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| author | yethie <klimklim@tiscali.it> | 2023-05-26 12:46:10 +0200 |
|---|---|---|
| committer | Paul B Mahol <onemda@gmail.com> | 2023-06-19 22:35:53 +0200 |
| commit | 01d843f6d09b94f6f424d4d408ca2fc92dcaefd7 (patch) | |
| tree | 8b7945273d3ae9bf464d3063d7d5016a2dfff491 | |
| parent | fac7bb06d86ab8a82adfa50c4b1f2348427af55b (diff) | |
| download | ffmpeg-01d843f6d09b94f6f424d4d408ca2fc92dcaefd7.tar.gz | |
avfilter/vf_drawtext: add expression variables to control font ascent/descent
The following new variables can be used in the x and y expressions: font_a, font_d, top_a, bottom_d.
| -rw-r--r-- | doc/filters.texi | 12 | ||||
| -rw-r--r-- | libavfilter/vf_drawtext.c | 12 |
2 files changed, 24 insertions, 0 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index 97fec936a4..da355eca64 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -12597,6 +12597,18 @@ contained in the rendered text, it is equivalent to @var{ascent} - maximum glyph width, that is the maximum width for all the glyphs contained in the rendered text +@item font_a +the ascent size defined in the font metrics + +@item font_d +the descent size defined in the font metrics + +@item top_a +the maximum ascender of the glyphs of the first text line + +@item bottom_d +the maximum descender of the glyphs of the last text line + @item n the number of input frame, starting from 0 diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c index b971eebdf4..417733596d 100644 --- a/libavfilter/vf_drawtext.c +++ b/libavfilter/vf_drawtext.c @@ -89,6 +89,10 @@ static const char *const var_names[] = { "max_glyph_d", "descent", ///< min glyph descender "max_glyph_h", ///< max glyph height "max_glyph_w", ///< max glyph width + "font_a", ///< font-defined ascent + "font_d", ///< font-defined descent + "top_a", ///< max glyph ascender of the top line + "bottom_d", ///< max glyph descender of the bottom line "n", ///< number of frame "sar", "t", ///< timestamp expressed in seconds @@ -136,6 +140,10 @@ enum var_name { VAR_MAX_GLYPH_D, VAR_DESCENT, VAR_MAX_GLYPH_H, VAR_MAX_GLYPH_W, + VAR_FONT_A, + VAR_FONT_D, + VAR_TOP_A, + VAR_BOTTOM_D, VAR_N, VAR_SAR, VAR_T, @@ -1800,8 +1808,12 @@ static int draw_text(AVFilterContext *ctx, AVFrame *frame) s->var_values[VAR_MAX_GLYPH_W] = s->max_glyph_w; s->var_values[VAR_MAX_GLYPH_H] = s->max_glyph_h; s->var_values[VAR_MAX_GLYPH_A] = s->var_values[VAR_ASCENT] = POS_CEIL(metrics.max_y64, 64); + s->var_values[VAR_FONT_A] = s->face->size->metrics.ascender / 64; s->var_values[VAR_MAX_GLYPH_D] = s->var_values[VAR_DESCENT] = POS_CEIL(metrics.min_y64, 64); + s->var_values[VAR_FONT_D] = -s->face->size->metrics.descender / 64; + s->var_values[VAR_TOP_A] = POS_CEIL(metrics.offset_top64, 64); + s->var_values[VAR_BOTTOM_D] = -POS_CEIL(metrics.offset_bottom64, 64); s->var_values[VAR_LINE_H] = s->var_values[VAR_LH] = metrics.line_height64 / 64.; if (s->text_source == AV_FRAME_DATA_DETECTION_BBOXES) { |