1 Reply Latest reply: Jan 6, 2013 9:04 PM by darrylburke RSS

    pixels and RGB values of a .png file


      i started learning java last night and am trying to understand the java tutorials from docs.oracle
      at the moment i am doing an exercise where i should load a .png file, which originally is dark, and edit some of the RGB values, in a way that i could clearly see the hidden image.

      i think i am doing alright when it comes to loading an image and showing it, but i am failing at the process of reading the pixels and getting the RGB values.
      that is what i have, so far:
          public class ImagePuzzle {  
              public void solveBlackPuzzle() {  
              Picture input = new Picture(FileChooser.pickAFile());  
              Picture output = null;  
              if (input != null) {  
                   //  here i would grab the pixels, read their RGB values and change them.
                  String directory = "/home/user/";    
                  output.write(directory + "black-puzzle-solution.png");  
      this is what i think would be in the commented part:
          method to decrease red 
          get the pixels;  
          define an integer that will work as a counter  
          for (int= 0; i < my pixels number; i++)  
          p = pixels; 
      value = p.getRed();

      now it should show the picture, with the red value changed...


      when i manage to get the syntax correct, the code is compiled and it shows the open directory dialog, i choose an image, it shows me the image and nothing more happens.
      otherwise i cant manage to have the correct syntax.
      i understand my structure as
      public Class 
      public void solveBlackPuzzle
      does it make sense to include the method i want inside public void solveBlackPuzzle? I have a class called Pixel, Picture and FileChooser.
      If i try to create my Pixel object inside this part of the code, it tells me i am doing something illegal.
      thanks in advance and kind regards.