Aegisub/automation/include/utils.lua

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--[[
Copyright (c) 2005-2006, Niels Martin Hansen, Rodrigo Braz Monteiro
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* Neither the name of the Aegisub Group nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
]]
-- Compatibility hatch
if aegisub.lua_automation_version < 4 then
include "utils.auto3"
return
end
-- Make a shallow copy of a table
function table.copy(oldtab)
local newtab = {}
for key, val in pairs(oldtab) do
newtab[key] = val
end
return newtab
end
-- Compability
copy_line = table.copy
-- Make a deep copy of a table
-- This will do infinite recursion if there's any circular references. (Eg. if you try to copy _G)
function table.copy_deep(srctab)
-- Table to hold subtables already copied, to avoid circular references causing infinite recursion
local circular = {}
local function do_copy(oldtab)
local newtab = {}
for key, val in pairs(newtab) do
if type(val) == "table" then
if not circular[val] then
circular[val] = do_copy(val)
end
newtab[key] = circular[val]
else
newtab[key] = val
end
end
end
return do_copy(srctab)
end
-- Generates ASS hexadecimal string from R,G,B integer components, in &HBBGGRR& format
function ass_color(r,g,b)
return string.format("&H%02X%02X%02X&",b,g,r)
end
-- Format an alpha-string for \Xa style overrides
function ass_alpha(a)
return string.format("&H%02X&", a)
end
-- Format an ABGR string for use in style definitions (these don't end with & either)
function ass_style_color(r,g,b,a)
return string.format("&H%02X%02X%02X%02X",a,b,g,r)
end
-- Extract colour components of an ASS colour
function extract_color(s)
local a, b, g, r
-- Try a style first
a, b, g, r = s:match("&H(%x%x)(%x%x)(%x%x)(%x%x)")
if a then
return, r, g, b, a
end
-- Then a colour override
b, g, r = s:match("&H(%x%x)(%x%x)(%x%x)&")
if b then
return, r, g, b, 0
end
-- Then an alpha override
a = s:match("&H(%x%x)&")
if a then
return 0, 0, 0, a
end
-- Ok how about HTML format then?
r, g, b, a = s:match("#(%x%x)(%x%x)?(%x%x)?(%x%x)?")
if r then
return r or 0, g or 0, b or 0, a or 0
end
-- Failed...
return nil
end
-- Create an alpha override code from a style definition colour code
function alpha_from_style(scolor)
local r, g, b, a = extract_color(scolor)
return ass_alpha(a)
end
-- Create an colour override code from a style definition colour code
function colour_from_style(scolor)
local r, g, b = extract_color(scolor)
return ass_color(r, g, b)
end
-- Converts HSV (Hue, Saturation, Value) to RGB
function HSV_to_RGB(H,S,V)
local r,g,b;
-- Saturation is zero, make grey
if S == 0 then
r = V*255
if r < 0 then
r = 0
end
if r > 255 then
r = 255
end
g = r
b = r
-- Else, calculate color
else
-- Calculate subvalues
local Hi = math.floor(H/60)
local f = H/60.0 - Hi
local p = V*(1-S)
local q = V*(1-f*S)
local t = V*(1-(1-f)*S)
-- Do math based on hue index
if Hi == 0 then
r = V*255.0
g = t*255.0
b = p*255.0
elseif Hi == 1 then
r = q*255.0
g = V*255.0
b = p*255.0
elseif Hi == 2 then
r = p*255.0
g = V*255.0
b = t*255.0
elseif Hi == 3 then
r = p*255.0
g = q*255.0
b = V*255.0
elseif Hi == 4 then
r = t*255.0
g = p*255.0
b = V*255.0
elseif Hi == 5 then
r = V*255.0
g = p*255.0
b = q*255.0
end
end
r = math.floor(r)
g = math.floor(g)
b = math.floor(b)
return r,g,b
end
-- Removes spaces at the start and end of string
function string.trim(s)
return (string.gsub(s, "^%s*(.-)%s*$", "%1"))
end
-- Get the "head" and "tail" of a string, treating it as a sequence of words separated by one or more space-characters
function string.headtail(s)
local a, b, head, tail = string.find(s, "(.-)%s+(.*)")
if a then
return head, tail
else
return s, ""
end
end
-- Iterator function for headtail
function string.words(s)
local t = s
local function wordloop()
if t == "" then
return nil
end
local head, tail = string.headtail(t)
t = tail
return head
end
return wordloop, nil, nil
end
-- Clamp a number value to a range
function clamp(val, min, max)
if val < min then
return min
elseif val > max then
return max
else
return val
end
end
-- Interpolate between two numbers
function interpolate(pct, min, max)
if pct <= 0 then
return min
elseif pct >= 1 then
return max
else
return pct * (max - min) + min
end
end
-- Interpolate between two colour values, given in either style definition or style override format
-- Return in style override format
function interpolate_color(pct, first, last)
local r1, g1, b1 = extract_color(first)
local r2, g2, b2 = extract_color(first)
local r, g, b = interpolate(pct, r1, r2), interpolate(pct, g1, g2), interpolate(pct, b1, b2)
return ass_color(r, g, b)
end
-- Interpolate between two alpha values, given either in style override or as part as a style definition colour
-- Return in style override format
function interpolate_alpha(pct, first, last)
local r1, g1, b1, a1 = extract_color(first)
local r2, g2, b2, a2 = extract_color(first)
return ass_alpha(interpolate(pct, a1, a2))
end