mirror of https://github.com/odrling/Aegisub
135 lines
4.2 KiB
Lua
135 lines
4.2 KiB
Lua
--[[
|
|
|
|
Sample script for OverLua
|
|
- demonstrate basic reading in an ASS subtitle file and rendering its lines on the video
|
|
|
|
Given into the public domain.
|
|
(You can do anything you want with this file, with no restrictions whatsoever.
|
|
You don't get any warranties of any kind either, though.)
|
|
|
|
Originally authored by Niels Martin Hansen.
|
|
|
|
]]
|
|
|
|
-- overlua_datastring is the string given to data= argument in Avisynth filter invocation
|
|
timing_input_file = overlua_datastring
|
|
-- You may want to get these from somewhere else
|
|
-- Or just stick to hardcoding all styling information
|
|
font_name = "Arial"
|
|
font_size = 24
|
|
|
|
-- A little check that an input file was actually given
|
|
assert(timing_input_file, "Missing input file")
|
|
|
|
|
|
-- An easier way to convert a string to a number and be guaranteed to get something useful
|
|
function parsenum(str)
|
|
return tonumber(str) or 0
|
|
end
|
|
-- Convert an ASS timestamp into a number of seconds
|
|
function parse_ass_time(ass)
|
|
local h, m, s, cs = ass:match("(%d+):(%d+):(%d+)%.(%d+)")
|
|
return parsenum(cs)/100 + parsenum(s) + parsenum(m)*60 + parsenum(h)*3600
|
|
end
|
|
|
|
-- Not used here, but do some basic \k timing parsing
|
|
function parse_k_timing(text)
|
|
local syls = {}
|
|
local i = 1
|
|
for timing, syltext in text:gmatch("{\\k(%d+)}([^{]*)") do
|
|
local syl = {dur = parsenum(timing)/100, text = syltext, i = i}
|
|
table.insert(syls, syl)
|
|
i = i + 1
|
|
end
|
|
return syls
|
|
end
|
|
|
|
-- Really stupid ASS parser
|
|
function read_input_file(name)
|
|
for line in io.lines(name) do
|
|
-- You can catch Style lines in the same way if you want
|
|
local start_time, end_time, style, fx, text = line:match("Dialogue: 0,(.-),(.-),(.-),.-,0000,0000,0000,(.-),(.*)")
|
|
if text then
|
|
local ls = {}
|
|
ls.start_time = parse_ass_time(start_time)
|
|
ls.end_time = parse_ass_time(end_time)
|
|
ls.style = style
|
|
ls.fx = fx
|
|
ls.rawtext = text
|
|
ls.kara = parse_k_timing(text)
|
|
-- Clear out override blocks
|
|
ls.cleantext = text:gsub("{.-}", "")
|
|
table.insert(lines, ls)
|
|
end
|
|
end
|
|
end
|
|
|
|
-- Initialisation function, intended to be run on the first frame
|
|
-- I think it's better to delay initialisation until first frame is requested
|
|
-- rather than doing it immediately at load time.
|
|
-- I believe much encoding software might be more graceful about that.
|
|
function init()
|
|
if inited then return end
|
|
inited = true
|
|
|
|
lines = {}
|
|
read_input_file(timing_input_file)
|
|
end
|
|
|
|
|
|
-- Actual work function, this is what's called by OverLua for each frame
|
|
-- f is a video frame object, what we'll be drawing to
|
|
-- t is the timestamp of the frame, given in seconds (floating point)
|
|
function render_frame(f, t)
|
|
-- Just call init() every time, init itself makes sure it doesn't init more than once
|
|
init()
|
|
|
|
-- Find lines to be drawn
|
|
-- NOTE: This structure is very simplistic.
|
|
-- Advanced karaoke effects will probably need to build an object/effect list
|
|
-- as initialisation and then instead go over the list of objects/effects per frame,
|
|
-- instead of going over lines.
|
|
-- (Ie. preprocessing in the style of ASS karaoke generation.)
|
|
for i, line in pairs(lines) do
|
|
if line.start_time <= t and line.end_time > t then
|
|
-- Initial position of line
|
|
local x = 0
|
|
local y = f.height - 25
|
|
|
|
-- Initialise drawing surface and context
|
|
local surf = cairo.image_surface_create(f.width, f.height, "argb32")
|
|
local c = surf.create_context()
|
|
|
|
-- Select our font
|
|
c.select_font_face(font_name)
|
|
c.set_font_size(font_size)
|
|
|
|
-- Get sizing information for font and line text
|
|
if not line.te then line.te = c.text_extents(line.cleantext); line.fe = c.font_extents() end
|
|
-- Calculate centered position
|
|
x = (f.width - line.te.width) / 2 - line.te.x_bearing
|
|
|
|
-- Produce text path
|
|
c.move_to(x, y)
|
|
c.text_path(line.cleantext)
|
|
|
|
-- Draw a black border
|
|
-- It will be centered on the text outline
|
|
c.set_line_width(4)
|
|
c.set_line_join("round") -- default is "miter"
|
|
c.set_source_rgba(0, 0, 0, 1)
|
|
-- "preserve" to keep the text path in the context
|
|
c.stroke_preserve()
|
|
-- Apply a little box blur to the border, effectively \be1
|
|
raster.box_blur(surf, 3)
|
|
|
|
-- Draw a white fill - this will draw over the inner part of the border
|
|
c.set_source_rgba(1, 1, 1, 1)
|
|
c.fill()
|
|
|
|
-- Overlay on video
|
|
f.overlay_cairo_surface(surf, 0, 0)
|
|
end
|
|
end
|
|
end
|