Typewriter

local natiny = require("natiny")

natiny.backend.init()

local win = natiny.window.create("Typewriter", 900, 600)
natiny.window.set_scale_mode(win, natiny.window.SCALE_MODE_STRETCH)

local res  = natiny.resource.load("common/fonts/roboto.ttf")
local font = natiny.font.create(res, 26)
local small = natiny.font.create(res, 18)

local MESSAGE = "Missing glyphs are baked when first drawn. preload does this during " ..
                "loading, so the pause stays hidden."

natiny.font.preload(font, MESSAGE)
natiny.font.set_line_spacing(font, 1.15)

local BG = natiny.color.from_hex("#151E2C")
local OBJECT = natiny.color.from_hex("#A9B3C5")
local ACCENT = natiny.color.from_hex("#F8F9FD")
local LIGHT_TEXT = natiny.color.from_hex("#F3F5FA")
local DARK_TEXT = natiny.color.from_hex("#111827")
local X, Y, W = 120, 140, 660
local TOTAL = utf8.len(MESSAGE)
local shown, blink = 0, 0

natiny.backend.loop(function(dt)
    natiny.window.bind(win, function()
        shown = math.min(TOTAL, shown + dt * 26)
        blink = blink + dt

        local cut = utf8.offset(MESSAGE, math.floor(shown) + 1) or (#MESSAGE + 1)
        local visible = MESSAGE:sub(1, cut - 1)
        local caret = (blink % 1.0 < 0.55) and "_" or " "

        local _, full_h = natiny.font.measure_wrapped(font, MESSAGE, W)

        natiny.render.clear(BG)

        natiny.render.set_color(OBJECT)
        natiny.render.rectangle(X - 24, Y - 24, W + 48, full_h + 48)

        natiny.render.set_color(DARK_TEXT)
        natiny.render.text_box(font, X, Y, W, full_h, visible .. caret)

        natiny.render.set_color(OBJECT)
        natiny.render.rectangle(X, Y + full_h + 44, W, 4)
        natiny.render.set_color(ACCENT)
        natiny.render.rectangle(X, Y + full_h + 44, W * shown / TOTAL, 4)

        natiny.render.set_color(LIGHT_TEXT)
        natiny.render.text(small, X, Y + full_h + 60,
               string.format("%d / %d code points", math.floor(shown), TOTAL))
    end)
end)

natiny.backend.shutdown()