Syntax Error using Graphics

Question

I am using the below code to merge two PNGs together although I get a syntax error on both the lines which start with g.drawImage. This is coming from an example at Merging two images but I can not comment on it because I just signed up here.

package imageEditor;

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;

public class ImageEditor15092703 {
    File path = new File("C:/Users/Colton/Desktop/JavaImageEditor/"); // base path of the images

    // load source images
    BufferedImage image = ImageIO.read(new File(path, "image.png"));
    BufferedImage overlay = ImageIO.read(new File(path, "overlay.png"));

    // create the new image, canvas size is the max. of both image sizes
    int w = Math.max(image.getWidth(), overlay.getWidth());
    int h = Math.max(image.getHeight(), overlay.getHeight());
    BufferedImage combined = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);

    // paint both images, preserving the alpha channels
    Graphics g = combined.getGraphics();
    g.drawImage(image, 0, 0, null);
    g.drawImage(overlay, 0, 0, null);

    // Save as new image
    ImageIO.write(combined, "PNG", new File(path, "combined.png"));
}

Thanks

EDIT

I got further with the help so far by making a method and exceptions. It now compiles and runs although it does not create the new png file. I feel like there are exceptions thrown which stops the program from doing what it should.

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class ImageEditor15092705{

    public void ImageEditor15092705() throws IOException{
        File path = new File("C:/Users/Colton/Desktop/JavaImageEditor/"); // base path of the images

        // load source images
        BufferedImage image = ImageIO.read(new File(path, "image.png"));
        BufferedImage overlay = ImageIO.read(new File(path, "overlay.png"));

        // create the new image, canvas size is the max. of both image sizes
        int w = Math.max(image.getWidth(), overlay.getWidth());
        int h = Math.max(image.getHeight(), overlay.getHeight());
        BufferedImage combined = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);

        // paint both images, preserving the alpha channels
        Graphics g = combined.getGraphics();
        g.drawImage(image, 0, 0, null);
        g.drawImage(overlay, 0, 0, null);

        // Save as new image
        ImageIO.write(combined, "PNG", new File(path, "combined.png"));
    }

    public static void main (String[] args)
   {
   ImageEditor15092705 foo = new ImageEditor15092705();
   }//end main

} //end image editor class

Answer 1

You have this error because you should write statements in a method, not a class. You see, you created a class, and you write statements immediately in the class. You should write the statements in a method and some statements throw an exception so you should add throw IOException, like this;

public static void mergeImage (String p_basePath, String p_image, String p_overlay) throws IOException {
    File path = new File(p_basePath); // base path of the images

    // load source images
    BufferedImage image = ImageIO.read(new File(path, p_image));
    BufferedImage overlay = ImageIO.read(new File(path, p_overlay));

    // create the new image, canvas size is the max. of both image sizes
    int w = Math.max(image.getWidth(), overlay.getWidth());
    int h = Math.max(image.getHeight(), overlay.getHeight());
    BufferedImage combined = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);

    // paint both images, preserving the alpha channels
    Graphics g = combined.getGraphics();
    g.drawImage(image, 0, 0, null);
    g.drawImage(overlay, 0, 0, null);

    // Save as new image
    ImageIO.write(combined, "PNG", new File(path, "combined.png"));
}

Alternatively you can add parameters:

public static void mergeImage () throws IOException {
    File path = new File("C:/Users/Colton/Desktop/JavaImageEditor/"); // base path of the images

    // load source images
    BufferedImage image = ImageIO.read(new File(path, "image.png"));
    BufferedImage overlay = ImageIO.read(new File(path, "overlay.png"));

    // create the new image, canvas size is the max. of both image sizes
    int w = Math.max(image.getWidth(), overlay.getWidth());
    int h = Math.max(image.getHeight(), overlay.getHeight());
    BufferedImage combined = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);

    // paint both images, preserving the alpha channels
    Graphics g = combined.getGraphics();
    g.drawImage(image, 0, 0, null);
    g.drawImage(overlay, 0, 0, null);

    // Save as new image
    ImageIO.write(combined, "PNG", new File(path, "combined.png"));
}

Next time, just remember, always write statements in methods or constructors and be aware of the possible exceptions that some methods will throw.

Answer 2

The code syntax looks totally fine I don't understand why it's giving you errors, what is exactly the error that you get? P.S: I'll run the code on my pc and I'll follow up soon with an edit

EDIT: Ok so there were 2 problems,

1. The code wasn't in a constructor/function so this confused the IDE (I added a constructor in the example but you should place the code in a function for better practice)
2. There were some unhandled IOExceptions there, you con fix it in two ways, the one is to make the constructor (or function) throw an IOException or alternatively surround the ImageIO.write() and ImageIO.read() functions with a try/catch block

here is what works for me: package imageEditor;

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class ImageEditor15092703{

    public ImageEditor15092703() throws IOException{
        File path = new File("C:/Users/Colton/Desktop/JavaImageEditor/"); // base path of the images

        // load source images
        BufferedImage image = ImageIO.read(new File(path, "image.png"));
        BufferedImage overlay = ImageIO.read(new File(path, "overlay.png"));

        // create the new image, canvas size is the max. of both image sizes
        int w = Math.max(image.getWidth(), overlay.getWidth());
        int h = Math.max(image.getHeight(), overlay.getHeight());
        BufferedImage combined = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);

        // paint both images, preserving the alpha channels
        Graphics g = combined.getGraphics();
        g.drawImage(image, 0, 0, null);
        g.drawImage(overlay, 0, 0, null);

        // Save as new image
        ImageIO.write(combined, "PNG", new File(path, "combined.png"));
    }

} 

as I said this code code should work but is NOT better practice use the alternatives that I suggested above