A quick way of displaying pixels (with optional animation) in a JFrame

Piskie.kt

import java.awt.Color.BLACK
import java.awt.Dimension
import java.awt.Graphics
import java.awt.Toolkit
import java.awt.image.BufferedImage
import java.awt.image.BufferedImage.TYPE_INT_ARGB
import java.awt.image.BufferedImage.TYPE_INT_RGB
import javax.swing.JFrame
import javax.swing.JPanel
import kotlin.Int.Companion.MAX_VALUE
import kotlin.random.Random.Default.nextInt



/**
 * A quick way of displaying pixels (with optional animation) in a JFrame
 */
class PFrame(image: BufferedImage, tit: String = "") : JFrame() {

    private val panel: PPanel = PPanel(image)

    init {
        add(panel)
        pack()
        setLocationRelativeTo(null)

        isResizable = false
        title = tit
        defaultCloseOperation = EXIT_ON_CLOSE
        isVisible = true
    }

    fun render() = panel.repaint()



    private class PPanel(val image: BufferedImage) : JPanel() {
        init {
            background = BLACK
            preferredSize = Dimension(image.width, image.height)
        }

        public override fun paintComponent(g: Graphics) {
            super.paintComponent(g)

            g.drawImage(image, 0, 0, this)
            Toolkit.getDefaultToolkit().sync()
        }
    }
}

fun randomPixels(imageType: Int =  TYPE_INT_ARGB) {
    val size = 350
    val image = BufferedImage(size, size, imageType)
    val frame = PFrame(image)

    for (i in 0..1000000) {
        image.setRGB(nextInt(size), nextInt(size), nextInt())

        if (i.rem(10000) == 0) {
            frame.render()
            Thread.sleep(100)
        }
    }
    frame.render()
}

fun squares() {
    val size = 400
    val sqSize = size / 10

    val image = BufferedImage(size, size, TYPE_INT_RGB)
    val frame = PFrame(image)

    for (i in 0 until size) {
        for (j in 0 until size) {
            val x = (i / sqSize).rem(2)
            val y = (j / sqSize).rem(2)

            if (x + y == 0 || x + y == 2) {
                image.setRGB(i, j, MAX_VALUE)
            }
        }
    }
    frame.render()
}



fun main() {
    randomPixels()
}