[FFmpeg-devel] [PATCH] lavfi/drawbox: implement color=invert mode

[Stefano Sabatini]

On date Tuesday 2012-10-30 21:25:47 +0100, Clément Bœsch encoded:
> On Tue, Oct 30, 2012 at 08:14:46PM +0100, Stefano Sabatini wrote:
> > Based on libmpcodecs/vf_rectangle.c feature.
> > ---
> >  doc/filters.texi         |    4 +++-
> >  libavfilter/vf_drawbox.c |   12 +++++++++++-
> >  2 files changed, 14 insertions(+), 2 deletions(-)
> > 
> > diff --git a/doc/filters.texi b/doc/filters.texi
> > index 73d007a..29548ae 100644
> > --- a/doc/filters.texi
> > +++ b/doc/filters.texi
> > @@ -1741,7 +1741,9 @@ the input width and height. Default to 0.
> >  
> >  @item color
> >  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.
> 

> Any reason to just set this mode by default (since it helps visibility
> most of the time) unless the user explicits a color?

To not break backward compatibility.

> 
> >  @end table
> >  
> >  If the key of the first options is omitted, the arguments are
> > diff --git a/libavfilter/vf_drawbox.c b/libavfilter/vf_drawbox.c
> > index be55d54..f3dd141 100644
> > --- a/libavfilter/vf_drawbox.c
> > +++ b/libavfilter/vf_drawbox.c
> > @@ -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;
> >  
> > @@ -71,7 +72,9 @@ 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]);
> > @@ -134,6 +137,12 @@ 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++)
> 
> () look pointless

Will fix in a later commit.
 
> > +                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;
> >  
> > @@ -144,6 +153,7 @@ 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);
> 
> LGTM otherwise

Applied.
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