X-Git-Url: https://git.pterodactylus.net/?a=blobdiff_plain;f=synfig-core%2Ftrunk%2Fsrc%2Fmodules%2Fmod_libavcodec%2Flibavcodec%2Fimgresample.c;fp=synfig-core%2Ftrunk%2Fsrc%2Fmodules%2Fmod_libavcodec%2Flibavcodec%2Fimgresample.c;h=140894d3654e4348133ac35ca539facfbb6ea8c0;hb=16b3beced25134bef064705568ecb893a6be4e79;hp=0000000000000000000000000000000000000000;hpb=5a1d028f56182922addfed8f1f1c28fdde12756c;p=synfig.git

diff --git a/synfig-core/trunk/src/modules/mod_libavcodec/libavcodec/imgresample.c b/synfig-core/trunk/src/modules/mod_libavcodec/libavcodec/imgresample.c
new file mode 100644
index 0000000..140894d
--- /dev/null
+++ b/synfig-core/trunk/src/modules/mod_libavcodec/libavcodec/imgresample.c
@@ -0,0 +1,775 @@
+/*
+ * High quality image resampling with polyphase filters 
+ * Copyright (c) 2001 Fabrice Bellard.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+ 
+/**
+ * @file imgresample.c
+ * High quality image resampling with polyphase filters .
+ */
+ 
+#include "avcodec.h"
+#include "dsputil.h"
+
+#ifdef USE_FASTMEMCPY
+#include "fastmemcpy.h"
+#endif
+
+#define NB_COMPONENTS 3
+
+#define PHASE_BITS 4
+#define NB_PHASES  (1 << PHASE_BITS)
+#define NB_TAPS    4
+#define FCENTER    1  /* index of the center of the filter */
+//#define TEST    1  /* Test it */
+
+#define POS_FRAC_BITS 16
+#define POS_FRAC      (1 << POS_FRAC_BITS)
+/* 6 bits precision is needed for MMX */
+#define FILTER_BITS   8
+
+#define LINE_BUF_HEIGHT (NB_TAPS * 4)
+
+struct ImgReSampleContext {
+    int iwidth, iheight, owidth, oheight, topBand, bottomBand, leftBand, rightBand;
+    int h_incr, v_incr;
+    int16_t h_filters[NB_PHASES][NB_TAPS] __align8; /* horizontal filters */
+    int16_t v_filters[NB_PHASES][NB_TAPS] __align8; /* vertical filters */
+    uint8_t *line_buf;
+};
+
+static inline int get_phase(int pos)
+{
+    return ((pos) >> (POS_FRAC_BITS - PHASE_BITS)) & ((1 << PHASE_BITS) - 1);
+}
+
+/* This function must be optimized */
+static void h_resample_fast(uint8_t *dst, int dst_width, uint8_t *src, int src_width,
+                            int src_start, int src_incr, int16_t *filters)
+{
+    int src_pos, phase, sum, i;
+    uint8_t *s;
+    int16_t *filter;
+
+    src_pos = src_start;
+    for(i=0;i<dst_width;i++) {
+#ifdef TEST
+        /* test */
+        if ((src_pos >> POS_FRAC_BITS) < 0 ||
+            (src_pos >> POS_FRAC_BITS) > (src_width - NB_TAPS))
+            av_abort();
+#endif
+        s = src + (src_pos >> POS_FRAC_BITS);
+        phase = get_phase(src_pos);
+        filter = filters + phase * NB_TAPS;
+#if NB_TAPS == 4
+        sum = s[0] * filter[0] +
+            s[1] * filter[1] +
+            s[2] * filter[2] +
+            s[3] * filter[3];
+#else
+        {
+            int j;
+            sum = 0;
+            for(j=0;j<NB_TAPS;j++)
+                sum += s[j] * filter[j];
+        }
+#endif
+        sum = sum >> FILTER_BITS;
+        if (sum < 0)
+            sum = 0;
+        else if (sum > 255)
+            sum = 255;
+        dst[0] = sum;
+        src_pos += src_incr;
+        dst++;
+    }
+}
+
+/* This function must be optimized */
+static void v_resample(uint8_t *dst, int dst_width, uint8_t *src, int wrap, 
+                       int16_t *filter)
+{
+    int sum, i;
+    uint8_t *s;
+
+    s = src;
+    for(i=0;i<dst_width;i++) {
+#if NB_TAPS == 4
+        sum = s[0 * wrap] * filter[0] +
+            s[1 * wrap] * filter[1] +
+            s[2 * wrap] * filter[2] +
+            s[3 * wrap] * filter[3];
+#else
+        {
+            int j;
+            uint8_t *s1 = s;
+
+            sum = 0;
+            for(j=0;j<NB_TAPS;j++) {
+                sum += s1[0] * filter[j];
+                s1 += wrap;
+            }
+        }
+#endif
+        sum = sum >> FILTER_BITS;
+        if (sum < 0)
+            sum = 0;
+        else if (sum > 255)
+            sum = 255;
+        dst[0] = sum;
+        dst++;
+        s++;
+    }
+}
+
+#ifdef HAVE_MMX
+
+#include "i386/mmx.h"
+
+#define FILTER4(reg) \
+{\
+        s = src + (src_pos >> POS_FRAC_BITS);\
+        phase = get_phase(src_pos);\
+        filter = filters + phase * NB_TAPS;\
+        movq_m2r(*s, reg);\
+        punpcklbw_r2r(mm7, reg);\
+        movq_m2r(*filter, mm6);\
+        pmaddwd_r2r(reg, mm6);\
+        movq_r2r(mm6, reg);\
+        psrlq_i2r(32, reg);\
+        paddd_r2r(mm6, reg);\
+        psrad_i2r(FILTER_BITS, reg);\
+        src_pos += src_incr;\
+}
+
+#define DUMP(reg) movq_r2m(reg, tmp); printf(#reg "=%016Lx\n", tmp.uq);
+
+/* XXX: do four pixels at a time */
+static void h_resample_fast4_mmx(uint8_t *dst, int dst_width, uint8_t *src, int src_width,
+                                 int src_start, int src_incr, int16_t *filters)
+{
+    int src_pos, phase;
+    uint8_t *s;
+    int16_t *filter;
+    mmx_t tmp;
+    
+    src_pos = src_start;
+    pxor_r2r(mm7, mm7);
+
+    while (dst_width >= 4) {
+
+        FILTER4(mm0);
+        FILTER4(mm1);
+        FILTER4(mm2);
+        FILTER4(mm3);
+
+        packuswb_r2r(mm7, mm0);
+        packuswb_r2r(mm7, mm1);
+        packuswb_r2r(mm7, mm3);
+        packuswb_r2r(mm7, mm2);
+        movq_r2m(mm0, tmp);
+        dst[0] = tmp.ub[0];
+        movq_r2m(mm1, tmp);
+        dst[1] = tmp.ub[0];
+        movq_r2m(mm2, tmp);
+        dst[2] = tmp.ub[0];
+        movq_r2m(mm3, tmp);
+        dst[3] = tmp.ub[0];
+        dst += 4;
+        dst_width -= 4;
+    }
+    while (dst_width > 0) {
+        FILTER4(mm0);
+        packuswb_r2r(mm7, mm0);
+        movq_r2m(mm0, tmp);
+        dst[0] = tmp.ub[0];
+        dst++;
+        dst_width--;
+    }
+    emms();
+}
+
+static void v_resample4_mmx(uint8_t *dst, int dst_width, uint8_t *src, int wrap, 
+                            int16_t *filter)
+{
+    int sum, i, v;
+    uint8_t *s;
+    mmx_t tmp;
+    mmx_t coefs[4];
+    
+    for(i=0;i<4;i++) {
+        v = filter[i];
+        coefs[i].uw[0] = v;
+        coefs[i].uw[1] = v;
+        coefs[i].uw[2] = v;
+        coefs[i].uw[3] = v;
+    }
+    
+    pxor_r2r(mm7, mm7);
+    s = src;
+    while (dst_width >= 4) {
+        movq_m2r(s[0 * wrap], mm0);
+        punpcklbw_r2r(mm7, mm0);
+        movq_m2r(s[1 * wrap], mm1);
+        punpcklbw_r2r(mm7, mm1);
+        movq_m2r(s[2 * wrap], mm2);
+        punpcklbw_r2r(mm7, mm2);
+        movq_m2r(s[3 * wrap], mm3);
+        punpcklbw_r2r(mm7, mm3);
+
+        pmullw_m2r(coefs[0], mm0);
+        pmullw_m2r(coefs[1], mm1);
+        pmullw_m2r(coefs[2], mm2);
+        pmullw_m2r(coefs[3], mm3);
+
+        paddw_r2r(mm1, mm0);
+        paddw_r2r(mm3, mm2);
+        paddw_r2r(mm2, mm0);
+        psraw_i2r(FILTER_BITS, mm0);
+        
+        packuswb_r2r(mm7, mm0);
+        movq_r2m(mm0, tmp);
+
+        *(uint32_t *)dst = tmp.ud[0];
+        dst += 4;
+        s += 4;
+        dst_width -= 4;
+    }
+    while (dst_width > 0) {
+        sum = s[0 * wrap] * filter[0] +
+            s[1 * wrap] * filter[1] +
+            s[2 * wrap] * filter[2] +
+            s[3 * wrap] * filter[3];
+        sum = sum >> FILTER_BITS;
+        if (sum < 0)
+            sum = 0;
+        else if (sum > 255)
+            sum = 255;
+        dst[0] = sum;
+        dst++;
+        s++;
+        dst_width--;
+    }
+    emms();
+}
+#endif
+
+#ifdef HAVE_ALTIVEC
+typedef	union {
+    vector unsigned char v;
+    unsigned char c[16];
+} vec_uc_t;
+
+typedef	union {
+    vector signed short v;
+    signed short s[8];
+} vec_ss_t;
+
+void v_resample16_altivec(uint8_t *dst, int dst_width, uint8_t *src, int wrap,
+                            int16_t *filter)
+{
+    int sum, i;
+    uint8_t *s;
+    vector unsigned char *tv, tmp, dstv, zero;
+    vec_ss_t srchv[4], srclv[4], fv[4];
+    vector signed short zeros, sumhv, sumlv;    
+    s = src;
+
+    for(i=0;i<4;i++)
+    {
+        /*
+           The vec_madds later on does an implicit >>15 on the result.
+           Since FILTER_BITS is 8, and we have 15 bits of magnitude in
+           a signed short, we have just enough bits to pre-shift our
+           filter constants <<7 to compensate for vec_madds.
+        */
+        fv[i].s[0] = filter[i] << (15-FILTER_BITS);
+        fv[i].v = vec_splat(fv[i].v, 0);
+    }
+    
+    zero = vec_splat_u8(0);
+    zeros = vec_splat_s16(0);
+
+
+    /*
+       When we're resampling, we'd ideally like both our input buffers,
+       and output buffers to be 16-byte aligned, so we can do both aligned
+       reads and writes. Sadly we can't always have this at the moment, so
+       we opt for aligned writes, as unaligned writes have a huge overhead.
+       To do this, do enough scalar resamples to get dst 16-byte aligned.
+    */
+    i = (-(int)dst) & 0xf;
+    while(i>0) {
+        sum = s[0 * wrap] * filter[0] +
+        s[1 * wrap] * filter[1] +
+        s[2 * wrap] * filter[2] +
+        s[3 * wrap] * filter[3];
+        sum = sum >> FILTER_BITS;
+        if (sum<0) sum = 0; else if (sum>255) sum=255;
+        dst[0] = sum;
+        dst++;
+        s++;
+        dst_width--;
+        i--;
+    }
+    
+    /* Do our altivec resampling on 16 pixels at once. */
+    while(dst_width>=16) {
+        /*
+           Read 16 (potentially unaligned) bytes from each of
+           4 lines into 4 vectors, and split them into shorts.
+           Interleave the multipy/accumulate for the resample
+           filter with the loads to hide the 3 cycle latency
+           the vec_madds have.
+        */
+        tv = (vector unsigned char *) &s[0 * wrap];
+        tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[i * wrap]));
+        srchv[0].v = (vector signed short) vec_mergeh(zero, tmp);
+        srclv[0].v = (vector signed short) vec_mergel(zero, tmp);
+        sumhv = vec_madds(srchv[0].v, fv[0].v, zeros);
+        sumlv = vec_madds(srclv[0].v, fv[0].v, zeros);
+
+        tv = (vector unsigned char *) &s[1 * wrap];
+        tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[1 * wrap]));
+        srchv[1].v = (vector signed short) vec_mergeh(zero, tmp);
+        srclv[1].v = (vector signed short) vec_mergel(zero, tmp);
+        sumhv = vec_madds(srchv[1].v, fv[1].v, sumhv);
+        sumlv = vec_madds(srclv[1].v, fv[1].v, sumlv);
+
+        tv = (vector unsigned char *) &s[2 * wrap];
+        tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[2 * wrap]));
+        srchv[2].v = (vector signed short) vec_mergeh(zero, tmp);
+        srclv[2].v = (vector signed short) vec_mergel(zero, tmp);
+        sumhv = vec_madds(srchv[2].v, fv[2].v, sumhv);
+        sumlv = vec_madds(srclv[2].v, fv[2].v, sumlv);
+
+        tv = (vector unsigned char *) &s[3 * wrap];
+        tmp = vec_perm(tv[0], tv[1], vec_lvsl(0, &s[3 * wrap]));
+        srchv[3].v = (vector signed short) vec_mergeh(zero, tmp);
+        srclv[3].v = (vector signed short) vec_mergel(zero, tmp);
+        sumhv = vec_madds(srchv[3].v, fv[3].v, sumhv);
+        sumlv = vec_madds(srclv[3].v, fv[3].v, sumlv);
+    
+        /*
+           Pack the results into our destination vector,
+           and do an aligned write of that back to memory.
+        */
+        dstv = vec_packsu(sumhv, sumlv) ;
+        vec_st(dstv, 0, (vector unsigned char *) dst);
+        
+        dst+=16;
+        s+=16;
+        dst_width-=16;
+    }
+
+    /*
+       If there are any leftover pixels, resample them
+       with the slow scalar method.
+    */
+    while(dst_width>0) {
+        sum = s[0 * wrap] * filter[0] +
+        s[1 * wrap] * filter[1] +
+        s[2 * wrap] * filter[2] +
+        s[3 * wrap] * filter[3];
+        sum = sum >> FILTER_BITS;
+        if (sum<0) sum = 0; else if (sum>255) sum=255;
+        dst[0] = sum;
+        dst++;
+        s++;
+        dst_width--;
+    }
+}
+#endif
+
+/* slow version to handle limit cases. Does not need optimisation */
+static void h_resample_slow(uint8_t *dst, int dst_width, uint8_t *src, int src_width,
+                            int src_start, int src_incr, int16_t *filters)
+{
+    int src_pos, phase, sum, j, v, i;
+    uint8_t *s, *src_end;
+    int16_t *filter;
+
+    src_end = src + src_width;
+    src_pos = src_start;
+    for(i=0;i<dst_width;i++) {
+        s = src + (src_pos >> POS_FRAC_BITS);
+        phase = get_phase(src_pos);
+        filter = filters + phase * NB_TAPS;
+        sum = 0;
+        for(j=0;j<NB_TAPS;j++) {
+            if (s < src)
+                v = src[0];
+            else if (s >= src_end)
+                v = src_end[-1];
+            else
+                v = s[0];
+            sum += v * filter[j];
+            s++;
+        }
+        sum = sum >> FILTER_BITS;
+        if (sum < 0)
+            sum = 0;
+        else if (sum > 255)
+            sum = 255;
+        dst[0] = sum;
+        src_pos += src_incr;
+        dst++;
+    }
+}
+
+static void h_resample(uint8_t *dst, int dst_width, uint8_t *src, int src_width,
+                       int src_start, int src_incr, int16_t *filters)
+{
+    int n, src_end;
+
+    if (src_start < 0) {
+        n = (0 - src_start + src_incr - 1) / src_incr;
+        h_resample_slow(dst, n, src, src_width, src_start, src_incr, filters);
+        dst += n;
+        dst_width -= n;
+        src_start += n * src_incr;
+    }
+    src_end = src_start + dst_width * src_incr;
+    if (src_end > ((src_width - NB_TAPS) << POS_FRAC_BITS)) {
+        n = (((src_width - NB_TAPS + 1) << POS_FRAC_BITS) - 1 - src_start) / 
+            src_incr;
+    } else {
+        n = dst_width;
+    }
+#ifdef HAVE_MMX
+    if ((mm_flags & MM_MMX) && NB_TAPS == 4)
+        h_resample_fast4_mmx(dst, n, 
+                             src, src_width, src_start, src_incr, filters);
+    else
+#endif
+        h_resample_fast(dst, n, 
+                        src, src_width, src_start, src_incr, filters);
+    if (n < dst_width) {
+        dst += n;
+        dst_width -= n;
+        src_start += n * src_incr;
+        h_resample_slow(dst, dst_width, 
+                        src, src_width, src_start, src_incr, filters);
+    }
+}
+
+static void component_resample(ImgReSampleContext *s, 
+                               uint8_t *output, int owrap, int owidth, int oheight,
+                               uint8_t *input, int iwrap, int iwidth, int iheight)
+{
+    int src_y, src_y1, last_src_y, ring_y, phase_y, y1, y;
+    uint8_t *new_line, *src_line;
+
+    last_src_y = - FCENTER - 1;
+    /* position of the bottom of the filter in the source image */
+    src_y = (last_src_y + NB_TAPS) * POS_FRAC; 
+    ring_y = NB_TAPS; /* position in ring buffer */
+    for(y=0;y<oheight;y++) {
+        /* apply horizontal filter on new lines from input if needed */
+        src_y1 = src_y >> POS_FRAC_BITS;
+        while (last_src_y < src_y1) {
+            if (++ring_y >= LINE_BUF_HEIGHT + NB_TAPS)
+                ring_y = NB_TAPS;
+            last_src_y++;
+            /* handle limit conditions : replicate line (slightly
+               inefficient because we filter multiple times) */
+            y1 = last_src_y;
+            if (y1 < 0) {
+                y1 = 0;
+            } else if (y1 >= iheight) {
+                y1 = iheight - 1;
+            }
+            src_line = input + y1 * iwrap;
+            new_line = s->line_buf + ring_y * owidth;
+            /* apply filter and handle limit cases correctly */
+            h_resample(new_line, owidth, 
+                       src_line, iwidth, - FCENTER * POS_FRAC, s->h_incr, 
+                       &s->h_filters[0][0]);
+            /* handle ring buffer wraping */
+            if (ring_y >= LINE_BUF_HEIGHT) {
+                memcpy(s->line_buf + (ring_y - LINE_BUF_HEIGHT) * owidth,
+                       new_line, owidth);
+            }
+        }
+        /* apply vertical filter */
+        phase_y = get_phase(src_y);
+#ifdef HAVE_MMX
+        /* desactivated MMX because loss of precision */
+        if ((mm_flags & MM_MMX) && NB_TAPS == 4 && 0)
+            v_resample4_mmx(output, owidth, 
+                            s->line_buf + (ring_y - NB_TAPS + 1) * owidth, owidth, 
+                            &s->v_filters[phase_y][0]);
+        else
+#endif
+#ifdef HAVE_ALTIVEC
+            if ((mm_flags & MM_ALTIVEC) && NB_TAPS == 4 && FILTER_BITS <= 6)
+                v_resample16_altivec(output, owidth,
+                                s->line_buf + (ring_y - NB_TAPS + 1) * owidth, owidth,
+                                &s->v_filters[phase_y][0]);
+        else
+#endif
+            v_resample(output, owidth, 
+                       s->line_buf + (ring_y - NB_TAPS + 1) * owidth, owidth, 
+                       &s->v_filters[phase_y][0]);
+            
+        src_y += s->v_incr;
+        output += owrap;
+    }
+}
+
+/* XXX: the following filter is quite naive, but it seems to suffice
+   for 4 taps */
+static void build_filter(int16_t *filter, float factor)
+{
+    int ph, i, v;
+    float x, y, tab[NB_TAPS], norm, mult;
+
+    /* if upsampling, only need to interpolate, no filter */
+    if (factor > 1.0)
+        factor = 1.0;
+
+    for(ph=0;ph<NB_PHASES;ph++) {
+        norm = 0;
+        for(i=0;i<NB_TAPS;i++) {
+            
+            x = M_PI * ((float)(i - FCENTER) - (float)ph / NB_PHASES) * factor;
+            if (x == 0)
+                y = 1.0;
+            else
+                y = sin(x) / x;
+            tab[i] = y;
+            norm += y;
+        }
+
+        /* normalize so that an uniform color remains the same */
+        mult = (float)(1 << FILTER_BITS) / norm;
+        for(i=0;i<NB_TAPS;i++) {
+            v = (int)(tab[i] * mult);
+            filter[ph * NB_TAPS + i] = v;
+        }
+    }
+}
+
+ImgReSampleContext *img_resample_init(int owidth, int oheight,
+                                      int iwidth, int iheight)
+{
+	return img_resample_full_init(owidth, oheight, iwidth, iheight, 0, 0, 0, 0);
+}
+
+ImgReSampleContext *img_resample_full_init(int owidth, int oheight,
+                                      int iwidth, int iheight,
+                                      int topBand, int bottomBand,
+                                      int leftBand, int rightBand)
+{
+    ImgReSampleContext *s;
+
+    s = av_mallocz(sizeof(ImgReSampleContext));
+    if (!s)
+        return NULL;
+    s->line_buf = av_mallocz(owidth * (LINE_BUF_HEIGHT + NB_TAPS));
+    if (!s->line_buf) 
+        goto fail;
+    
+    s->owidth = owidth;
+    s->oheight = oheight;
+    s->iwidth = iwidth;
+    s->iheight = iheight;
+    s->topBand = topBand;
+    s->bottomBand = bottomBand;
+    s->leftBand = leftBand;
+    s->rightBand = rightBand;
+    
+    s->h_incr = ((iwidth - leftBand - rightBand) * POS_FRAC) / owidth;
+    s->v_incr = ((iheight - topBand - bottomBand) * POS_FRAC) / oheight;
+    
+    build_filter(&s->h_filters[0][0], (float) owidth  / (float) (iwidth - leftBand - rightBand));
+    build_filter(&s->v_filters[0][0], (float) oheight / (float) (iheight - topBand - bottomBand));
+
+    return s;
+ fail:
+    av_free(s);
+    return NULL;
+}
+
+void img_resample(ImgReSampleContext *s, 
+                  AVPicture *output, AVPicture *input)
+{
+    int i, shift;
+
+    for(i=0;i<3;i++) {
+        shift = (i == 0) ? 0 : 1;
+        component_resample(s, output->data[i], output->linesize[i], 
+                           s->owidth >> shift, s->oheight >> shift,
+                           input->data[i] + (input->linesize[i] * (s->topBand >> shift)) + (s->leftBand >> shift),
+                           input->linesize[i], ((s->iwidth - s->leftBand - s->rightBand) >> shift),
+                           (s->iheight - s->topBand - s->bottomBand) >> shift);
+    }
+}
+
+void img_resample_close(ImgReSampleContext *s)
+{
+    av_free(s->line_buf);
+    av_free(s);
+}
+
+#ifdef TEST
+
+void *av_mallocz(int size)
+{
+    void *ptr;
+    ptr = malloc(size);
+    memset(ptr, 0, size);
+    return ptr;
+}
+
+void av_free(void *ptr)
+{
+    /* XXX: this test should not be needed on most libcs */
+    if (ptr)
+        free(ptr);
+}
+
+/* input */
+#define XSIZE 256
+#define YSIZE 256
+uint8_t img[XSIZE * YSIZE];
+
+/* output */
+#define XSIZE1 512
+#define YSIZE1 512
+uint8_t img1[XSIZE1 * YSIZE1];
+uint8_t img2[XSIZE1 * YSIZE1];
+
+void save_pgm(const char *filename, uint8_t *img, int xsize, int ysize)
+{
+    FILE *f;
+    f=fopen(filename,"w");
+    fprintf(f,"P5\n%d %d\n%d\n", xsize, ysize, 255);
+    fwrite(img,1, xsize * ysize,f);
+    fclose(f);
+}
+
+static void dump_filter(int16_t *filter)
+{
+    int i, ph;
+
+    for(ph=0;ph<NB_PHASES;ph++) {
+        printf("%2d: ", ph);
+        for(i=0;i<NB_TAPS;i++) {
+            printf(" %5.2f", filter[ph * NB_TAPS + i] / 256.0);
+        }
+        printf("\n");
+    }
+}
+
+#ifdef HAVE_MMX
+int mm_flags;
+#endif
+
+int main(int argc, char **argv)
+{
+    int x, y, v, i, xsize, ysize;
+    ImgReSampleContext *s;
+    float fact, factors[] = { 1/2.0, 3.0/4.0, 1.0, 4.0/3.0, 16.0/9.0, 2.0 };
+    char buf[256];
+
+    /* build test image */
+    for(y=0;y<YSIZE;y++) {
+        for(x=0;x<XSIZE;x++) {
+            if (x < XSIZE/2 && y < YSIZE/2) {
+                if (x < XSIZE/4 && y < YSIZE/4) {
+                    if ((x % 10) <= 6 &&
+                        (y % 10) <= 6)
+                        v = 0xff;
+                    else
+                        v = 0x00;
+                } else if (x < XSIZE/4) {
+                    if (x & 1) 
+                        v = 0xff;
+                    else 
+                        v = 0;
+                } else if (y < XSIZE/4) {
+                    if (y & 1) 
+                        v = 0xff;
+                    else 
+                        v = 0;
+                } else {
+                    if (y < YSIZE*3/8) {
+                        if ((y+x) & 1) 
+                            v = 0xff;
+                        else 
+                            v = 0;
+                    } else {
+                        if (((x+3) % 4) <= 1 &&
+                            ((y+3) % 4) <= 1)
+                            v = 0xff;
+                        else
+                            v = 0x00;
+                    }
+                }
+            } else if (x < XSIZE/2) {
+                v = ((x - (XSIZE/2)) * 255) / (XSIZE/2);
+            } else if (y < XSIZE/2) {
+                v = ((y - (XSIZE/2)) * 255) / (XSIZE/2);
+            } else {
+                v = ((x + y - XSIZE) * 255) / XSIZE;
+            }
+            img[(YSIZE - y) * XSIZE + (XSIZE - x)] = v;
+        }
+    }
+    save_pgm("/tmp/in.pgm", img, XSIZE, YSIZE);
+    for(i=0;i<sizeof(factors)/sizeof(float);i++) {
+        fact = factors[i];
+        xsize = (int)(XSIZE * fact);
+        ysize = (int)((YSIZE - 100) * fact);
+        s = img_resample_full_init(xsize, ysize, XSIZE, YSIZE, 50 ,50, 0, 0);
+        printf("Factor=%0.2f\n", fact);
+        dump_filter(&s->h_filters[0][0]);
+        component_resample(s, img1, xsize, xsize, ysize,
+                           img + 50 * XSIZE, XSIZE, XSIZE, YSIZE - 100);
+        img_resample_close(s);
+
+        sprintf(buf, "/tmp/out%d.pgm", i);
+        save_pgm(buf, img1, xsize, ysize);
+    }
+
+    /* mmx test */
+#ifdef HAVE_MMX
+    printf("MMX test\n");
+    fact = 0.72;
+    xsize = (int)(XSIZE * fact);
+    ysize = (int)(YSIZE * fact);
+    mm_flags = MM_MMX;
+    s = img_resample_init(xsize, ysize, XSIZE, YSIZE);
+    component_resample(s, img1, xsize, xsize, ysize,
+                       img, XSIZE, XSIZE, YSIZE);
+
+    mm_flags = 0;
+    s = img_resample_init(xsize, ysize, XSIZE, YSIZE);
+    component_resample(s, img2, xsize, xsize, ysize,
+                       img, XSIZE, XSIZE, YSIZE);
+    if (memcmp(img1, img2, xsize * ysize) != 0) {
+        fprintf(stderr, "mmx error\n");
+        exit(1);
+    }
+    printf("MMX OK\n");
+#endif
+    return 0;
+}
+
+#endif