From a228af752a5b37bf3ba0654083e9495d5aa4b86b Mon Sep 17 00:00:00 2001
From: Niels Martin Hansen <nielsm@aegisub.org>
Date: Wed, 29 Aug 2007 22:29:46 +0000
Subject: [PATCH] Some non-tested non-complete and probably non-useful (yet)
 code to handle SSA-lineage files.

Originally committed to SVN as r1546.
---
 OverLua/luasupport/assfile.lua | 134 +++++++++++++++++++++++++++++++++
 OverLua/luasupport/readme.txt  |   1 +
 2 files changed, 135 insertions(+)
 create mode 100644 OverLua/luasupport/assfile.lua
 create mode 100644 OverLua/luasupport/readme.txt

diff --git a/OverLua/luasupport/assfile.lua b/OverLua/luasupport/assfile.lua
new file mode 100644
index 000000000..432a24215
--- /dev/null
+++ b/OverLua/luasupport/assfile.lua
@@ -0,0 +1,134 @@
+--[[
+	assfile.lua - Functions for parsing ASS format subtitles
+	Part of OverLua, licensed under GPLv2
+]]
+
+module "assfile"
+
+
+-- Parsing helper functions
+local function trim(s)
+	return (s:gsub("^[ \t\r\n]*(.-)[ \t\r\n]*$", "%1"))
+end
+local function num(s)
+	return tonumber(trim(s)) or 0
+end
+
+
+-- Which file format we're working with.
+-- Changing this changes the behaviour of various parsing functions.
+-- Valid values: "SSA4", "ASS", "ASS2", "ASS3", "AS5"
+-- Other versions aren't supported.
+-- This is usually automatically set by the whole-file parsing functions.
+format = "SSA4"
+
+
+-- Create a solid colour fill style
+-- Colours are "cairo compatible", ie. range 0 to 1
+-- A colour never stores alpha, that's a separate property
+function color(r, g, b, a)
+	r, g, b, a = r or 0, g or 0, b or 0, a or 0
+	return {class="solid", r=r, g=g, b=b, a=a}
+end
+
+-- Parse a colour in SSA, ASS or HTML format
+function parse_color(s)
+end
+
+
+-- Base style, this defines the defaults used for undefined fields in read-in styles
+default_style = {
+	-- Default style has no name
+	name = nil,
+	-- Well, sensible on Windows
+	font_face = "Arial",
+	font_size = "24",
+	font_language = "C", -- Language to assume text is in, affects some rendering
+	font_vertical = false, -- Vertical layout, replaces use of "@-fonts"
+	font_bold = false,
+	font_italic = false,
+	font_underline = false,
+	font_overstrike = false,
+	-- Fill style
+	fill1 = color(1, 1, 1, 1), -- Fill, white
+	fill2 = color(1, 0, 0, 1), -- Pre-karaoke fill, red
+	fill3 = color(0, 0, 0, 1), -- Outline, black
+	fill4 = color(0, 0, 0, 0.5), -- Shadow, semi-transparent black
+	-- Border size
+	outline = 2,
+	shadow = 2,
+	opaque_box = false,
+	-- Scaling
+	scale_x = 1.00,
+	scale_y = 1.00,
+	-- Spacing
+	spacing_char = 0, -- Extra inter-character spacing
+	spacing_line = 0, -- Extra inter-line spacing
+	baseline_shift = 0, -- Shift baseline this amount against line advance direction
+	-- Text positioning
+	margin_l = 10,
+	margin_r = 10,
+	margin_t = 10,
+	margin_b = 10,
+	align_x = 0.5, -- Bouding box centered between left/right margins
+	align_y = 1.0, -- Bounding box placed at bottom of screen
+	inner_align_x = 0.5, -- Lines centered inside bounding box
+	inner_align_y = 1.0, -- Lines at bottom of bounding box
+	break_style = "smart_top", -- "Smart-wrap", earlier lines wider (alt. "smart_bottom", "simple", "none")
+	pos_rel = "video", -- Positioning relative to video frame (alt. "screen")
+	pos_x = nil, -- Don't override positioning
+	pos_y = nil,
+	-- Rotation/reshaping
+	origin = nil, -- Automatic, at center of text
+	angle_x = 0,
+	angle_y = 0,
+	angle_z = 0,
+	shear_x = 0,
+	shear_y = 0,
+	baseline_transform = nil,
+	bounding_box_transform = nil,
+	-- Misc.
+	blend_mode = "normal", -- Alt. "add", "multiply"
+	clip_rect = nil,
+	clip_shape = nil,
+	blur = 0,
+	-- Animation
+	fade = nil,
+	animation = nil
+}
+
+
+-- Parse a Style line
+function read_style(t)
+	if format == "AS5" then
+		error("Found Style line in an AS5 file, where it's unsupported.\nLine: %s", t)
+	
+	elseif format == "SSA4" then
+		local name, font_face, font_size, color1, color2, color3, color4,
+			bold, italic, underline, overstrike, border, outline, shadow,
+			align, margin_l, margin_r, margin_v, alpha, encoding
+			= t:match("^.-:(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-),(.-)$")
+		name = trim(name)
+		font_face = trim(name)
+		font_size = num(font_size)
+	end
+end
+
+
+-- Parse a StyleEx line
+function read_style_ex(t)
+	if format ~= "ASS3" and format ~= "AS5" then
+		error("Found StyleEx line in format that doesn't support it.\nFormat is \"%s\".\nLine is: %s", format, t)
+	end
+end
+
+
+-- Merge two styles by "overlaying" a style upon a base
+-- Produces a new style
+-- Fields where the overlay has a defined value, the output style has the value of overlay,
+-- but in fields where overlay is nil, the output has the base value.
+-- (Pretty much "out.field = overlay.field or base.field".)
+-- Animation lists are merged however, but this may produce weird results
+-- if the animations overlap in non-trivial ways. (Just pretend this says "undefined behaviour.")
+function merge_styles(base, overlay)
+end
diff --git a/OverLua/luasupport/readme.txt b/OverLua/luasupport/readme.txt
new file mode 100644
index 000000000..6ad416ce8
--- /dev/null
+++ b/OverLua/luasupport/readme.txt
@@ -0,0 +1 @@
+This directory contains various helper scripts for use with OverLua.