How can I add "proper" images (not Icons) to my JFrame/JPanel/JComponents (Swing) (Kotlin) - image

Question

Language: Kotlin,
GUI Library: Swing,
IDE: IntelliJ IDEA
I know that there are similarly phrased questions, but note that I want to add multiple images, not just one, to any type of JComponent that holds other components. For example, I am not concerned with adding an image to a JLabel, I already know how to do that. I want to know how to add an image to a JFrame, JPanel, Container, etc.; all things that hold other Components (and have an add(Component) function). Finally, I don't want that workaround where you add the image to a JLabel with no text and then add that to the container. I would like to just use the Image class or a subset like BufferedImage or URL.
I want to be able to call the add() method from the Container class, jFrame.add(component) for example, where component is some sort of image. I want this to result in an image being displayed on the screen.
The ImageIcon class is not a Component so this can't be input on its own. I think I would have to create some sort of custom Image class that extends from Component or JComponent, but I don't know what I would have to override to get that to display an image on screen when added to another JComponent. There are multiple solutions to this, but to clarify, I don't want some kind of "middle man" where I add a JLabel or JButton or something that only contains an Icon. I don't want to display icons anyway, I want to display full-sized images anywhere on the screen. I will provide a possible example of what I want the final result to look like.
class MyApp() {
fun init() {
var jFrame = JFrame()
jFrame.add(Image("filepath/image.png"))
//Some other JFrame boiler plate
jFrame.isVisible = true
}
}
fun main() {
MyApp().init()
}
The unclear part is the Image class, and whether that's a custom class that inherits JImage, or some already defined class or method I don't know about. I know about ImageIO and BufferedImage and ImageIcon, but none of them directly go into this method, as they don't inherit Component or JComponent.
EDIT:
I tried using Camickr's second solution, but it didn't work. I will post the code to see if a made a simple mistake.
import java.awt.Image as AWTImage
import java.awt.Image.*
//Including these imports as I used name alias so I had to say what it was from.
open class JImage(var point: Point = Point(0, 0), image: AWTImage): JComponent() {
var image: ImageIcon = ImageIcon(image)
override fun paintComponent(g: Graphics?) {
super.paint(g)
g?.drawImage(image.image, point.x.toInt(), point.y.toInt(), null)
}
}
class SplashScreen(image: JImage): Frame() {
init {
//jFrame.isUndecorated = true
jFrame.add(image)
}
}
class MyApp {
fun init() {
var jFrame = SplashScreen(JImage(image = ImageIO.read(Loader().getClassLoader().getResourceAsStream("resources/images/splashscreen/SplashScreen.png"))).getScaledInstance(Size(1000, 1000*3/5)))
jFrame.isVisible = true
}
}
fun main() {
MyApp().init()
}
FINAL EDIT:
Okay, so I did make a simple mistake when trying this solution. I overrode paintComponent() but then inside it, I called super.paint(). Additionally, I realized I didn't have to use the ImageIcon class, which I didn't want to do anyway. This is the Image class I have come up with.
open class JImage(var point: Point = Point(0, 0), var image: AWTImage): JComponent() {
fun getScaledInstance(size: Size, scalingMethods: ScalingMethods = ScalingMethods.DEFAULT): JImage {
val scale: Int = when(scalingMethods) {
ScalingMethods.DEFAULT -> SCALE_DEFAULT
ScalingMethods.FAST -> SCALE_FAST
ScalingMethods.AREA_AVERAGING -> SCALE_AREA_AVERAGING
ScalingMethods.REPLICATE -> SCALE_REPLICATE
ScalingMethods.SMOOTH -> SCALE_SMOOTH
}
return JImage(point, image.getScaledInstance(size.width.toInt(), size.height.toInt(), scale))
}
override fun paintComponent(g: Graphics?) {
super.paintComponent(g)
g?.drawImage(image, point.x.toInt(), point.y.toInt(), null)
}
}

Answer 1

I want to know how to add an image to a JFrame, JPanel, Container, etc.
You don't add an image to a JFrame, JPanel etc. As you said an image is not a component. You add the image to a JLabel and add the label to the panel. This is the easiest and more direct way to display an image at its actual size.
Don't know if Kotlin is any different, but the other option is to do custom painting and paint the image on a JPanel by overriding the paintComponent(…) method and using the Graphics.drawImage(…) method and then add the panel to the frame. Read the Swing tutorial on Custom Painting for painting basics.
You can also check out Background Panel for an example that paints an image as a background of the panel. The image can be:
painted at its real size
scaled to fill the panel
tiled to fill the panel
Just note that the image should NOT be read in the paintComponent() method as painting code should be efficient.