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--[[ Lua Floodfill function
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2017 William Wilgus
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
]]
-- floods an area of targetclr with fillclr x, y specifies the start seed
-- flood_fill(img, x, y, targetclr, fillclr)
if not rb.lcd_framebuffer then rb.splash(rb.HZ, "No Support!") return nil end
do
local rocklib_image = getmetatable(rb.lcd_framebuffer())
local _NIL = nil -- nil placeholder
local _get = rocklib_image.get
local _line = rocklib_image.line
local _marshal = rocklib_image.marshal
return function(img, x, y, targetclr, fillclr)
-- scanline 4-way flood algorithm
-- ^
-- <--------x--->
-- v
-- check that target color doesn't = fill and the first point is target color
if targetclr == fillclr or targetclr ~= _get(img, x, y, true) then return end
local max_w = img:width()
local max_h = img:height()
local qpt = {} -- FIFO queue
-- rather than moving elements around in our FIFO queue
-- for each read; increment 'qhead' by 2
-- set both elements to nil and let the
-- garbage collector worry about it
-- for each write; increment 'qtail' by 2
-- x coordinates are in odd indices while
-- y coordinates are in even indices
local qtail = 0
local function check_ns(val, x, y)
if targetclr == val then
y = y - 1
if targetclr == _get(img, x, y, true) then -- north
qtail = qtail + 2
qpt[qtail - 1] = x
qpt[qtail] = y
end
y = y + 2
if targetclr == _get(img, x, y, true) then -- south
qtail = qtail + 2
qpt[qtail - 1] = x
qpt[qtail] = y
end
return fillclr
end
return _NIL -- signal marshal to stop
end
local function seed_pt(x, y)
-- should never hit max but make sure not to end early
for qhead = 2, 0x40000000, 2 do
if targetclr == _get(img, x, y, true) then
_marshal(img, x, y, 1, y, _NIL, _NIL, true, check_ns) -- west
_marshal(img, x + 1, y, max_w, y, _NIL, _NIL, true, check_ns) -- east
end
x = qpt[qhead - 1]
qpt[qhead - 1] = _NIL
if not x then break end
y = qpt[qhead]
qpt[qhead] = _NIL
end
end
seed_pt(x, y) -- Begin
end -- flood_fill
end
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