X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=qscale.c;h=6da1b390ab5ca46616c1dea74a10d96082a4c455;hb=89b54dc15de5f3c27ce8bed9f1490b9b4ba16b35;hp=61f49c42df3487ea893beea8a99238eab94d8fdf;hpb=44d2d19e679c578800f420739385a159b8246949;p=qscale diff --git a/qscale.c b/qscale.c index 61f49c4..6da1b39 100644 --- a/qscale.c +++ b/qscale.c @@ -1,281 +1,41 @@ +/* + * qscale: Quick, high-quality JPEG-to-JPEG scaler. + * Copyright (C) 2008 Steinar H. Gunderson + * + * 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 -#include -#include #include +#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; } +