0x.RetimeKara.lua

local tr = aegisub.gettext

script_name = tr'k-retime'
script_description = tr'Set start/end timestamps while preserving syl timing'
script_author = 'The0x539'
script_version = '0.1.0'
script_namespace = '0x.k-retime'

local DependencyControl = require 'l0.DependencyControl'
local rec = DependencyControl {
	feed = 'https://raw.githubusercontent.com/TypesettingTools/line0-Aegisub-Scripts/master/DependencyControl.json',
	{{"a-mo.LineCollection", version = "1.0.1", url = "https://github.com/TypesettingTools/Aegisub-Motion",
	  feed = "https://raw.githubusercontent.com/TypesettingTools/Aegisub-Motion/DepCtrl/DependencyControl.json"},
	 {"l0.ASSFoundation", version = "0.2.2", url = "https://github.com/TypesettingTools/ASSFoundation",
	  feed = "https://raw.githubusercontent.com/TypesettingTools/ASSFoundation/master/DependencyControl.json"}
	}
}
local LineCollection, assf = rec:requireModules()

local function process(line, delta_start, delta_end)
	if delta_start % 10 ~= 0 or delta_end % 10 ~= 0 then
		error('deltas must not have millisecond precision')
	end

	line.start_time = line.start_time + delta_start
	line.end_time = line.end_time + delta_end

	local data = assf:parse(line)
	local ktags = data:getTags({'k_fill', 'k_sweep', 'k_bord'})

	if #ktags > 0 then
		ktags[1].value = ktags[1].value - delta_start
		ktags[#ktags].value = ktags[#ktags].value + delta_end
	end

	data:commit()
end

local function process_all(subs, sel, changing_start)
	local video_position = aegisub.ms_from_frame(aegisub.project_properties().video_position)
	video_position = video_position - (video_position % 10)

	local function cb(_, line, _)
		local delta_start, delta_end = 0, 0
		if changing_start then
			delta_start = video_position - line.start_time
		else
			delta_end = video_position - line.end_time
		end
		process(line, delta_start, delta_end)
	end
	
	local lines = LineCollection(subs, sel, function() --[[this is so dumb]] return true end)
	lines:runCallback(cb)
	lines:replaceLines()
end

local function set_start(subs, sel, i)
	process_all(subs, sel, true)
	aegisub.set_undo_point('Snap start to video, preserving k-timing')
end

local function set_end(subs, sel, i)
	process_all(subs, sel, false)
	aegisub.set_undo_point('Snap end to video, preserving k-timing')
end

aegisub.register_macro('k-retime/Set Start', script_description, set_start)
aegisub.register_macro('k-retime/Set End', script_description, set_end)