--[[ Copyright (c) 2012 Matthias Richter Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. Except as contained in this notice, the name(s) of the above copyright holders shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ]]-- local stack = {n = 0} local default = { pos = {0,0}, grow = {0,0}, spacing = 2, size = {100, 30}, upper_left = {0,0}, lower_right = {0,0}, } local current = default local Grow = { none = { 0, 0}, up = { 0, -1}, down = { 0, 1}, left = {-1, 0}, right = { 1, 0} } -- {grow = grow, spacing = spacing, size = size, pos = pos} local function push(info) local grow = info.grow or "none" local spacing = info.spacing or default.spacing local size = { info.size and info.size[1] or current.size[1], info.size and info.size[2] or current.size[2] } local pos = {current.pos[1], current.pos[2]} if info.pos then pos[1] = pos[1] + (info.pos[1] or 0) pos[2] = pos[2] + (info.pos[2] or 0) end assert(size, "Size neither specified nor derivable from parent group.") assert(pos, "Position neither specified nor derivable from parent group.") grow = assert(Grow[grow], "Invalid grow: " .. tostring(grow)) current = { pos = pos, grow = grow, size = size, spacing = spacing, upper_left = { math.huge, math.huge}, lower_right = {-math.huge, -math.huge}, } stack.n = stack.n + 1 stack[stack.n] = current end local function advance(pos, size) current.upper_left[1] = math.min(current.upper_left[1], pos[1]) current.upper_left[2] = math.min(current.upper_left[2], pos[2]) current.lower_right[1] = math.max(current.lower_right[1], pos[1] + size[1]) current.lower_right[2] = math.max(current.lower_right[2], pos[2] + size[2]) if current.grow[1] ~= 0 then current.pos[1] = pos[1] + current.grow[1] * (size[1] + current.spacing) end if current.grow[2] ~= 0 then current.pos[2] = pos[2] + current.grow[2] * (size[2] + current.spacing) end return pos, size end local function getRect(pos, size) pos = {pos and pos[1] or 0, pos and pos[2] or 0} size = {size and size[1] or current.size[1], size and size[2] or current.size[2]} -- growing left/up: update current position to account for differnt size if current.grow[1] < 0 and current.size[1] ~= size[1] then current.pos[1] = current.pos[1] + (current.size[1] - size[1]) end if current.grow[2] < 0 and current.size[2] ~= size[2] then current.pos[2] = current.pos[2] - (current.size[2] - size[2]) end pos[1] = pos[1] + current.pos[1] pos[2] = pos[2] + current.pos[2] return advance(pos, size) end local function pop() assert(stack.n > 0, "Group stack is empty.") stack.n = stack.n - 1 local child = current current = stack[stack.n] or default local size = { child.lower_right[1] - math.max(child.upper_left[1], current.pos[1]), child.lower_right[2] - math.max(child.upper_left[2], current.pos[2]) } advance(current.pos, size) end local function beginFrame() current = default stack.n = 0 end local function endFrame() -- future use? end return setmetatable({ push = push, pop = pop, getRect = getRect, advance = advance, beginFrame = beginFrame, endFrame = endFrame, default = default, }, { __index = function(_,k) return ({size = current.size, pos = current.pos})[k] end, __call = function(_, info) assert(type(info) == 'table' and type(info[1]) == 'function') push(info) info[1]() pop() end, })