/**
* Hides the given message inside the specified image.
*
* <p>The image will be given to you as a GImage of some size, and the message will be specified
* as a boolean array of pixels, where each white pixel is denoted false and each black pixel is
* denoted true.
*
* <p>The message should be hidden in the image by adjusting the red channel of all the pixels in
* the original image. For each pixel in the original image, you should make the red channel an
* even number if the message color is white at that position, and odd otherwise.
*
* <p>You can assume that the dimensions of the message and the image are the same.
*
* <p>
*
* @param message The message to hide.
* @param source The source image.
* @return A GImage whose pixels have the message hidden within it.
*/
public static GImage hideMessage(boolean[][] message, GImage source) {
int[][] pixels = source.getPixelArray();
for (int row = 0; row < pixels.length; row++) {
for (int col = 0; col < pixels[row].length; col++) {
/* Extract the green and blue components and write them back, changing the
* red component.
*/
int red = GImage.getRed(pixels[row][col]);
int green = GImage.getGreen(pixels[row][col]);
int blue = GImage.getBlue(pixels[row][col]);
if (message[row][col]) {
if (red % 2 == 0) { // If the secret pixel is black, make the red channel odd
red++;
}
} else {
if (red % 2 != 0) { // If the secret pixel is white, make the red channel even
red++;
}
if (red > 255) {
red -= 2;
}
}
pixels[row][col] = GImage.createRGBPixel(red, green, blue);
}
}
return new GImage(pixels);
}
private static int redToEven(int pixel) { // в НЕЧЕТНЫЙ
int oldRed = GImage.getRed(pixel);
int newRed;
if (oldRed % 2 == 1) { // нечетный
newRed = oldRed;
} else { // если четный
newRed = oldRed + 1;
}
return GImage.createRGBPixel(
newRed, GImage.getGreen(pixel), GImage.getBlue(pixel), GImage.getAlpha(pixel));
}
public static GImage toGrayscale(GImage image) {
int[][] pixels = image.getPixelArray();
for (int row = 0; row < pixels.length; ++row) {
for (int col = 0; col < pixels[row].length; ++col) {
int intensity =
(int)
(0.3D * (double) GImage.getRed(pixels[row][col])
+ 0.59D * (double) GImage.getGreen(pixels[row][col])
+ 0.11D * (double) GImage.getBlue(pixels[row][col])
+ 0.5D);
pixels[row][col] = GImage.createRGBPixel(intensity, intensity, intensity);
}
}
return new GImage(pixels);
}
