/*

  * Copyright 2011 Stefano Sabatini <stefano.sabatini-lala poste it>
  * Copyright 2012 Nicolas George <nicolas.george normalesup org>
  *

  * This file is part of FFmpeg.
  *
  * FFmpeg 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 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 

 #include <string.h>
 

 #include "libavutil/avassert.h"

 #include "libavutil/avutil.h"
 #include "libavutil/colorspace.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/mem.h"

 #include "libavutil/pixdesc.h"
 #include "drawutils.h"

 #include "formats.h"

 
 enum { RED = 0, GREEN, BLUE, ALPHA };
 

 int ff_fill_rgba_map(uint8_t *rgba_map, enum AVPixelFormat pix_fmt)

 {
     switch (pix_fmt) {

     case AV_PIX_FMT_0RGB:

     case AV_PIX_FMT_ARGB:  rgba_map[ALPHA] = 0; rgba_map[RED  ] = 1; rgba_map[GREEN] = 2; rgba_map[BLUE ] = 3; break;

     case AV_PIX_FMT_0BGR:

     case AV_PIX_FMT_ABGR:  rgba_map[ALPHA] = 0; rgba_map[BLUE ] = 1; rgba_map[GREEN] = 2; rgba_map[RED  ] = 3; break;

     case AV_PIX_FMT_RGB48LE:
     case AV_PIX_FMT_RGB48BE:
     case AV_PIX_FMT_RGBA64BE:
     case AV_PIX_FMT_RGBA64LE:

     case AV_PIX_FMT_RGB0:

     case AV_PIX_FMT_RGBA:
     case AV_PIX_FMT_RGB24: rgba_map[RED  ] = 0; rgba_map[GREEN] = 1; rgba_map[BLUE ] = 2; rgba_map[ALPHA] = 3; break;

     case AV_PIX_FMT_BGR48LE:
     case AV_PIX_FMT_BGR48BE:
     case AV_PIX_FMT_BGRA64BE:
     case AV_PIX_FMT_BGRA64LE:

     case AV_PIX_FMT_BGRA:

     case AV_PIX_FMT_BGR0:

     case AV_PIX_FMT_BGR24: rgba_map[BLUE ] = 0; rgba_map[GREEN] = 1; rgba_map[RED  ] = 2; rgba_map[ALPHA] = 3; break;

     case AV_PIX_FMT_GBRP9LE:

     case AV_PIX_FMT_GBRP9BE:

     case AV_PIX_FMT_GBRP10LE:

     case AV_PIX_FMT_GBRP10BE:

     case AV_PIX_FMT_GBRP12LE:

     case AV_PIX_FMT_GBRP12BE:

     case AV_PIX_FMT_GBRP14LE:

     case AV_PIX_FMT_GBRP14BE:
     case AV_PIX_FMT_GBRP16LE:
     case AV_PIX_FMT_GBRP16BE:

     case AV_PIX_FMT_GBRAP:

     case AV_PIX_FMT_GBRAP10LE:
     case AV_PIX_FMT_GBRAP10BE:

     case AV_PIX_FMT_GBRAP12LE:
     case AV_PIX_FMT_GBRAP12BE:
     case AV_PIX_FMT_GBRAP16LE:
     case AV_PIX_FMT_GBRAP16BE:

     case AV_PIX_FMT_GBRP:  rgba_map[GREEN] = 0; rgba_map[BLUE ] = 1; rgba_map[RED  ] = 2; rgba_map[ALPHA] = 3; break;

     default:                    /* unsupported */
         return AVERROR(EINVAL);

     }

     return 0;
 }
 
 int ff_fill_line_with_color(uint8_t *line[4], int pixel_step[4], int w, uint8_t dst_color[4],

                             enum AVPixelFormat pix_fmt, uint8_t rgba_color[4],

                             int *is_packed_rgba, uint8_t rgba_map_ptr[4])
 {
     uint8_t rgba_map[4] = {0};
     int i;

     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(pix_fmt);

     int hsub;
 
     av_assert0(pix_desc);
 
     hsub = pix_desc->log2_chroma_w;

 
     *is_packed_rgba = ff_fill_rgba_map(rgba_map, pix_fmt) >= 0;

 
     if (*is_packed_rgba) {
         pixel_step[0] = (av_get_bits_per_pixel(pix_desc))>>3;
         for (i = 0; i < 4; i++)
             dst_color[rgba_map[i]] = rgba_color[i];
 

         line[0] = av_malloc_array(w, pixel_step[0]);

         if (!line[0])
             return AVERROR(ENOMEM);

         for (i = 0; i < w; i++)
             memcpy(line[0] + i * pixel_step[0], dst_color, pixel_step[0]);
         if (rgba_map_ptr)
             memcpy(rgba_map_ptr, rgba_map, sizeof(rgba_map[0]) * 4);
     } else {
         int plane;
 
         dst_color[0] = RGB_TO_Y_CCIR(rgba_color[0], rgba_color[1], rgba_color[2]);
         dst_color[1] = RGB_TO_U_CCIR(rgba_color[0], rgba_color[1], rgba_color[2], 0);
         dst_color[2] = RGB_TO_V_CCIR(rgba_color[0], rgba_color[1], rgba_color[2], 0);
         dst_color[3] = rgba_color[3];
 
         for (plane = 0; plane < 4; plane++) {
             int line_size;
             int hsub1 = (plane == 1 || plane == 2) ? hsub : 0;
 
             pixel_step[plane] = 1;

             line_size = AV_CEIL_RSHIFT(w, hsub1) * pixel_step[plane];

             line[plane] = av_malloc(line_size);

             if (!line[plane]) {
                 while(plane && line[plane-1])
                     av_freep(&line[--plane]);
                 return AVERROR(ENOMEM);
             }

             memset(line[plane], dst_color[plane], line_size);
         }
     }
 
     return 0;
 }
 
 void ff_draw_rectangle(uint8_t *dst[4], int dst_linesize[4],
                        uint8_t *src[4], int pixelstep[4],
                        int hsub, int vsub, int x, int y, int w, int h)
 {
     int i, plane;
     uint8_t *p;
 
     for (plane = 0; plane < 4 && dst[plane]; plane++) {
         int hsub1 = plane == 1 || plane == 2 ? hsub : 0;
         int vsub1 = plane == 1 || plane == 2 ? vsub : 0;

         int width  = AV_CEIL_RSHIFT(w, hsub1);
         int height = AV_CEIL_RSHIFT(h, vsub1);

 
         p = dst[plane] + (y >> vsub1) * dst_linesize[plane];

         for (i = 0; i < height; i++) {

             memcpy(p + (x >> hsub1) * pixelstep[plane],

                    src[plane], width * pixelstep[plane]);

             p += dst_linesize[plane];
         }
     }
 }
 
 void ff_copy_rectangle(uint8_t *dst[4], int dst_linesize[4],
                        uint8_t *src[4], int src_linesize[4], int pixelstep[4],
                        int hsub, int vsub, int x, int y, int y2, int w, int h)
 {
     int i, plane;
     uint8_t *p;
 
     for (plane = 0; plane < 4 && dst[plane]; plane++) {
         int hsub1 = plane == 1 || plane == 2 ? hsub : 0;
         int vsub1 = plane == 1 || plane == 2 ? vsub : 0;

         int width  = AV_CEIL_RSHIFT(w, hsub1);
         int height = AV_CEIL_RSHIFT(h, vsub1);

 
         p = dst[plane] + (y >> vsub1) * dst_linesize[plane];

         for (i = 0; i < height; i++) {

             memcpy(p + (x >> hsub1) * pixelstep[plane],

                    src[plane] + src_linesize[plane]*(i+(y2>>vsub1)), width * pixelstep[plane]);

             p += dst_linesize[plane];
         }
     }
 }

 int ff_draw_init(FFDrawContext *draw, enum AVPixelFormat format, unsigned flags)

 {

     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(format);

     const AVComponentDescriptor *c;
     unsigned i, nb_planes = 0;
     int pixelstep[MAX_PLANES] = { 0 };
 

     if (!desc || !desc->name)

         return AVERROR(EINVAL);

     if (desc->flags & ~(AV_PIX_FMT_FLAG_PLANAR | AV_PIX_FMT_FLAG_RGB | AV_PIX_FMT_FLAG_PSEUDOPAL | AV_PIX_FMT_FLAG_ALPHA))

         return AVERROR(ENOSYS);

     if (format == AV_PIX_FMT_P010LE || format == AV_PIX_FMT_P010BE)
         return AVERROR(ENOSYS);

     for (i = 0; i < desc->nb_components; i++) {
         c = &desc->comp[i];

         /* for now, only 8-16 bits formats */
         if (c->depth < 8 || c->depth > 16)
             return AVERROR(ENOSYS);
         if (desc->flags & AV_PIX_FMT_FLAG_BE)

             return AVERROR(ENOSYS);
         if (c->plane >= MAX_PLANES)
             return AVERROR(ENOSYS);
         /* strange interleaving */
         if (pixelstep[c->plane] != 0 &&

             pixelstep[c->plane] != c->step)

             return AVERROR(ENOSYS);

         if (pixelstep[c->plane] == 6 &&
             c->depth == 16)
             return AVERROR(ENOSYS);

         pixelstep[c->plane] = c->step;

         if (pixelstep[c->plane] >= 8)
             return AVERROR(ENOSYS);

         nb_planes = FFMAX(nb_planes, c->plane + 1);
     }
     memset(draw, 0, sizeof(*draw));
     draw->desc      = desc;
     draw->format    = format;
     draw->nb_planes = nb_planes;

     draw->flags     = flags;

     memcpy(draw->pixelstep, pixelstep, sizeof(draw->pixelstep));

     draw->hsub[1] = draw->hsub[2] = draw->hsub_max = desc->log2_chroma_w;
     draw->vsub[1] = draw->vsub[2] = draw->vsub_max = desc->log2_chroma_h;

     for (i = 0; i < (desc->nb_components - !!(desc->flags & AV_PIX_FMT_FLAG_ALPHA && !(flags & FF_DRAW_PROCESS_ALPHA))); i++)

         draw->comp_mask[desc->comp[i].plane] |=

             1 << desc->comp[i].offset;

     return 0;
 }
 

 void ff_draw_color(FFDrawContext *draw, FFDrawColor *color, const uint8_t rgba[4])

 {
     unsigned i;
     uint8_t rgba_map[4];
 

     if (rgba != color->rgba)
         memcpy(color->rgba, rgba, sizeof(color->rgba));

     if ((draw->desc->flags & AV_PIX_FMT_FLAG_RGB) &&

         ff_fill_rgba_map(rgba_map, draw->format) >= 0) {

         if (draw->nb_planes == 1) {

             for (i = 0; i < 4; i++) {

                 color->comp[0].u8[rgba_map[i]] = rgba[i];

                 if (draw->desc->comp[rgba_map[i]].depth > 8) {
                     color->comp[0].u16[rgba_map[i]] = color->comp[0].u8[rgba_map[i]] << 8;
                 }
             }

         } else {

             for (i = 0; i < 4; i++) {

                 color->comp[rgba_map[i]].u8[0] = rgba[i];

                 if (draw->desc->comp[rgba_map[i]].depth > 8)
                     color->comp[rgba_map[i]].u16[0] = color->comp[rgba_map[i]].u8[0] << (draw->desc->comp[rgba_map[i]].depth - 8);
             }

         }

     } else if (draw->nb_planes >= 2) {

         /* assume YUV */

         const AVPixFmtDescriptor *desc = draw->desc;
         color->comp[desc->comp[0].plane].u8[desc->comp[0].offset] = RGB_TO_Y_CCIR(rgba[0], rgba[1], rgba[2]);
         color->comp[desc->comp[1].plane].u8[desc->comp[1].offset] = RGB_TO_U_CCIR(rgba[0], rgba[1], rgba[2], 0);
         color->comp[desc->comp[2].plane].u8[desc->comp[2].offset] = RGB_TO_V_CCIR(rgba[0], rgba[1], rgba[2], 0);

         color->comp[3].u8[0] = rgba[3];

 #define EXPAND(compn) \
         if (desc->comp[compn].depth > 8) \
             color->comp[desc->comp[compn].plane].u16[desc->comp[compn].offset] = \

             color->comp[desc->comp[compn].plane].u8[desc->comp[compn].offset] << \
                 (draw->desc->comp[compn].depth + draw->desc->comp[compn].shift - 8)

         EXPAND(3);
         EXPAND(2);
         EXPAND(1);
         EXPAND(0);

     } else if (draw->format == AV_PIX_FMT_GRAY8 || draw->format == AV_PIX_FMT_GRAY8A ||
                draw->format == AV_PIX_FMT_GRAY16LE || draw->format == AV_PIX_FMT_YA16LE ||
                draw->format == AV_PIX_FMT_GRAY9LE  ||
                draw->format == AV_PIX_FMT_GRAY10LE ||
                draw->format == AV_PIX_FMT_GRAY12LE) {
         const AVPixFmtDescriptor *desc = draw->desc;

         color->comp[0].u8[0] = RGB_TO_Y_CCIR(rgba[0], rgba[1], rgba[2]);

         EXPAND(0);

         color->comp[1].u8[0] = rgba[3];

         EXPAND(1);

     } else {
         av_log(NULL, AV_LOG_WARNING,
                "Color conversion not implemented for %s\n", draw->desc->name);
         memset(color, 128, sizeof(*color));
     }
 }
 
 static uint8_t *pointer_at(FFDrawContext *draw, uint8_t *data[], int linesize[],
                            int plane, int x, int y)
 {
     return data[plane] +
            (y >> draw->vsub[plane]) * linesize[plane] +
            (x >> draw->hsub[plane]) * draw->pixelstep[plane];
 }
 
 void ff_copy_rectangle2(FFDrawContext *draw,
                         uint8_t *dst[], int dst_linesize[],
                         uint8_t *src[], int src_linesize[],
                         int dst_x, int dst_y, int src_x, int src_y,
                         int w, int h)
 {
     int plane, y, wp, hp;
     uint8_t *p, *q;
 
     for (plane = 0; plane < draw->nb_planes; plane++) {
         p = pointer_at(draw, src, src_linesize, plane, src_x, src_y);
         q = pointer_at(draw, dst, dst_linesize, plane, dst_x, dst_y);

         wp = AV_CEIL_RSHIFT(w, draw->hsub[plane]) * draw->pixelstep[plane];
         hp = AV_CEIL_RSHIFT(h, draw->vsub[plane]);

         for (y = 0; y < hp; y++) {
             memcpy(q, p, wp);
             p += src_linesize[plane];
             q += dst_linesize[plane];
         }
     }
 }
 
 void ff_fill_rectangle(FFDrawContext *draw, FFDrawColor *color,
                        uint8_t *dst[], int dst_linesize[],
                        int dst_x, int dst_y, int w, int h)
 {
     int plane, x, y, wp, hp;
     uint8_t *p0, *p;

     FFDrawColor color_tmp = *color;

 
     for (plane = 0; plane < draw->nb_planes; plane++) {
         p0 = pointer_at(draw, dst, dst_linesize, plane, dst_x, dst_y);

         wp = AV_CEIL_RSHIFT(w, draw->hsub[plane]);
         hp = AV_CEIL_RSHIFT(h, draw->vsub[plane]);

         if (!hp)
             return;
         p = p0;

 
         if (HAVE_BIGENDIAN && draw->desc->comp[0].depth > 8) {
             for (x = 0; 2*x < draw->pixelstep[plane]; x++)
                 color_tmp.comp[plane].u16[x] = av_bswap16(color_tmp.comp[plane].u16[x]);
         }
 

         /* copy first line from color */
         for (x = 0; x < wp; x++) {

             memcpy(p, color_tmp.comp[plane].u8, draw->pixelstep[plane]);

             p += draw->pixelstep[plane];
         }
         wp *= draw->pixelstep[plane];
         /* copy next lines from first line */
         p = p0 + dst_linesize[plane];
         for (y = 1; y < hp; y++) {
             memcpy(p, p0, wp);
             p += dst_linesize[plane];
         }
     }
 }
 

 /**
  * Clip interval [x; x+w[ within [0; wmax[.
  * The resulting w may be negative if the final interval is empty.
  * dx, if not null, return the difference between in and out value of x.
  */
 static void clip_interval(int wmax, int *x, int *w, int *dx)
 {
     if (dx)
         *dx = 0;
     if (*x < 0) {
         if (dx)
             *dx = -*x;
         *w += *x;
         *x = 0;
     }
     if (*x + *w > wmax)
         *w = wmax - *x;
 }
 
 /**
  * Decompose w pixels starting at x
  * into start + (w starting at x) + end
  * with x and w aligned on multiples of 1<<sub.
  */
 static void subsampling_bounds(int sub, int *x, int *w, int *start, int *end)
 {
     int mask = (1 << sub) - 1;
 
     *start = (-*x) & mask;
     *x += *start;
     *start = FFMIN(*start, *w);
     *w -= *start;
     *end = *w & mask;
     *w >>= sub;
 }
 
 static int component_used(FFDrawContext *draw, int plane, int comp)
 {
     return (draw->comp_mask[plane] >> comp) & 1;
 }
 
 /* If alpha is in the [ 0 ; 0x1010101 ] range,
    then alpha * value is in the [ 0 ; 0xFFFFFFFF ] range,
    and >> 24 gives a correct rounding. */
 static void blend_line(uint8_t *dst, unsigned src, unsigned alpha,
                        int dx, int w, unsigned hsub, int left, int right)
 {
     unsigned asrc = alpha * src;
     unsigned tau = 0x1010101 - alpha;
     int x;
 
     if (left) {
         unsigned suba = (left * alpha) >> hsub;
         *dst = (*dst * (0x1010101 - suba) + src * suba) >> 24;
         dst += dx;
     }
     for (x = 0; x < w; x++) {
         *dst = (*dst * tau + asrc) >> 24;
         dst += dx;
     }
     if (right) {
         unsigned suba = (right * alpha) >> hsub;
         *dst = (*dst * (0x1010101 - suba) + src * suba) >> 24;
     }
 }
 

 static void blend_line16(uint8_t *dst, unsigned src, unsigned alpha,
                          int dx, int w, unsigned hsub, int left, int right)
 {
     unsigned asrc = alpha * src;
     unsigned tau = 0x10001 - alpha;
     int x;
 
     if (left) {
         unsigned suba = (left * alpha) >> hsub;
         uint16_t value = AV_RL16(dst);
         AV_WL16(dst, (value * (0x10001 - suba) + src * suba) >> 16);
         dst += dx;
     }
     for (x = 0; x < w; x++) {
         uint16_t value = AV_RL16(dst);
         AV_WL16(dst, (value * tau + asrc) >> 16);
         dst += dx;
     }
     if (right) {
         unsigned suba = (right * alpha) >> hsub;
         uint16_t value = AV_RL16(dst);
         AV_WL16(dst, (value * (0x10001 - suba) + src * suba) >> 16);
     }
 }
 

 void ff_blend_rectangle(FFDrawContext *draw, FFDrawColor *color,
                         uint8_t *dst[], int dst_linesize[],
                         int dst_w, int dst_h,
                         int x0, int y0, int w, int h)
 {
     unsigned alpha, nb_planes, nb_comp, plane, comp;
     int w_sub, h_sub, x_sub, y_sub, left, right, top, bottom, y;
     uint8_t *p0, *p;
 
     /* TODO optimize if alpha = 0xFF */
     clip_interval(dst_w, &x0, &w, NULL);
     clip_interval(dst_h, &y0, &h, NULL);
     if (w <= 0 || h <= 0 || !color->rgba[3])
         return;

     if (draw->desc->comp[0].depth <= 8) {
         /* 0x10203 * alpha + 2 is in the [ 2 ; 0x1010101 - 2 ] range */
         alpha = 0x10203 * color->rgba[3] + 0x2;
     } else {
         /* 0x101 * alpha is in the [ 2 ; 0x1001] range */
         alpha = 0x101 * color->rgba[3] + 0x2;
     }

     nb_planes = draw->nb_planes - !!(draw->desc->flags & AV_PIX_FMT_FLAG_ALPHA && !(draw->flags & FF_DRAW_PROCESS_ALPHA));

     nb_planes += !nb_planes;

     for (plane = 0; plane < nb_planes; plane++) {
         nb_comp = draw->pixelstep[plane];
         p0 = pointer_at(draw, dst, dst_linesize, plane, x0, y0);
         w_sub = w;
         h_sub = h;
         x_sub = x0;
         y_sub = y0;
         subsampling_bounds(draw->hsub[plane], &x_sub, &w_sub, &left, &right);
         subsampling_bounds(draw->vsub[plane], &y_sub, &h_sub, &top, &bottom);
         for (comp = 0; comp < nb_comp; comp++) {

             const int depth = draw->desc->comp[comp].depth;
 

             if (!component_used(draw, plane, comp))
                 continue;
             p = p0 + comp;
             if (top) {

                 if (depth <= 8) {
                     blend_line(p, color->comp[plane].u8[comp], alpha >> 1,
                                draw->pixelstep[plane], w_sub,
                                draw->hsub[plane], left, right);
                 } else {
                     blend_line16(p, color->comp[plane].u16[comp], alpha >> 1,
                                  draw->pixelstep[plane], w_sub,
                                  draw->hsub[plane], left, right);
                 }

                 p += dst_linesize[plane];
             }

             if (depth <= 8) {
                 for (y = 0; y < h_sub; y++) {
                     blend_line(p, color->comp[plane].u8[comp], alpha,
                                draw->pixelstep[plane], w_sub,
                                draw->hsub[plane], left, right);
                     p += dst_linesize[plane];
                 }
             } else {
                 for (y = 0; y < h_sub; y++) {
                     blend_line16(p, color->comp[plane].u16[comp], alpha,
                                  draw->pixelstep[plane], w_sub,
                                  draw->hsub[plane], left, right);
                     p += dst_linesize[plane];
                 }
             }
             if (bottom) {
                 if (depth <= 8) {
                     blend_line(p, color->comp[plane].u8[comp], alpha >> 1,
                                draw->pixelstep[plane], w_sub,
                                draw->hsub[plane], left, right);
                 } else {
                     blend_line16(p, color->comp[plane].u16[comp], alpha >> 1,
                                  draw->pixelstep[plane], w_sub,
                                  draw->hsub[plane], left, right);
                 }

             }
         }
     }
 }
 

 static void blend_pixel16(uint8_t *dst, unsigned src, unsigned alpha,
                           const uint8_t *mask, int mask_linesize, int l2depth,
                           unsigned w, unsigned h, unsigned shift, unsigned xm0)
 {
     unsigned xm, x, y, t = 0;
     unsigned xmshf = 3 - l2depth;
     unsigned xmmod = 7 >> l2depth;
     unsigned mbits = (1 << (1 << l2depth)) - 1;
     unsigned mmult = 255 / mbits;
     uint16_t value = AV_RL16(dst);
 
     for (y = 0; y < h; y++) {
         xm = xm0;
         for (x = 0; x < w; x++) {
             t += ((mask[xm >> xmshf] >> ((~xm & xmmod) << l2depth)) & mbits)
                  * mmult;
             xm++;
         }
         mask += mask_linesize;
     }
     alpha = (t >> shift) * alpha;
     AV_WL16(dst, ((0x10001 - alpha) * value + alpha * src) >> 16);
 }
 

 static void blend_pixel(uint8_t *dst, unsigned src, unsigned alpha,

                         const uint8_t *mask, int mask_linesize, int l2depth,

                         unsigned w, unsigned h, unsigned shift, unsigned xm0)
 {
     unsigned xm, x, y, t = 0;
     unsigned xmshf = 3 - l2depth;
     unsigned xmmod = 7 >> l2depth;
     unsigned mbits = (1 << (1 << l2depth)) - 1;
     unsigned mmult = 255 / mbits;
 
     for (y = 0; y < h; y++) {
         xm = xm0;
         for (x = 0; x < w; x++) {
             t += ((mask[xm >> xmshf] >> ((~xm & xmmod) << l2depth)) & mbits)
                  * mmult;
             xm++;
         }
         mask += mask_linesize;
     }
     alpha = (t >> shift) * alpha;
     *dst = ((0x1010101 - alpha) * *dst + alpha * src) >> 24;
 }
 

 static void blend_line_hv16(uint8_t *dst, int dst_delta,
                             unsigned src, unsigned alpha,
                             const uint8_t *mask, int mask_linesize, int l2depth, int w,
                             unsigned hsub, unsigned vsub,
                             int xm, int left, int right, int hband)
 {
     int x;
 
     if (left) {
         blend_pixel16(dst, src, alpha, mask, mask_linesize, l2depth,
                       left, hband, hsub + vsub, xm);
         dst += dst_delta;
         xm += left;
     }
     for (x = 0; x < w; x++) {
         blend_pixel16(dst, src, alpha, mask, mask_linesize, l2depth,
                       1 << hsub, hband, hsub + vsub, xm);
         dst += dst_delta;
         xm += 1 << hsub;
     }
     if (right)
         blend_pixel16(dst, src, alpha, mask, mask_linesize, l2depth,
                       right, hband, hsub + vsub, xm);
 }
 

 static void blend_line_hv(uint8_t *dst, int dst_delta,
                           unsigned src, unsigned alpha,

                           const uint8_t *mask, int mask_linesize, int l2depth, int w,

                           unsigned hsub, unsigned vsub,
                           int xm, int left, int right, int hband)
 {
     int x;
 
     if (left) {
         blend_pixel(dst, src, alpha, mask, mask_linesize, l2depth,
                     left, hband, hsub + vsub, xm);
         dst += dst_delta;
         xm += left;
     }
     for (x = 0; x < w; x++) {
         blend_pixel(dst, src, alpha, mask, mask_linesize, l2depth,
                     1 << hsub, hband, hsub + vsub, xm);
         dst += dst_delta;
         xm += 1 << hsub;
     }
     if (right)
         blend_pixel(dst, src, alpha, mask, mask_linesize, l2depth,
                     right, hband, hsub + vsub, xm);
 }
 
 void ff_blend_mask(FFDrawContext *draw, FFDrawColor *color,
                    uint8_t *dst[], int dst_linesize[], int dst_w, int dst_h,

                    const uint8_t *mask,  int mask_linesize, int mask_w, int mask_h,

                    int l2depth, unsigned endianness, int x0, int y0)
 {
     unsigned alpha, nb_planes, nb_comp, plane, comp;
     int xm0, ym0, w_sub, h_sub, x_sub, y_sub, left, right, top, bottom, y;

     uint8_t *p0, *p;
     const uint8_t *m;

 
     clip_interval(dst_w, &x0, &mask_w, &xm0);
     clip_interval(dst_h, &y0, &mask_h, &ym0);
     mask += ym0 * mask_linesize;
     if (mask_w <= 0 || mask_h <= 0 || !color->rgba[3])
         return;

     if (draw->desc->comp[0].depth <= 8) {
         /* alpha is in the [ 0 ; 0x10203 ] range,
            alpha * mask is in the [ 0 ; 0x1010101 - 4 ] range */
         alpha = (0x10307 * color->rgba[3] + 0x3) >> 8;
     } else {
         alpha = (0x101 * color->rgba[3] + 0x2) >> 8;
     }

     nb_planes = draw->nb_planes - !!(draw->desc->flags & AV_PIX_FMT_FLAG_ALPHA && !(draw->flags & FF_DRAW_PROCESS_ALPHA));

     nb_planes += !nb_planes;

     for (plane = 0; plane < nb_planes; plane++) {
         nb_comp = draw->pixelstep[plane];
         p0 = pointer_at(draw, dst, dst_linesize, plane, x0, y0);
         w_sub = mask_w;
         h_sub = mask_h;
         x_sub = x0;
         y_sub = y0;
         subsampling_bounds(draw->hsub[plane], &x_sub, &w_sub, &left, &right);
         subsampling_bounds(draw->vsub[plane], &y_sub, &h_sub, &top, &bottom);
         for (comp = 0; comp < nb_comp; comp++) {

             const int depth = draw->desc->comp[comp].depth;
 

             if (!component_used(draw, plane, comp))
                 continue;
             p = p0 + comp;
             m = mask;
             if (top) {

                 if (depth <= 8) {
                     blend_line_hv(p, draw->pixelstep[plane],
                                   color->comp[plane].u8[comp], alpha,
                                   m, mask_linesize, l2depth, w_sub,
                                   draw->hsub[plane], draw->vsub[plane],
                                   xm0, left, right, top);
                 } else {
                     blend_line_hv16(p, draw->pixelstep[plane],
                                     color->comp[plane].u16[comp], alpha,
                                     m, mask_linesize, l2depth, w_sub,
                                     draw->hsub[plane], draw->vsub[plane],
                                     xm0, left, right, top);
                 }

                 p += dst_linesize[plane];
                 m += top * mask_linesize;
             }

             if (depth <= 8) {
                 for (y = 0; y < h_sub; y++) {
                     blend_line_hv(p, draw->pixelstep[plane],
                                   color->comp[plane].u8[comp], alpha,
                                   m, mask_linesize, l2depth, w_sub,
                                   draw->hsub[plane], draw->vsub[plane],
                                   xm0, left, right, 1 << draw->vsub[plane]);
                     p += dst_linesize[plane];
                     m += mask_linesize << draw->vsub[plane];
                 }
             } else {
                 for (y = 0; y < h_sub; y++) {
                     blend_line_hv16(p, draw->pixelstep[plane],
                                     color->comp[plane].u16[comp], alpha,
                                     m, mask_linesize, l2depth, w_sub,
                                     draw->hsub[plane], draw->vsub[plane],
                                     xm0, left, right, 1 << draw->vsub[plane]);
                     p += dst_linesize[plane];
                     m += mask_linesize << draw->vsub[plane];
                 }
             }
             if (bottom) {
                 if (depth <= 8) {
                     blend_line_hv(p, draw->pixelstep[plane],
                                   color->comp[plane].u8[comp], alpha,
                                   m, mask_linesize, l2depth, w_sub,
                                   draw->hsub[plane], draw->vsub[plane],
                                   xm0, left, right, bottom);
                 } else {
                     blend_line_hv16(p, draw->pixelstep[plane],
                                     color->comp[plane].u16[comp], alpha,
                                     m, mask_linesize, l2depth, w_sub,
                                     draw->hsub[plane], draw->vsub[plane],
                                     xm0, left, right, bottom);
                 }

             }
         }
     }
 }
 

 int ff_draw_round_to_sub(FFDrawContext *draw, int sub_dir, int round_dir,
                          int value)
 {
     unsigned shift = sub_dir ? draw->vsub_max : draw->hsub_max;
 
     if (!shift)
         return value;
     if (round_dir >= 0)
         value += round_dir ? (1 << shift) - 1 : 1 << (shift - 1);
     return (value >> shift) << shift;
 }
 
 AVFilterFormats *ff_draw_supported_pixel_formats(unsigned flags)
 {

     enum AVPixelFormat i;

     FFDrawContext draw;

     AVFilterFormats *fmts = NULL;

     int ret;

     for (i = 0; av_pix_fmt_desc_get(i); i++)

         if (ff_draw_init(&draw, i, flags) >= 0 &&
             (ret = ff_add_format(&fmts, i)) < 0)
             return NULL;

     return fmts;

 }