diff options
Diffstat (limited to 'lib')
-rw-r--r-- | lib/dtas/fadefx.rb | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/lib/dtas/fadefx.rb b/lib/dtas/fadefx.rb new file mode 100644 index 0000000..1ef79ef --- /dev/null +++ b/lib/dtas/fadefx.rb @@ -0,0 +1,44 @@ +# Copyright (C) 2013-2015, all contributors <dtas-all@nongnu.org> +# License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt) +require_relative '../dtas' +require_relative 'parse_time' + +# --------- time ---------> +# _____ _______ ______ +# \ / \ / +# prev X cur X next +# _____/ \_______/ \______ +# +# out_prev - controls the downward slope from prev +# in_cur - controls the upward slope into cur +# out_cur - controls the downward slope from cur +# in_next - controls the upward slope into next +class DTAS::FadeFX # :nodoc: + include DTAS::ParseTime + + attr_reader :out_prev, :in_cur, :out_cur, :in_next + F = Struct.new(:type, :flen) + + def initialize(args) + args =~ /\A([^,]*),([^,]*);([^,]*),([^,]*)\z/ or + raise ArgumentError, "bad fade format" + fades = [ $1, $2, $3, $4 ] + %w(out_prev in_cur out_cur in_next).each do |iv| + instance_variable_set("@#{iv}", parse!(fades.shift)) + end + end + + # q - quarter of a sine wave + # h - half a sine wave + # t - linear (`triangular') slope + # l - logarithmic + # p - inverted parabola + # default is 't' (sox defaults to 'l', but triangular makes more sense + # when concatenating + def parse!(str) + return nil if str.empty? + type = "t" + str.sub!(/\A([a-z])/, "") and type = $1 + F.new(type, parse_time(str)) + end +end |