[FFmpeg-devel] [PATCH] vf_drawtext: make x and y options parametric

Stefano Sabatini stefasab at gmail.com
Fri Sep 23 02:41:26 CEST 2011


On date Thursday 2011-09-22 01:14:12 +0200, Stefano Sabatini encoded:
> On date Wednesday 2011-09-21 22:14:26 +0200, Víctor Paesa encoded:
> > Hi,
[...]
> > So the example (ruining parametric horizontal centering) is:
> > drawtext=fontsize=30:fontfile=FreeSerif.ttf:fontcolor=green:text='g':x=w/2:y=(h-text_h+ascent-line_h)/2
> > drawtext=fontsize=30:fontfile=FreeSerif.ttf:fontcolor=red:text='ood':x=w/2+22:y=(h-text_h+ascent-line_h)/2
> 
> Updated work in progress, not still ready for commit with a few fixes
> and the addition of the ascent/descent/max_glyph_w constants.
> 
> Still missing:
> 
> * documentation for the new variables (in particular about the meaning
>   of ascent/descent)
> 
> * better names or short aliases for max_glyph_h/w (suggestions are
>   welcome...), also max_glyph_h == line_h so maybe I should keep an
>   alias for that

Nit, now we have:
"max_glyph_w",   ///< max glyph width
"max_glyph_h",   ///< max glyph height
"ascent",        ///< max glyph ascent
"descent",       ///< max glyph descent

maybe a better scheme could be:
max_glyph_w
max_glyph_h
max_glyph_a
max_glyph_d

Opinions?

> * figure out how to deal with the wrapline feature, I don't think it
>   is possible to conciliate it easily with moving x/y, but I see it is
>   useful under certain scenarios so I'd like to keep it at least as a
>   tweakable option.

I made my mind, and I believe it's better to drop it at all, rather
than leave it half-implement, drawtext is not supposed to be a word
processor, and having an half-baked wrapping feature is not going to
help in that sense, and drawtext is just supposed to be a thin wrapper
around the libfreetype capabilities, we may add a text processing
filter as a separate filter (e.g. wrapping imagemagik or even an HTML
renderer).

Updated.
-- 
FFmpeg = Fabulous and Friendly Mournful Problematic Ecletic Gymnast
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