int page_pgm(FILE *fout, potrace_path_t *plist, imginfo_t *imginfo) {
potrace_path_t *p;
greymap_t *gm;
render_t *rm;
int w, h;
trans_t t;
int mode;
char *comment = "created by "POTRACE" "VERSION", written by Peter Selinger 2001-2015";
t.bb[0] = imginfo->trans.bb[0]+imginfo->lmar+imginfo->rmar;
t.bb[1] = imginfo->trans.bb[1]+imginfo->tmar+imginfo->bmar;
t.orig[0] = imginfo->trans.orig[0]+imginfo->lmar;
t.orig[1] = imginfo->trans.orig[1]+imginfo->bmar;
t.x[0] = imginfo->trans.x[0];
t.x[1] = imginfo->trans.x[1];
t.y[0] = imginfo->trans.y[0];
t.y[1] = imginfo->trans.y[1];
w = (int)ceil(t.bb[0]);
h = (int)ceil(t.bb[1]);
gm = gm_new(w, h);
if (!gm) {
return 1;
}
rm = render_new(gm);
if (!rm) {
return 1;
}
gm_clear(gm, 255); /* white */
list_forall(p, plist) {
pgm_path(&p->curve, t, rm);
}
static void *interpolate_cubic(greymap_t *gm, int s, int bilevel, double c) {
int w, h;
double4 *poly = NULL; /* poly[s][4]: fixed interpolation polynomials */
double p[4]; /* four current points */
double4 *window = NULL; /* window[s][4]: current state */
double t, v;
int k, l, i, j, x, y;
double c1 = 0;
greymap_t *gm_out = NULL;
potrace_bitmap_t *bm_out = NULL;
SAFE_MALLOC(poly, s, double4);
SAFE_MALLOC(window, s, double4);
w = gm->w;
h = gm->h;
/* allocate output bitmap/greymap */
if (bilevel) {
bm_out = bm_new(w*s, h*s);
if (!bm_out) {
goto malloc_error;
}
bm_clear(bm_out, 0);
c1 = c * 255;
} else {
gm_out = gm_new(w*s, h*s);
if (!gm_out) {
goto malloc_error;
}
}
/* pre-calculate interpolation polynomials */
for (k=0; k<s; k++) {
t = k/(double)s;
poly[k][0] = 0.5 * t * (t-1) * (1-t);
poly[k][1] = -(t+1) * (t-1) * (1-t) + 0.5 * (t-1) * (t-2) * t;
poly[k][2] = 0.5 * (t+1) * t * (1-t) - t * (t-2) * t;
poly[k][3] = 0.5 * t * (t-1) * t;
}
/* interpolate */
for (y=0; y<h; y++) {
x=0;
for (i=0; i<4; i++) {
for (j=0; j<4; j++) {
p[j] = GM_BGET(gm, x+i-1, y+j-1);
}
for (k=0; k<s; k++) {
window[k][i] = 0.0;
for (j=0; j<4; j++) {
window[k][i] += poly[k][j] * p[j];
}
}
}
while (1) {
for (l=0; l<s; l++) {
for (k=0; k<s; k++) {
v = 0.0;
for (i=0; i<4; i++) {
v += window[k][i] * poly[l][i];
}
if (bilevel) {
BM_UPUT(bm_out, x*s+l, y*s+k, v < c1);
} else {
GM_UPUT(gm_out, x*s+l, y*s+k, v);
}
}
}
x++;
if (x>=w) {
break;
}
for (i=0; i<3; i++) {
for (k=0; k<s; k++) {
window[k][i] = window[k][i+1];
}
}
i=3;
for (j=0; j<4; j++) {
p[j] = GM_BGET(gm, x+i-1, y+j-1);
}
for (k=0; k<s; k++) {
window[k][i] = 0.0;
for (j=0; j<4; j++) {
window[k][i] += poly[k][j] * p[j];
}
}
}
}
free(poly);
free(window);
if (bilevel) {
return (void *)bm_out;
} else {
return (void *)gm_out;
}
malloc_error:
free(poly);
free(window);
return NULL;
}
static void *interpolate_linear(greymap_t *gm, int s, int bilevel, double c) {
int p00, p01, p10, p11;
int i, j, x, y;
double xx, yy, av;
double c1 = 0;
int w, h;
double p0, p1;
greymap_t *gm_out = NULL;
potrace_bitmap_t *bm_out = NULL;
w = gm->w;
h = gm->h;
/* allocate output bitmap/greymap */
if (bilevel) {
bm_out = bm_new(w*s, h*s);
if (!bm_out) {
return NULL;
}
bm_clear(bm_out, 0);
c1 = c * 255;
} else {
gm_out = gm_new(w*s, h*s);
if (!gm_out) {
return NULL;
}
}
/* interpolate */
for (i=0; i<w; i++) {
for (j=0; j<h; j++) {
p00 = GM_BGET(gm, i, j);
p01 = GM_BGET(gm, i, j+1);
p10 = GM_BGET(gm, i+1, j);
p11 = GM_BGET(gm, i+1, j+1);
if (bilevel) {
/* treat two special cases which are very common */
if (p00 < c1 && p01 < c1 && p10 < c1 && p11 < c1) {
for (x=0; x<s; x++) {
for (y=0; y<s; y++) {
BM_UPUT(bm_out, i*s+x, j*s+y, 1);
}
}
continue;
}
if (p00 >= c1 && p01 >= c1 && p10 >= c1 && p11 >= c1) {
continue;
}
}
/* the general case */
for (x=0; x<s; x++) {
xx = x/(double)s;
p0 = p00*(1-xx) + p10*xx;
p1 = p01*(1-xx) + p11*xx;
for (y=0; y<s; y++) {
yy = y/(double)s;
av = p0*(1-yy) + p1*yy;
if (bilevel) {
BM_UPUT(bm_out, i*s+x, j*s+y, av < c1);
} else {
GM_UPUT(gm_out, i*s+x, j*s+y, av);
}
}
}
}
}
if (bilevel) {
return (void *)bm_out;
} else {
return (void *)gm_out;
}
}
