doc/filters: document drawtext draw expression

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Stefano Sabatini 2012-05-01 13:26:05 +02:00
parent eb07f4ccb5
commit 4f19e50c23
1 changed files with 16 additions and 0 deletions

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@ -1273,6 +1273,16 @@ Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
(e.g. "0xff00ff"), possibly followed by an alpha specifier.
The default value of @var{boxcolor} is "white".
@item draw
Set an expression which specifies if the text should be drawn. If the
expression evaluates to 0, the text is not drawn. This is useful for
specifying that the text should be drawn only when specific conditions
are met.
Default value is "1".
See below for the list of accepted constants and functions.
@item fix_bounds
If true, check and fix text coords to avoid clipping.
@ -1490,6 +1500,12 @@ The glyph baseline is placed at half screen height.
drawtext=fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent
@end example
@item
Show text for 1 second every 3 seconds:
@example
drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:draw=lt(mod(t\\,3)\\,1):text='blink'"
@end example
@item
Use fontconfig to set the font. Note that the colons need to be escaped.
@example