I have been working on a small problem of changing the values of pixels to "red" (or any color other than black or white).

I modify the pixel itself and its six neighbors. As per the changes the pixel values must be changed to "red". But when I run another loop over the image to verify the changes, out of 7 pixels only 3 or sometimes 4 come up as red. Upon further analysis I found out that the pixel values are some shade of red.

How can I make sure that when I set the value of the pixel it is color(255,0,0) and not a shade?

Ciao!

2. img1.loadPixels();
3. int loc = pixelX + pixelY*img2.width;
4. img1.pixels[loc] = color(255,0,0);
5. 
   
6. loc = pixelX + (pixelY +1)*img2.width;
7. img1.pixels[loc] = color(255,0,0);
9. loc = (pixelX+1) + (pixelY+1)*img2.width;
10. img1.pixels[loc] = color(255,0,0);
11. 
    
12. loc = pixelX + (pixelY-1)*img2.width;
13. img1.pixels[loc] = color(255,0,0);
14. 
    
15. loc = (pixelX+1) + (pixelY-1)*img2.width;
16. img1.pixels[loc] = color(255,0,0);
17. 
    
18. loc = (pixelX+1) + (pixelY)*img2.width;
19. img1.pixels[loc] = color(255,0,0);
20. 
    
21. loc = (pixelX-1) + (pixelY)*img2.width;
22. img1.pixels[loc] = color(255,0,0);
23. 
    
24. img1.updatePixels();
25. img1.save("modifiedImage.jpg");
26. 
    
27. img1.loadpixels();
28. 
    
29. for (int i=2; i < img1.width; i++)
30. {
31. for (int j=2; j < img1.height; j++) 
32. {
33. loc = i + (2*j)*img1.width;
34. if (img1.pixels[i + (2*j)*img1.width] == color(255,0,0))
35. {
36. println("Pixels " + i + ":" +2*j);
37. }
38. }
39. }