Lanterna Demo

Lanterna.kt

import com.googlecode.lanterna.TerminalPosition
import com.googlecode.lanterna.TextColor
import com.googlecode.lanterna.input.KeyType
import com.googlecode.lanterna.screen.TerminalScreen
import com.googlecode.lanterna.terminal.DefaultTerminalFactory
import com.googlecode.lanterna.terminal.swing.AWTTerminalFontConfiguration.BoldMode
import com.googlecode.lanterna.terminal.swing.SwingTerminalFontConfiguration
import java.awt.Font
import java.nio.charset.Charset
import javax.swing.JFrame


fun main() {
    val fc = SwingTerminalFontConfiguration(true, BoldMode.EVERYTHING, Font("Source Code Pro", Font.PLAIN, 32))

    val screen = DefaultTerminalFactory(System.out, System.`in`, Charset.forName("UTF8"))
        .setTerminalEmulatorFontConfiguration(fc)
        .createSwingTerminal().apply {
            defaultCloseOperation = JFrame.EXIT_ON_CLOSE
            isVisible = true
            clearScreen()
        }.let { terminal ->
            TerminalScreen(terminal).apply { startScreen() }
        }

    var x = 0
    var y = 0
    var c: Char? = null

    var p1: TerminalPosition? = null
    var p2: TerminalPosition? = null

    while (true) {
        screen.doResizeIfNecessary()

        screen.newTextGraphics().apply {
            foregroundColor = TextColor.ANSI.RED
            backgroundColor = TextColor.ANSI.GREEN
            putString(0, 0, "($x, $y), p1: $p1 p2: $p2      ")
        }

        if (c != null) {
            screen.newTextGraphics().apply { putString(x, y, "$c") }
            if (c != ' ') x++
            c = null
        }

        if (p1 != null && p2 != null) {
            screen.newTextGraphics().apply {
                foregroundColor = TextColor.ANSI.RED
                drawLine(p1, p2, '*')
            }
            p1 = null
            p2 = null
        }

        screen.cursorPosition = TerminalPosition(x, y)
        screen.refresh()

        val input = screen.readInput()
        when (input.keyType) {
            KeyType.Escape -> break
            KeyType.Character -> {
                c = input.character
                if (c == ' ') {
                    c = null
                    TerminalPosition(x, y).let { p ->
                        if (p1 != null) {
                            p2 = p
                        } else {
                            p1 = p
                        }
                    }
                }
            }
            KeyType.ArrowUp -> if (y > 0) y--
            KeyType.ArrowDown -> if (y + 1 < screen.terminalSize.rows) y++
            KeyType.ArrowLeft -> if (x > 0) x--
            KeyType.ArrowRight -> if (x + 1 < screen.terminalSize.columns) x++
            KeyType.Backspace -> if (x > 0) {
                x--
                c = ' '
            }
        }
    }

    screen.stopScreen(true)
}