love2d virtual display for ascii graphics

--[=[
Example font image: https://vk.com/doc75175715_480892724
Charset for this image:
local charset = table.concat{
    [[ ☺☻♥♦♣♠•◘○◙♂♀♪♫☼]],
    [[►◄↕‼¶§▬↨↑↓→←∟↔▲▼]],
    [[ !"#$%&'()*+,-./]],
    [[0123456789:;<=>?]],
    [[@ABCDEFGHIJKLMNO]],
    [[PQRSTUVWXYZ[\]^_]],
    [[`abcdefghijklmno]],
    [[pqrstuvwxyz{|}~⌂]],
    [[ÇüéâäàåçêëèïîìÄÅ]],
    [[ÉæÆôöòûùÿÖÜ¢£¥₧ƒ]],
    [[áíóúñѪº¿⌐¬½¼¡«»]],
    [[░▒▓│┤╡╢╖╕╣║╗╝╜╛┐]],
    [[└┴┬├─┼╞╟╚╔╩╦╠═╬╧]],
    [[╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀]],
    [[αßΓπΣσµτΦΘΩδ∞φε∩]],
    [[≡±≥≤⌠⌡÷≈°∙·√ⁿ²■⯑]]
}

example for this img:


local d = display:new('image.png', 16, 16, charset)

]=]


local utf8  = require'utf8'
local display = {}
display._white = {1, 1, 1, 1}
display.__index = display

function display:new(image, w, h, sym, def)
    local gr   = love.graphics

    self       = setmetatable({}, self)
    self.map   = {}
    self.image = gr.newImage(image)
    self.layers  = {}
    self.layer = nil -- corrent layer

    self.image:setFilter('nearest')

    local iw, ih = self.image:getDimensions()
    self.w     = iw/w
    self.h     = ih/h

    local symw   = iw/self.w

    local i = 0
    for p, c in utf8.codes(sym) do
        local char = utf8.char(c)
        local x, y = i%symw, math.floor(i/symw)
        x, y = x * self.w, y * self.h
        local quad = gr.newQuad(x, y, self.w, self.h, iw, ih)
        self.map[char] = quad
        self.map[i]    = quad
        i = i + 1
    end

    self._s = assert(self:get(def or ' '))
    self._b = assert(self:get(def or ' '))

    self._scolor = self._white
    self._bcolor = self._white

    self:setLayer(1)
    return self
end

function display:get(sym)
    return self.map[sym]
end

function display:getImage()
    return self.image
end

function display:setLayer(i)
    local l = self.layers[i]
    if not l then
        l = {}
        l.batch = love.graphics.newSpriteBatch(self.image)
        l.used  = {}
        self.layers[i] = l
    end
    self.layer = l
end

function display:setColor(color, ...)
    if type(color) == 'table' then
        self._scolor = color
        return
    end
    if type(color) == 'number' then
        self._scolor = {color, ...}
        return
    end
    self._scolor = self._white
end

function display:setBackground(sym)
    self._b = assert(self:get(sym))
end

function display:setBackgroundColor(color, ...)
    if type(color) == 'table' then
        print('SET BCOLOR')
        self._bcolor = color
        return
    end
    if type(color) == 'number' then
        self._bcolor = {color, ...}
        return
    end
    self._bcolor = self._white
end

function display:draw(...)
    for i, v in pairs(self.layers) do
        love.graphics.draw(v.batch, ...)
    end
end

display.__call = display.get

function display:_batch_get(x, y)
    local layer = self.layer
    if not layer.used[y] then
        layer.used[y] = {}
    end
    if not layer.used[y][x] then
        -- background, tile
        layer.batch:setColor(self._bcolor)
        local sym  = layer.batch:add(self._b, x * self.w, y * self.h)
        layer.batch:setColor(self._scolor)
        local bcgr = layer.batch:add(self._s, x * self.w, y * self.h)
        layer.used[y][x] = {sym, bcgr}
    end

    return layer.used[y][x]
end

function display:_batch_set(quad, x, y, backgr, color)
    local layer = self.layer
    local tile = self:_batch_get(x, y)

    local index = backgr and tile[1] or tile[2]
    local color = color or backgr and self._bcolor or self._scolor

    layer.batch:setColor(color)
    layer.batch:set(index, quad, x * self.w, y * self.h)
end

function display:_clear_area(x, y, w, h, color)
    local layer = self.layer
    for i = x, x + w - 1 do
        for j = y, y + h - 1 do
            local tile = self:_batch_get(i, j)
            layer.batch:setColor(color or self._scolor)
            layer.batch:set(tile[1], self._b, i * self.w, j * self.h)
            layer.batch:setColor(color or self._bcolor)
            layer.batch:set(tile[2], self._s, i * self.w, j * self.h)
        end
    end
end

function display:print(str, px, py)
    assert(px, 'arg#1 x pos expected')
    assert(py, 'arg#2 y pos expected')

    local x, y = 0, 0
    local bit = 4
    for p, c in utf8.codes(str) do
        c = utf8.char(c)
        if c == '\n' then
            x = 0
            y = y + 1
        else
            local cx = (x + px)
            local cy = (y + py)
            local q  = self.map[c] or self.map[#self.map - 1]
            self:_batch_set(q, cx, cy)
            x = x + 1
        end
    end
end

function display:clearAll()
    for i, v in self.layers do
        v.batch:clear()
        v.used = {}
    end
end

function display:clearLayer(i)
    local l = self.layers[i] or self.layer
    if l then
        l.batch:clear()
        l.used = {}
    end
end

return display