How do you display images on the screen using java?

Answer 1

Java Swings has a lot of nice features and one of them is the ability to display images on its components. You can select any image that is available in the local system or somewhere on the internet and display it on Graphics objects. As of Java SE 1.4, reading an image is very simple.

If the image is stored in a local file:

String filename = "...";

Image image = ImageIO.read(new File(filename));

Otherwise, you can supply a URL:

String urlname = "...";

Image image = ImageIO.read(new URL(urlname));

The read method throws an IOException if the image is not available.

Now the variable image contains a reference to an object that encapsulates the image data. You can display the image with the drawImage method of the Graphics class.

public void paintComponent(Graphics g)

{

. . .

g.drawImage(image, x, y, null);

}

Sometimes, you may want to tile an image across a components canvas if it is much smaller than the component size. We can do the tiling in the paintComponent method. We first draw one copy of the image in the top-left corner and then use the copyArea call to copy it into the entire window using the code below:

for (int i = 0; i * imageWidth <= getWidth(); i++) for (int j = 0; j * imageHeight <= getHeight(); j++) if (i + j > 0)

g.copyArea(0, 0, imageWidth, imageHeight, i * imageWidth, j * imageHeight);