+/*
+ * 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 <math.h>
#include <stdio.h>
#include <stdlib.h>
+#include <string.h>
#include <malloc.h>
#include "libqscale.h"
+/* The number of pixels to process at a time when scaling vertically. */
+#define CACHE_LINE_FACTOR 16
+
+/* Whether to use SSE for horizontal scaling or not (requires SSE3). */
+#define USE_HORIZONTAL_SSE 1
+
+/* Whether to use SSE for vertical scaling or not (requires only SSE1). */
+#define USE_VERTICAL_SSE 1
+
+#if USE_VERTICAL_SSE
+#undef CACHE_LINE_FACTOR
+#define CACHE_LINE_FACTOR 16
+#endif
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846264
+#endif
+
qscale_img *qscale_load_jpeg(const char *filename)
{
FILE *file = fopen(filename, "rb");
struct jpeg_error_mgr jerr;
dinfo.err = jpeg_std_error(&jerr);
jpeg_create_decompress(&dinfo);
- jpeg_stdio_src(&dinfo, stdin);
+ jpeg_stdio_src(&dinfo, file);
jpeg_read_header(&dinfo, TRUE);
dinfo.raw_data_out = TRUE;
jpeg_start_decompress(&dinfo);
img->w2 = dinfo.image_width * dinfo.comp_info[2].h_samp_factor / dinfo.max_h_samp_factor;
img->h2 = dinfo.image_height * dinfo.comp_info[2].v_samp_factor / dinfo.max_v_samp_factor;
+ img->samp_h0 = dinfo.comp_info[0].h_samp_factor;
+ img->samp_v0 = dinfo.comp_info[0].v_samp_factor;
+
+ img->samp_h1 = dinfo.comp_info[1].h_samp_factor;
+ img->samp_v1 = dinfo.comp_info[1].v_samp_factor;
+
+ img->samp_h2 = dinfo.comp_info[2].h_samp_factor;
+ img->samp_v2 = dinfo.comp_info[2].v_samp_factor;
+
img->data_y = (JSAMPLE*)memalign(16, dinfo.comp_info[0].height_in_blocks * dinfo.comp_info[0].width_in_blocks * DCTSIZE * DCTSIZE);
img->data_cb = (JSAMPLE*)memalign(16, dinfo.comp_info[1].height_in_blocks * dinfo.comp_info[1].width_in_blocks * DCTSIZE * DCTSIZE);
img->data_cr = (JSAMPLE*)memalign(16, dinfo.comp_info[2].height_in_blocks * dinfo.comp_info[2].width_in_blocks * DCTSIZE * DCTSIZE);
free(img->data_cr);
free(img);
}
+
+
+static double sinc(double x)
+{
+ static const double cutoff = 1.220703668e-4; /* sqrt(sqrt(eps)) */
+
+ if (abs(x) < cutoff) {
+ /* For small |x|, use Taylor series instead */
+ const double x2 = x * x;
+ const double x4 = x2 * x2;
+
+ return 1.0 - x2 / 6.0 + x4 / 120.0;
+ } else {
+ return sin(x) / x;
+ }
+}
+
+static double lanczos_tap(double x)
+{
+ 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);
+}
+
+static double mitchell_tap(double x)
+{
+ const double b = 1.0 / 3.0;
+ const double c = 1.0 / 3.0;
+ const double p0 = ( 6.0 - 2.0*b ) / 6.0;
+ const double p2 = (-18.0 + 12.0*b + 6.0*c) / 6.0;
+ const double p3 = ( 12.0 - 9.0*b - 6.0*c) / 6.0;
+ const double q0 = ( 8.0*b + 24.0*c) / 6.0;
+ const double q1 = ( - 12.0*b - 48.0*c) / 6.0;
+ const double q2 = ( 6.0*b + 30.0*c) / 6.0;
+ const double q3 = ( - b - 6.0*c) / 6.0;
+
+ if (x < -2.0) {
+ return 0.0;
+ } else if (x < -1.0) {
+ return q0 - x * (q1 - x * (q2 - x * q3));
+ } else if (x < 0.0) {
+ return p0 + x * x * (p2 - x * p3);
+ } else if (x < 1.0) {
+ return p0 + x * x * (p2 + x * p3);
+ } else if (x < 2.0) {
+ return q0 + x * (q1 + x * (q2 + x * q3));
+ } else {
+ return 0.0;
+ }
+}
+
+struct pix_desc {
+ unsigned start, end;
+ unsigned startcoeff;
+};
+
+static void hscale(float *pix, unsigned char *npix, unsigned w, unsigned h, unsigned nw, unsigned sstride, unsigned dstride, enum qscale_scaling_filter scaling_filter)
+{
+ 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;
+ double sf = (double)w / (double)nw;
+ double support;
+
+ if (scaling_filter == LANCZOS) {
+ support = (w > nw) ? (3.0 * sf) : (3.0 / sf);
+ } else { /* Mitchell */
+ support = (w > nw) ? (2.0 * sf) : (2.0 / sf);
+ }
+
+ /* calculate the filter */
+ for (x = 0; x < nw; ++x) {
+ int start = ceil(x * sf - support);
+ int end = floor(x * sf + support);
+ int sx;
+ double sum = 0.0;
+
+ if (start < 0) {
+ start = 0;
+ }
+ if (end > w - 1) {
+ end = w - 1;
+ }
+
+#if USE_HORIZONTAL_SSE
+ /* round up so we get a multiple of four for the SSE code */
+ int num = (end - start + 1);
+ if (num % 4 != 0) {
+ /* prefer aligning it if possible */
+ if (start % 4 != 0 && start % 4 <= num % 4) {
+ num += start % 4;
+ start -= start % 4;
+ }
+ if (num % 4 != 0) {
+ end += 4 - (num % 4);
+ }
+ }
+#endif
+
+ pd[x].start = start;
+ pd[x].end = end;
+ pd[x].startcoeff = num_coeffs;
+
+ for (sx = start; sx <= end; ++sx) {
+ double nd = (w > nw) ? (sx/sf - x) : (sx - x*sf);
+ double f;
+ if (scaling_filter == LANCZOS) {
+ f = lanczos_tap(nd);
+ } else { /* Mitchell */
+ f = mitchell_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) {
+ float *sptr = pix + y*sstride;
+ unsigned char *dptr = npix + y*dstride;
+ unsigned char ch;
+ for (x = 0; x < nw; ++x) {
+#if USE_HORIZONTAL_SSE
+ int result;
+ float acc;
+ long tmp;
+ static const float low = 0.0, high = 255.0;
+ __asm__ (
+ "pxor %1, %1 \n"
+ "xor %2, %2 \n"
+ "0: \n"
+ "movups (%4,%2),%%xmm1 \n"
+ "movups (%3,%2),%%xmm2 \n"
+ "mulps %%xmm2,%%xmm1 \n"
+ "addps %%xmm1,%1 \n"
+ "add $16,%2 \n"
+ "dec %5 \n"
+ "jnz 0b \n"
+ "haddps %1,%1 \n"
+ "haddps %1,%1 \n"
+ "maxss %6,%1 \n"
+ "minss %7,%1 \n"
+ "cvtss2si %1,%0 \n"
+ : "=r" (result),
+ "=&x" (acc),
+ "=&r" (tmp)
+ : "r" (&coeffs[pd[x].startcoeff]),
+ "r" (&sptr[pd[x].start]),
+ "r" ((pd[x].end - pd[x].start + 1)/4),
+ "m" (low),
+ "m" (high)
+ : "memory", "xmm1", "xmm2"
+ );
+
+ *dptr++ = (unsigned char)result;
+#else
+ 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++;
+ }
+
+ if (acc < 0.0)
+ ch = 0;
+ else if (acc > 255.0)
+ ch = 255;
+ else
+ ch = (unsigned char)acc;
+ *dptr++ = ch;
+#endif
+ }
+ ch = dptr[-1];
+ for ( ; x < dstride; ++x) {
+ *dptr++ = ch;
+ }
+ }
+}
+
+static void vscale(unsigned char *pix, float *npix, unsigned w, unsigned h, unsigned nh, unsigned dstride, enum qscale_scaling_filter scaling_filter)
+{
+ 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;
+
+ if (scaling_filter == LANCZOS) {
+ support = (h > nh) ? (3.0 * sf) : (3.0 / sf);
+ } else { /* Mitchell */
+ support = (h > nh) ? (2.0 * sf) : (2.0 / 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 = (h > nh) ? (sy/sf - y) : (sy - y*sf);
+ double f;
+ if (scaling_filter == LANCZOS) {
+ f = lanczos_tap(nd);
+ } else { /* Mitchell */
+ f = mitchell_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/CACHE_LINE_FACTOR) * CACHE_LINE_FACTOR; x += CACHE_LINE_FACTOR) {
+ unsigned char *sptr = pix + x;
+ float *dptr = npix + x;
+ for (y = 0; y < nh; ++y) {
+#if USE_VERTICAL_SSE
+ /*
+ * xmm0 - xmm3: acc[0..15]
+ * xmm4: current filter coefficient
+ * xmm5, xmm6, xmm7: scratchpad
+ */
+ __asm__ (
+ /* clear */
+ "pxor %%xmm0, %%xmm0 \n"
+ "pxor %%xmm1, %%xmm1 \n"
+ "pxor %%xmm2, %%xmm2 \n"
+ "pxor %%xmm3, %%xmm3 \n"
+
+ /* main loop */
+ "0: \n"
+
+ /* a zero is useful during unpacking */
+ "pxor %%xmm4, %%xmm4 \n"
+
+ /* fetch all 16 source bytes */
+ "movups (%0), %%xmm5 \n"
+ "prefetcht0 (%0,%3,4) \n"
+
+ /* unpack into words (xmm5, xmm7) */
+ "movaps %%xmm5, %%xmm7 \n"
+ "punpcklbw %%xmm4, %%xmm5 \n"
+ "punpckhbw %%xmm4, %%xmm7 \n"
+
+ /* unpack xmm5 into dwords (xmm5, xmm6) */
+ "movaps %%xmm5, %%xmm6 \n"
+ "punpcklwd %%xmm4, %%xmm5 \n"
+ "punpckhwd %%xmm4, %%xmm6 \n"
+
+ /* convert xmm5, xmm6 to floats */
+ "cvtdq2ps %%xmm5, %%xmm5 \n"
+ "cvtdq2ps %%xmm6, %%xmm6 \n"
+
+ /* fetch the coefficient */
+ "movss (%2), %%xmm4 \n"
+ "shufps $0x0, %%xmm4, %%xmm4 \n"
+
+ /* do the muls for xmm5 and xmm6 */
+ "mulps %%xmm4, %%xmm5 \n"
+ "mulps %%xmm4, %%xmm6 \n"
+ "addps %%xmm5, %%xmm0 \n"
+ "addps %%xmm6, %%xmm1 \n"
+
+ /* get the zero back again */
+ "pxor %%xmm4, %%xmm4 \n"
+
+ /* unpack xmm7 into dwords (xmm7, xmm6) */
+ "movaps %%xmm7, %%xmm6 \n"
+ "punpcklwd %%xmm4, %%xmm7 \n"
+ "punpckhwd %%xmm4, %%xmm6 \n"
+
+ /* convert xmm7, xmm6 to floats */
+ "cvtdq2ps %%xmm7, %%xmm7 \n"
+ "cvtdq2ps %%xmm6, %%xmm6 \n"
+
+ /* fetch the coefficient */
+ "movss (%2), %%xmm4 \n"
+ "shufps $0x0, %%xmm4, %%xmm4 \n"
+
+ /* do the second set of muls */
+ "mulps %%xmm4, %%xmm7 \n"
+ "mulps %%xmm4, %%xmm6 \n"
+ "addps %%xmm7, %%xmm2 \n"
+ "addps %%xmm6, %%xmm3 \n"
+
+ /* move along, and loop */
+ "add $4, %2 \n"
+ "add %3, %0 \n"
+ "dec %1 \n"
+ "jnz 0b \n"
+
+ /* store the values */
+ "movaps %%xmm0, (%4) \n"
+ "movaps %%xmm1, 16(%4) \n"
+ "movaps %%xmm2, 32(%4) \n"
+ "movaps %%xmm3, 48(%4) \n"
+ : :
+ "r" (&sptr[pd[y].start * w]), /* 0: srcptr base */
+ "r" (pd[y].end - pd[y].start + 1), /* 1: filter len */
+ "r" (&coeffs[pd[y].startcoeff]), /* 2: coeffs base */
+ "r" ((long)w), /* 3: stride */
+ "r" (dptr) /* 4: dstptr base */
+ : "memory", "xmm0", "xmm1", "xmm2", "xmm3", "xmm4", "xmm5", "xmm6", "xmm7"
+ );
+#else
+ 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;
+
+ 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) {
+ dptr[i] = acc[i];
+ }
+#endif
+ dptr += dstride;
+ }
+ }
+ for (x = (x/CACHE_LINE_FACTOR)*CACHE_LINE_FACTOR; x < w; ++x) {
+#else
+ for (x = 0; x < w; ++x) {
+#endif
+ unsigned char *sptr = pix + x;
+ float *dptr = npix + x;
+ for (y = 0; y < nh; ++y) {
+ float acc = 0.0;
+ float *cf = &coeffs[pd[y].startcoeff];
+ unsigned sy;
+
+ for (sy = pd[y].start; sy <= pd[y].end; ++sy) {
+ acc += sptr[sy * w] * *cf++;
+ }
+
+ *dptr = acc;
+ dptr += dstride;
+ }
+ }
+}
+
+qscale_img *qscale_clone(const qscale_img *img)
+{
+ qscale_img *dst = (qscale_img *)malloc(sizeof(qscale_img));
+ if (dst == NULL) {
+ return NULL;
+ }
+
+ *dst = *img;
+
+ unsigned dstride0 = (dst->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
+ unsigned dstride1 = (dst->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
+ unsigned dstride2 = (dst->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
+
+ /* FIXME: handle out-of-memory gracefully */
+ {
+ dst->data_y = (unsigned char *)malloc(dst->h0 * dstride0);
+ memcpy(dst->data_y, img->data_y, dst->h0 * dstride0);
+ }
+ {
+ dst->data_cb = (unsigned char *)malloc(dst->h1 * dstride1);
+ memcpy(dst->data_cb, img->data_cb, dst->h1 * dstride1);
+ }
+ {
+ dst->data_cr = (unsigned char *)malloc(dst->h2 * dstride2);
+ memcpy(dst->data_cr, img->data_cr, dst->h2 * dstride2);
+ }
+
+ return dst;
+}
+
+qscale_img *qscale_scale(qscale_img *src, unsigned width, unsigned height, unsigned samp_h0, unsigned samp_v0, unsigned samp_h1, unsigned samp_v1, unsigned samp_h2, unsigned samp_v2, enum qscale_scaling_filter scaling_filter)
+{
+ qscale_img *dst = (qscale_img *)malloc(sizeof(qscale_img));
+ if (dst == NULL) {
+ return NULL;
+ }
+
+ dst->width = width;
+ dst->height = height;
+
+ unsigned max_samp_h, max_samp_v;
+ max_samp_h = samp_h0;
+ if (samp_h1 > max_samp_h)
+ max_samp_h = samp_h1;
+ if (samp_h2 > max_samp_h)
+ max_samp_h = samp_h2;
+
+ max_samp_v = samp_v0;
+ if (samp_v1 > max_samp_v)
+ max_samp_v = samp_v1;
+ if (samp_v2 > max_samp_v)
+ max_samp_v = samp_v2;
+
+ dst->w0 = width * samp_h0 / max_samp_h;
+ dst->h0 = height * samp_v0 / max_samp_v;
+
+ dst->w1 = width * samp_h1 / max_samp_h;
+ dst->h1 = height * samp_v1 / max_samp_v;
+
+ dst->w2 = width * samp_h2 / max_samp_h;
+ dst->h2 = height * samp_v2 / max_samp_v;
+
+ dst->samp_h0 = samp_h0;
+ dst->samp_v0 = samp_v0;
+
+ dst->samp_h1 = samp_h1;
+ dst->samp_v1 = samp_v1;
+
+ dst->samp_h2 = samp_h2;
+ dst->samp_v2 = samp_v2;
+
+ unsigned dstride0 = (dst->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
+ unsigned dstride1 = (dst->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
+ unsigned dstride2 = (dst->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
+
+ unsigned sstride0 = (src->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
+ unsigned sstride1 = (src->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
+ unsigned sstride2 = (src->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
+
+ /* FIXME: handle out-of-memory gracefully */
+ {
+ float *npix = (float*)memalign(16, sstride0 * dst->h0 * sizeof(float));
+ vscale(src->data_y, npix, sstride0, src->h0, dst->h0, sstride0, scaling_filter);
+ dst->data_y = (unsigned char *)malloc(dst->h0 * dstride0);
+ hscale(npix, dst->data_y, src->w0, dst->h0, dst->w0, sstride0, dstride0, scaling_filter);
+ free(npix);
+ }
+ {
+ float *npix = (float*)memalign(16, sstride1 * dst->h1 * sizeof(float));
+ vscale(src->data_cr, npix, sstride1, src->h1, dst->h1, sstride1, scaling_filter);
+ dst->data_cr = (unsigned char *)malloc(dst->h1 * dstride1);
+ hscale(npix, dst->data_cr, src->w1, dst->h1, dst->w1, sstride1, dstride1, scaling_filter);
+ free(npix);
+ }
+ {
+ float *npix = (float*)memalign(16, sstride2 * dst->h2 * sizeof(float));
+ vscale(src->data_cb, npix, sstride2, src->h2, dst->h2, sstride2, scaling_filter);
+ dst->data_cb = (unsigned char *)malloc(dst->h2 * dstride2);
+ hscale(npix, dst->data_cb, src->w2, dst->h2, dst->w2, sstride2, dstride2, scaling_filter);
+ free(npix);
+ }
+
+ return dst;
+}
+
+int qscale_save_jpeg(const qscale_img *img, const char *filename, unsigned jpeg_quality, enum qscale_jpeg_mode jpeg_mode)
+{
+ FILE *file = fopen(filename, "wb");
+ if (file == NULL) {
+ return -1;
+ }
+
+ int err = qscale_save_jpeg_to_stdio(img, file, jpeg_quality, jpeg_mode);
+
+ fclose(file);
+ return err;
+}
+
+int qscale_save_jpeg_to_stdio(const qscale_img *img, FILE *file, unsigned jpeg_quality, enum qscale_jpeg_mode jpeg_mode)
+{
+ struct jpeg_compress_struct cinfo;
+ struct jpeg_error_mgr jerr;
+ cinfo.err = jpeg_std_error(&jerr);
+ jpeg_create_compress(&cinfo);
+ jpeg_stdio_dest(&cinfo, file);
+ cinfo.input_components = 3;
+ jpeg_set_defaults(&cinfo);
+ jpeg_set_quality(&cinfo, jpeg_quality, FALSE);
+
+ if (jpeg_mode == PROGRESSIVE) {
+ jpeg_simple_progression(&cinfo);
+ }
+
+ cinfo.image_width = img->width;
+ cinfo.image_height = img->height;
+ cinfo.raw_data_in = TRUE;
+ jpeg_set_colorspace(&cinfo, JCS_YCbCr);
+ cinfo.comp_info[0].h_samp_factor = img->samp_h0;
+ cinfo.comp_info[0].v_samp_factor = img->samp_v0;
+ cinfo.comp_info[1].h_samp_factor = img->samp_h1;
+ cinfo.comp_info[1].v_samp_factor = img->samp_v1;
+ cinfo.comp_info[2].h_samp_factor = img->samp_h2;
+ cinfo.comp_info[2].v_samp_factor = img->samp_v2;
+ jpeg_start_compress(&cinfo, TRUE);
+
+ unsigned dstride0 = (img->w0 + DCTSIZE-1) & ~(DCTSIZE-1);
+ unsigned dstride1 = (img->w1 + DCTSIZE-1) & ~(DCTSIZE-1);
+ unsigned dstride2 = (img->w2 + DCTSIZE-1) & ~(DCTSIZE-1);
+
+ int total_lines = 0;
+ int blocks = 0;
+ while (total_lines < cinfo.comp_info[0].height_in_blocks * DCTSIZE) {
+ unsigned max_lines = cinfo.max_v_samp_factor * DCTSIZE;
+
+ JSAMPROW y_row_ptrs[max_lines];
+ JSAMPROW cb_row_ptrs[max_lines];
+ JSAMPROW cr_row_ptrs[max_lines];
+ JSAMPROW* ptrs[] = { y_row_ptrs, cb_row_ptrs, cr_row_ptrs };
+ int i;
+
+ for (i = 0; i < max_lines; ++i) {
+ /* simple edge extension */
+ int yline = i + blocks*DCTSIZE*cinfo.comp_info[0].v_samp_factor;
+ if (yline > img->h0 - 1)
+ yline = img->h0 - 1;
+
+ int cbline = i + blocks*DCTSIZE*cinfo.comp_info[1].v_samp_factor;
+ if (cbline > img->h1 - 1)
+ cbline = img->h1 - 1;
+
+ int crline = i + blocks*DCTSIZE*cinfo.comp_info[2].v_samp_factor;
+ if (crline > img->h2 - 1)
+ crline = img->h2 - 1;
+
+ y_row_ptrs[i] = img->data_y + yline * dstride0;
+ cb_row_ptrs[i] = img->data_cb + cbline * dstride1;
+ cr_row_ptrs[i] = img->data_cr + crline * dstride2;
+ }
+
+ total_lines += max_lines;
+ ++blocks;
+
+ jpeg_write_raw_data(&cinfo, ptrs, max_lines);
+ }
+ jpeg_finish_compress(&cinfo);
+ jpeg_destroy_compress(&cinfo);
+
+ return 0;
+}
projects / qscale / blobdiff