scanning an image for a certain pixel color in java

[me erum]

I'm working on a project and quiet new to java. I want to scan an image pixel by pixel for a certain color, i.e. cyan and then print the coordinates of that pixel color. The code runs, creates an output file but doesn't write anything to it. Can somebody please help me with it to find the errors. I also want to know how to read a .tiff file in java while using the same code.

Java Code:

import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.*;
import javax.imageio.ImageIO;

public class GetPixel {

    //int y, x, tofind, col;

    /**
     * @param args the command line arguments
     * @throws IOException  
     */

    public static void main(String args[]) throws IOException {
        
            //read image file
            File file1 = new File("E:\\dp.jpg");    
            BufferedImage image1 = ImageIO.read(file1);

            //write file
            FileWriter fstream = new FileWriter("E:\\pixellog.txt");
            BufferedWriter out = new BufferedWriter(fstream);

            //color object
            //Color cyan = new Color(0, 255, 255);

            //find cyan pixels
            for (int y = 0; y < image1.getHeight(); y++) {
                for (int x = 0; x < image1.getWidth(); x++) {
                    
                    int c = image1.getRGB(x,y);
                     
                    int  red = (c & 0x0000FFFF) >> 16;
                    int  green = (c & 0x0000FFFF) >> 8;
                    int  blue = c & 0x0000FFFF;
                    
                    //  int tofind = 0x0000FFFF;

                    //int tofind = Color.cyan.getRGB();

                    //int  col = image1.getRGB(x, y);

                    //if (col == tofind){

                    //if (cyan.equals(image1.getRGB(x, y)){
                    //if (Color.cyan.getRGB() == image1.getRGB(x, y)) {
                        
                     
                    
                     if (red < 30 && green > 255 && blue > 255) {   
                        out.write("CyanPixel found at=" + x + "," + y);
                        
                     
                    }
                }
            }
        
    }
}

[Jesper de Jong]

Welcome to the Ranch.

These masks look wrong:

int red = (c & 0x0000FFFF) >> 16;
int green = (c & 0x0000FFFF) >> 8;
int blue = c & 0x0000FFFF;

Red is in bits 16-23; green is in bits 8-15; blue is in bits 0-7. It should be:

int red = (c & 0x00FF0000) >> 16;
int green = (c & 0x0000FF00) >> 8;
int blue = c & 0x000000FF;

Also, you should call close() on out at the end of the program.

[Darryl Burke]

if (red < 30 && green > 255 && blue > 255) {

When is a r/g/b component ever greater than 255?

[Campbell Ritchie]

Darryl Burke wrote:

if (red < 30 && green > 255 && blue > 255) {

When is a r/g/b component ever greater than 255?

When I try to explain to our undergraduates that new Color(0, 0xff00, 0) if it ever gets past the runtime will not set the colour to a brighter green than normal, but to red.

By the way: I think you ought not to use 255. I prefer to use 0xff. These numbers are demoninated in hex, so I think they ought to be assessed in hex.

[Randall Twede]

for reading .tiff files try ImageIO class.

[Jesper de Jong]

Randall Twede wrote:for reading .tiff files try ImageIO class.

He's already using the ImageIO class (to read a JPG image, in his code above). Unfortunately the JDK doesn't come with support for the TIFF format (the only formats that ImageIO can read without extra plug-ins are: JPG PNG BMP WBMP GIF) - see the API docs for the package javax.imageio.