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/**
* @author Pacien TRAN-GIRARD
* @author Timothée FLOURE
*/
public final class Color {
public static final int BYTE_MASK = 0b11111111;
public static final float DECIMAL_NORMALIZER = 255.0f;
public static final int RED_SHIFT = 16;
public static final int GREEN_SHIFT = 8;
public static final int BLUE_SHIFT = 0;
/**
* Returns shifted component from given packed color.
*
* @param rgb 32-bits RGB color
* @param shift binary shift
* @return a float between 0.0 and 1.0
* @see #getRGBValue
*/
private static float getNormalizedRGBComponent(int rgb, int shift) {
return ((float) (rgb >> shift & BYTE_MASK)) / DECIMAL_NORMALIZER;
}
/**
* Returns RGB binary value from given component and color shift.
*
* @param component a float between 0.0 and 1.0
* @param shift binary shift
* @return 32-bits RGB color
* @see #getNormalizedRGBComponent
*/
private static int getRGBValue(float component, int shift) {
if (component < 0.0f) component = 0.0f;
if (component > 1.0f) component = 1.0f;
return ((int) (component * DECIMAL_NORMALIZER) & BYTE_MASK) << shift;
}
/**
* Returns red component from given packed color.
*
* @param rgb 32-bits RGB color
* @return a float between 0.0 and 1.0
* @see #getGreen
* @see #getBlue
* @see #getRGB(float, float, float)
*/
public static float getRed(int rgb) {
return Color.getNormalizedRGBComponent(rgb, RED_SHIFT);
}
/**
* Returns green component from given packed color.
*
* @param rgb 32-bits RGB color
* @return a float between 0.0 and 1.0
* @see #getRed
* @see #getBlue
* @see #getRGB(float, float, float)
*/
public static float getGreen(int rgb) {
return Color.getNormalizedRGBComponent(rgb, GREEN_SHIFT);
}
/**
* Returns blue component from given packed color.
*
* @param rgb 32-bits RGB color
* @return a float between 0.0 and 1.0
* @see #getRed
* @see #getGreen
* @see #getRGB(float, float, float)
*/
public static float getBlue(int rgb) {
return Color.getNormalizedRGBComponent(rgb, BLUE_SHIFT);
}
/**
* Returns the average of red, green and blue components from given packed color.
*
* @param rgb 32-bits RGB color
* @return a float between 0.0 and 1.0
* @see #getRed
* @see #getGreen
* @see #getBlue
* @see #getRGB(float)
*/
public static float getGray(int rgb) {
return (Color.getRed(rgb) + Color.getGreen(rgb) + Color.getBlue(rgb)) / 3.0f;
}
/**
* Returns packed RGB components from given red, green and blue components.
*
* @param red a float between 0.0 and 1.0
* @param green a float between 0.0 and 1.0
* @param blue a float between 0.0 and 1.0
* @return 32-bits RGB color
* @see #getRed
* @see #getGreen
* @see #getBlue
*/
public static int getRGB(float red, float green, float blue) {
int rgbValue = 0b0;
rgbValue |= Color.getRGBValue(red, RED_SHIFT);
rgbValue |= Color.getRGBValue(green, GREEN_SHIFT);
rgbValue |= Color.getRGBValue(blue, BLUE_SHIFT);
return rgbValue;
}
/**
* Returns packed RGB components from given grayscale value.
*
* @param gray a float between 0.0 and 1.0
* @return 32-bits RGB color
* @see #getGray
*/
public static int getRGB(float gray) {
return Color.getRGB(gray, gray, gray);
}
/**
* Converts packed RGB image to grayscale float image.
*
* @param image a HxW int array
* @return a HxW float array
* @see #toRGB
* @see #getGray
*/
public static float[][] toGray(int[][] image) {
int width = image[0].length;
int height = image.length;
float[][] floatImage = new float[height][width];
for (int row = 0; row < height; ++row)
for (int col = 0; col < width; ++col)
floatImage[row][col] = Color.getGray(image[row][col]);
return floatImage;
}
/**
* Converts grayscale float image to packed RGB image.
*
* @param gray a HxW float array
* @return a HxW int array
* @see #toGray
* @see #getRGB(float)
*/
public static int[][] toRGB(float[][] gray) {
int width = gray[0].length;
int height = gray.length;
int[][] rgbImage = new int[height][width];
for (int row = 0; row < height; ++row)
for (int col = 0; col < width; ++col)
rgbImage[row][col] = Color.getRGB(gray[row][col]);
return rgbImage;
}
}
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