 0; i < dim; i++)
+ ck[j*dim+i] = k[(dim-j-1)*dim+(dim-i-1)];
+ return ck;
+}
+
+static void
+modulate(double *d, double *s, int dim)
+{+ int i, j;
+
+ for(j = 0; j < dim; j++)
+ for(i = 0; i < dim; i++)
+ d[j*dim+i] *= s[j*dim+i];
+}
+
+static double
+convolve(double *d, double *s, int dim)
+{+ int i, j;
+ double r;
+
+ modulate(d, s, dim);
+ r = 0;
+ for(j = 0; j < dim; j++)
+ for(i = 0; i < dim; i++)
+ r += d[j*dim+i];
+ return r;
+}
+
+static uchar
+sample(Memimage *i, Point p, int off)
+{+ if(p.x < i->r.min.x || p.y < i->r.min.y
+ || p.x >= i->r.max.x || p.y >= i->r.max.y)
+ return 0; /* edge handler: constant */
+ return *(byteaddr(i, p) + off);
+}
+
+static void
+imgconvolution(Memimage *d, Memimage *s, double *k, int dim)
+{+ double **im;
+ Rectangle imr;
+ Point imc, p, cp;
+ int i;
+
+ im = malloc(d->nchan*sizeof(double*));
+ if(im == nil)
+ sysfatal("malloc: %r");+ for(i = 0; i < d->nchan; i++){+ im[i] = malloc(dim*dim*sizeof(double));
+ if(im[i] == nil)
+ sysfatal("malloc: %r");+ }
+
+ imr = Rect(0,0,dim,dim);
+ imc = Pt(dim/2, dim/2);
+
+ for(p.y = s->r.min.y; p.y < s->r.max.y; p.y++)
+ for(p.x = s->r.min.x; p.x < s->r.max.x; p.x++){+ for(cp.y = imr.min.y; cp.y < imr.max.y; cp.y++)
+ for(cp.x = imr.min.x; cp.x < imr.max.x; cp.x++){+ for(i = 0; i < d->nchan; i++){+ im[i][cp.y*dim + cp.x] = sample(s, addpt(p, subpt(cp, imc)), i);
+ }
+ }
+ for(i = 0; i < d->nchan; i++)
+ *(byteaddr(d, p) + i) = convolve(im[i], k, dim);
+ }
+
+ for(i = 0; i < d->nchan; i++)
+ free(im[i]);
+ free(im);
+}
+
+
+static void
+usage(void)
+{+ fprint(2, "usage: %s imgfile\n", argv0);
+ exits("usage");+}
+
+void
+main(int argc, char *argv[])
+{+ Memimage *in, *out;
+ double *kern, *ckern;
+ int fd;
+
+ ARGBEGIN{+ default: usage();
+ }ARGEND;
+ if(argc != 1)
+ usage();
+
+ kern = readkernel(0);
+ ckern = reverse(kern, dim);
+ free(kern);
+ kern = ckern;
+
+ fd = open(argv[0], OREAD);
+ if(fd < 0)
+ sysfatal("open: %r");+ in = readmemimage(fd);
+ if(in == nil)
+ sysfatal("readmemimage: %r");+ close(fd);
+
+ out = allocmemimage(in->r, in->chan);
+ if(out == nil)
+ sysfatal("allocmemimage: %r");+
+ imgconvolution(out, in, kern, dim);
+ if(writememimage(1, out) < 0)
+ sysfatal("writememimage: %r");+
+ freememimage(out);
+ freememimage(in);
+ free(kern);
+ exits(nil);
+}
--- /dev/null
+++ b/image/mkfile
@@ -1,0 +1,10 @@
+</$objtype/mkfile
+
+BIN=$home/bin/$objtype
+TARG=\
+ convolution\
+ add\
+ sub\
+ sobel\
+
+</sys/src/cmd/mkmany
--- /dev/null
+++ b/image/sobel.c
@@ -1,0 +1,58 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <memdraw.h>
+
+static void
+usage(void)
+{+ fprint(2, "usage: %s img1 img2\n", argv0);
+ exits(nil);
+}
+
+void
+main(int argc, char *argv[])
+{+ Memimage *img1, *img2;
+ uchar *p1, *p2;
+ uchar *p1e;
+ int fd;
+
+ ARGBEGIN{+ default: usage();
+ }ARGEND;
+ if(argc != 2)
+ usage();
+
+ fd = open(argv[0], OREAD);
+ if(fd < 0)
+ sysfatal("open: %r");+ img1 = readmemimage(fd);
+ if(img1 == nil)
+ sysfatal("readmemimage: %r");+ close(fd);
+
+ fd = open(argv[1], OREAD);
+ if(fd < 0)
+ sysfatal("open: %r");+ img2 = readmemimage(fd);
+ if(img2 == nil)
+ sysfatal("readmemimage: %r");+ close(fd);
+
+ if(img1->chan != img2->chan || !eqrect(img1->r, img2->r))
+ sysfatal("images shapes differ");+
+ p1 = img1->data->bdata;
+ p2 = img2->data->bdata;
+ p1e = p1 + Dx(img1->r)*Dy(img1->r)*img1->nchan;
+ while(p1 < p1e)
+ *p1++ = sqrt(*p1**p1 + *p2**p2++);
+
+ if(writememimage(1, img1) < 0)
+ sysfatal("writememimage: %r");+
+ freememimage(img2);
+ freememimage(img1);
+ exits(nil);
+}
--- /dev/null
+++ b/image/sub.c
@@ -1,0 +1,58 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <memdraw.h>
+
+static void
+usage(void)
+{+ fprint(2, "usage: %s img1 img2\n", argv0);
+ exits(nil);
+}
+
+void
+main(int argc, char *argv[])
+{+ Memimage *img1, *img2;
+ uchar *p1, *p2;
+ uchar *p1e;
+ int fd;
+
+ ARGBEGIN{+ default: usage();
+ }ARGEND;
+ if(argc != 2)
+ usage();
+
+ fd = open(argv[0], OREAD);
+ if(fd < 0)
+ sysfatal("open: %r");+ img1 = readmemimage(fd);
+ if(img1 == nil)
+ sysfatal("readmemimage: %r");+ close(fd);
+
+ fd = open(argv[1], OREAD);
+ if(fd < 0)
+ sysfatal("open: %r");+ img2 = readmemimage(fd);
+ if(img2 == nil)
+ sysfatal("readmemimage: %r");+ close(fd);
+
+ if(img1->chan != img2->chan || !eqrect(img1->r, img2->r))
+ sysfatal("images shapes differ");+
+ p1 = img1->data->bdata;
+ p2 = img2->data->bdata;
+ p1e = p1 + Dx(img1->r)*Dy(img1->r)*img1->nchan;
+ while(p1 < p1e)
+ *p1++ -= *p2++;
+
+ if(writememimage(1, img1) < 0)
+ sysfatal("writememimage: %r");+
+ freememimage(img2);
+ freememimage(img1);
+ exits(nil);
+}
--
⑨