+/*
+ * qscale: Quick, high-quality JPEG-to-JPEG scaler.
+ * Copyright (C) 2008 Steinar H. Gunderson <sgunderson@bigfoot.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
#include <stdio.h>
-#include <math.h>
-#include <string.h>
#include <stdlib.h>
+#include "libqscale.h"
-#define CACHE_LINE_FACTOR 1
-
-void myreadline(char *buf)
-{
- char *ptr;
-
- if (fgets(buf, 256, stdin) == NULL) {
- fprintf(stderr, "Premuture EOF\n");
- exit(1);
- }
-
- if (strlen(buf) == 0) {
- return;
- }
-
- ptr = &buf[strlen(buf) - 1];
- if (*ptr == '\n') {
- *ptr-- = 0;
- if (*ptr == '\r') {
- *ptr = 0;
- }
- }
-}
-
-double sinc(double x)
-{
- // This is bad for very small x, should use power series instead.
- if (x == 0.0)
- return 1.0;
- else
- return sin(x) / x;
-}
-
-double lanczos_tap(double x)
+int main(int argc, char **argv)
{
- if (x < -3.0 || x > 3.0)
- return 0.0;
- if (x < 0.0)
- return sinc(-x*M_PI) * sinc(-x*M_PI / 3.0);
- else
- return sinc(x*M_PI) * sinc(x*M_PI / 3.0);
-}
-
-
-struct pix_desc {
- unsigned start, end;
- unsigned startcoeff;
-};
-
-void hscale(unsigned char *pix, float *npix, unsigned w, unsigned h, unsigned nw)
-{
- struct pix_desc *pd = (struct pix_desc *)malloc(nw * sizeof(struct pix_desc));
- int size_coeffs = 8;
- float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
- int num_coeffs = 0;
- int x, y, sx;
- double sf = (double)w / (double)nw;
- double support = 3.0 * sf;
-
- /* calculate the filter */
- for (x = 0; x < nw; ++x) {
- int start = ceil(x * sf - support);
- int end = floor(x * sf + support);
- double sum = 0.0;
-
- if (start < 0) {
- start = 0;
- }
- if (end > w - 1) {
- end = w - 1;
- }
-
- pd[x].start = start;
- pd[x].end = end;
- pd[x].startcoeff = num_coeffs;
-
- for (sx = start; sx <= end; ++sx) {
- double nd = sx/sf - x;
- double f = lanczos_tap(nd);
- if (num_coeffs == size_coeffs) {
- size_coeffs <<= 1;
- coeffs = (float *)realloc(coeffs, size_coeffs * sizeof(float));
- }
-
- coeffs[num_coeffs++] = f;
- sum += f;
- }
-
- for (sx = start; sx <= end; ++sx) {
- coeffs[pd[x].startcoeff + sx - start] /= sum;
- }
- }
-
- for (y = 0; y < h; ++y) {
- unsigned char *sptr = pix + y*w;
- float *dptr = npix + y*nw;
- for (x = 0; x < nw; ++x) {
- float acc = 0.0;
- float *cf = &coeffs[pd[x].startcoeff];
- unsigned sx;
-
- for (sx = pd[x].start; sx <= pd[x].end; ++sx) {
- acc += sptr[sx] * *cf++;
- }
- *dptr++ = acc;
- }
- }
-}
-
-void vscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nh)
-{
- struct pix_desc *pd = (struct pix_desc *)malloc(nh * sizeof(struct pix_desc));
- int size_coeffs = 8;
- float *coeffs = (float *)malloc(size_coeffs * sizeof(float));
- int num_coeffs = 0;
- int x, y, sy;
- double sf = (double)h / (double)nh;
- double support = 3.0 * sf;
-
- /* calculate the filter */
- for (y = 0; y < nh; ++y) {
- int start = ceil(y * sf - support);
- int end = floor(y * sf + support);
- double sum = 0.0;
-
- if (start < 0) {
- start = 0;
- }
- if (end > h - 1) {
- end = h - 1;
- }
-
- pd[y].start = start;
- pd[y].end = end;
- pd[y].startcoeff = num_coeffs;
-
- for (sy = start; sy <= end; ++sy) {
- double nd = sy/sf - y;
- double f = lanczos_tap(nd);
- if (num_coeffs == size_coeffs) {
- size_coeffs <<= 1;
- coeffs = (float *)realloc(coeffs, size_coeffs * sizeof(float));
- }
-
- coeffs[num_coeffs++] = f;
- sum += f;
- }
-
- for (sy = start; sy <= end; ++sy) {
- coeffs[pd[y].startcoeff + sy - start] /= sum;
- }
- }
-#if CACHE_LINE_FACTOR > 1
- for (x = 0; x < w; x += CACHE_LINE_FACTOR) {
- float *sptr = pix + x;
- unsigned char *dptr = npix + x;
- for (y = 0; y < nh; ++y) {
- int i;
- float acc[CACHE_LINE_FACTOR];
- for (i = 0; i < CACHE_LINE_FACTOR; ++i)
- acc[i] = 0.0;
- float *cf = &coeffs[pd[y].startcoeff];
- unsigned sy;
- unsigned char ch;
-
- for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
- for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
- acc[i] += sptr[sy * w + i] * *cf;
- }
- ++cf;
- }
-
- for (i = 0; i < CACHE_LINE_FACTOR; ++i) {
- if (acc[i] < 0.0)
- ch = 0;
- else if (acc[i] > 255.0)
- ch = 255;
- else
- ch = (unsigned char)acc[i];
- dptr[i] = ch;
- }
- dptr += w;
- }
- }
-#endif
- for (x = (x/CACHE_LINE_FACTOR)*CACHE_LINE_FACTOR; x < w; ++x) {
- float *sptr = pix + x;
- unsigned char *dptr = npix + x;
- for (y = 0; y < nh; ++y) {
- float acc = 0.0;
- float *cf = &coeffs[pd[y].startcoeff];
- unsigned sy;
- unsigned char ch;
-
- for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
- acc += sptr[sy * w] * *cf++;
- }
-
- if (acc < 0.0)
- ch = 0;
- else if (acc > 255.0)
- ch = 255;
- else
- ch = (unsigned char)acc;
-
- *dptr = ch;
- dptr += w;
- }
- }
-}
-
-int main(void)
-{
- unsigned w, h;
- unsigned nw = 600, nh = 400;
- char buf[256];
- unsigned char *pix;
- float *npix;
- unsigned char *npix2;
-
- myreadline(buf);
- if (strcmp(buf, "P5") != 0) {
- fprintf(stderr, "Error: Not a PGM file\n");
- exit(1);
- }
- myreadline(buf); /* comment */
- myreadline(buf);
-
- if (sscanf(buf, "%u %u", &w, &h) != 2) {
- fprintf(stderr, "Error: Expected width/height\n");
- exit(1);
- }
-
- myreadline(buf);
- if (strcmp(buf, "255") != 0) {
- fprintf(stderr, "Error: Expected 8-bit\n");
- exit(1);
- }
-
- pix = (unsigned char *)malloc(w * h);
- if (pix == NULL) {
- perror("malloc");
- exit(1);
- }
-
- if (fread(pix, w*h, 1, stdin) != 1) {
- fprintf(stderr, "Error: Short read\n");
- exit(1);
- }
-
- npix = (float *)malloc(sizeof(float) * nw * h);
- if (npix == NULL) {
- perror("malloc");
- exit(1);
- }
- npix2 = (unsigned char *)malloc(nw * nh);
- if (npix2 == NULL) {
- perror("malloc");
- exit(1);
- }
-
- hscale(pix, npix, w, h, nw);
- vscale(npix, npix2, nw, h, nh);
-
- printf("P5\n# COMMENT: Made by qscale\n%u %u\n255\n", nw, nh);
- {
- int y, x;
- for (y = 0; y < nh; ++y) {
- for (x = 0; x < nw; ++x) {
- putchar(npix2[y * nw + x]);
- }
- }
- }
+ /* user-settable parameters */
+ unsigned nominal_w = atoi(argv[1]);
+ unsigned nominal_h = atoi(argv[2]);
+ unsigned samp_h0 = 2, samp_v0 = 2;
+ unsigned samp_h1 = 1, samp_v1 = 1;
+ unsigned samp_h2 = 1, samp_v2 = 1;
+ unsigned jpeg_quality = 85;
+ /* end */
+
+ qscale_img *img = qscale_load_jpeg_from_stdio(stdin);
+ qscale_img *scaled = qscale_scale(img, nominal_w, nominal_h, samp_h0, samp_v0, samp_h1, samp_v1, samp_h2, samp_v2, LANCZOS);
+ qscale_destroy(img);
+ qscale_save_jpeg_to_stdio(scaled, stdout, jpeg_quality, SEQUENTIAL);
return 0;
}
+
projects / qscale / blobdiff