Suggestions on colour convertor program

[Mikpo Siru]

Hi,

I want to write a program that maps the colours of a user-selected image to the closest matching colours in a given set. Here is the basic operation:

-User opens an image using the program
-The program checks the colour of each pixel in the image
-For each pixel, the program chooses the closest matching colour from a set of eight colours (red, green, blue, cyan, magenta, yellow, white, black)
-The program makes a new image from the 8 colours
-The program displays the new image

I have GUI programming experience in Java, but it's been some months since my last project (this is abit of a refresher).

I am looking for is suggestions on how to proceed. For example, useful classes, good methods of implementation (should I go through pixel by pixel?), etc.

Thanks

[Darryl Burke]

Take the easy way ;)

-- Load your image
-- Create a IndexColorModel with the required colors
-- Construct a BufferedImage the same size as your image, of TYPE_BYTE_INDEXED and the index color model
-- Obtain the Graphics reference of the second image
-- Draw the first image to the second image
-- Profit

[Mikpo Siru]

Hi,

Thanks for the reply. I have started a sister thread specifically on making an IndexColorModel: https://coderanch.com/t/504292/GUI/java/Creating-IndexColorModel-Colours.

I will post problems I have with the overall convterter program in this thread.

Regards.

[Mikpo Siru]

Thanks Darryl, I have a working program now.

For reference, here is the part of the program that does the conversion:

   
Image loadedImage;    //user selected image
Image convertedImage;    //converted version of selected image
...
...
 //Converts the user selected image
    void convertSelectedImage() {
        //make sure an image is loaded
        if(loadedImage == null)
            return;
        
        convertedImage = new BufferedImage(
                loadedImage.getWidth(null), loadedImage.getHeight(null),
                BufferedImage.TYPE_BYTE_INDEXED, colourModel);

        convertedImage.getGraphics().drawImage(loadedImage, 0, 0, null);
    }

IndexColorModel colourModel was generated using Darryl's code snippet in https://coderanch.com/t/504292/GUI/java/Creating-IndexColorModel-Colours:

 Color[] colors = {Color.red, Color.green, Color.blue,  
     Color.cyan, Color.magenta, Color.yellow,  
     Color.white, Color.black};  
     byte[] reds = new byte[8];  
     byte[] greens = new byte[8];  
     byte[] blues = new byte[8];  
     for (int i = 0; i < colors.length; i++) {  
       reds[i] = (byte) colors[i].getRed();  
       greens[i] = (byte) colors[i].getGreen();  
       blues[i] = (byte) colors[i].getBlue();  
     } 

Regards.