@@ -1741,7 +1741,9 @@ the input width and height. Default to 0.

 @item color, c

 Specify the color of the box to write, it can be the name of a color

-(case insensitive match) or a 0xRRGGBB[AA] sequence.

+(case insensitive match) or a 0xRRGGBB[AA] sequence. If the special

+value @code{invert} is used, the box edge color is the same as the

+video with inverted luma.

 @end table

 If the key of the first options is omitted, the arguments are

@@ -30,7 +30,7 @@

 #define LIBAVFILTER_VERSION_MAJOR  3

 #define LIBAVFILTER_VERSION_MINOR  21

-#define LIBAVFILTER_VERSION_MICRO 101

+#define LIBAVFILTER_VERSION_MICRO 102

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

                                                LIBAVFILTER_VERSION_MINOR, \

@@ -41,6 +41,7 @@ typedef struct {

     int x, y, w, h;

     char *color_str;

     unsigned char yuv_color[4];

+    int invert_color; ///< invert luma color

     int vsub, hsub;   ///< chroma subsampling

 } DrawBoxContext;

@@ -72,7 +73,9 @@ static av_cold int init(AVFilterContext *ctx, const char *args)

     if ((ret = av_opt_set_from_string(drawbox, args, shorthand, "=", ":")) < 0)

         return ret;

-    if (av_parse_color(rgba_color, drawbox->color_str, -1, ctx) < 0)

+    if (!strcmp(drawbox->color_str, "invert"))

+        drawbox->invert_color = 1;

+    else if (av_parse_color(rgba_color, drawbox->color_str, -1, ctx) < 0)

         return AVERROR(EINVAL);

     drawbox->yuv_color[Y] = RGB_TO_Y_CCIR(rgba_color[0], rgba_color[1], rgba_color[2]);

@@ -135,6 +138,12 @@ static int draw_slice(AVFilterLink *inlink, int y0, int h, int slice_dir)

             row[plane] = picref->data[plane] +

                 picref->linesize[plane] * (y >> drawbox->vsub);

+        if (drawbox->invert_color) {

+            for (x = FFMAX(xb, 0); x < (xb + drawbox->w) && x < picref->video->w; x++)

+                if ((y - yb < 3) || (yb + drawbox->h - y < 4) ||

+                    (x - xb < 3) || (xb + drawbox->w - x < 4))

+                    row[0][x] = 0xff - row[0][x];

+        } else {

         for (x = FFMAX(xb, 0); x < (xb + drawbox->w) && x < picref->video->w; x++) {

             double alpha = (double)drawbox->yuv_color[A] / 255;

@@ -145,6 +154,7 @@ static int draw_slice(AVFilterLink *inlink, int y0, int h, int slice_dir)

                 row[2][x >> drawbox->hsub] = (1 - alpha) * row[2][x >> drawbox->hsub] + alpha * drawbox->yuv_color[V];

             }

         }

+        }

     }

     return ff_draw_slice(inlink->dst->outputs[0], y0, h, 1);