Develop Reference

Cannot find symbol - method setColor(java.awt.Color)?

I am attempting to create a new color palette for an image turned to gray scale, and then apply the palette to the gray scale image. I began the method that I wanted to use to apply the palette, but I ran into the error mentioned in the title. I used "java.awt.Color" already in my code, so I am not sure why I am getting the error. Also, as you will see, I placed a color inside the parenthesis.
/**
* This program takes an image, converts it to grayscale, and uses a color palette to create new colors for the image.
*
* #author Dylan Hubbs
* #version 08/02/16
*/
import java.awt.Color ;
class ColorPalette
{
public void grayscaleEffect(Picture pictureObj)
{
int redValue = 0; int greenValue = 0; int blueValue = 0;
Pixel grayscaleTargetPixel = new Pixel(pictureObj, 0,0);
Color grayscalePixelColor = null;
for(int y=0; y < pictureObj.getHeight(); y++)
{
for(int x = 0; x < pictureObj.getWidth(); x++)
{
grayscaleTargetPixel = pictureObj.getPixel(x,y);
grayscalePixelColor = grayscaleTargetPixel.getColor(); //gets the color of the target pixel
grayscalePixelColor = new Color((grayscaleTargetPixel.getRed() + grayscaleTargetPixel.getGreen() + grayscaleTargetPixel.getBlue()) / 3, (grayscaleTargetPixel.getRed() + grayscaleTargetPixel.getGreen() + grayscaleTargetPixel.getBlue()) / 3, (grayscaleTargetPixel.getRed() + grayscaleTargetPixel.getGreen() + grayscaleTargetPixel.getBlue()) / 3);
grayscaleTargetPixel.setColor(grayscalePixelColor); //sets the new color of the target pixel
}//end of the inner for loop
}//end of the outer for loop
pictureObj.explore(); //explore the Picture object which is now the altered image
pictureObj.write("grayscaleWashingtonMonument.jpg"); //write the altered Picture object to a new file
pictureObj.show();
}
public void paletteEffect(Picture pictureObj)
{
int redValue = 0; int greenValue = 0; int blueValue = 0;
Pixel paletteTargetPixel = new Pixel(pictureObj, 0,0);
Color palettePixelColor = null;
Color [] palette = {Color.RED, Color.BLUE, Color.CYAN, Color.GREEN, Color.YELLOW, Color.GRAY, Color.PINK, Color.ORANGE};
for(int y=0; y < pictureObj.getHeight(); y++)
{
for(int x = 0; x < pictureObj.getWidth(); x++)
{
paletteTargetPixel = pictureObj.getPixel(x,y);
palettePixelColor = paletteTargetPixel.getColor();
if(paletteTargetPixel.getRed() >= 1 && paletteTargetPixel.getRed() <= 31)
palettePixelColor.setColor(palette[0]);
else if(paletteTargetPixel.getRed() >= 32 && paletteTargetPixel.getRed() <= 62)
palettePixelColor.setColor(palette[1]);
else if(paletteTargetPixel.retRed() >= 63 && paletteTargetPixel.getRed() <=93)
palettePixelColor.setColor(palette[2]);
}
}
}
}
public class ColorPaletteTester
{
public static void main(String[] args)
{
Picture pictureObj = new Picture("washingtonmonument.jpg"); //creates a new Picture object representing the file in the parameter list
pictureObj.explore();
ColorPalette cp = new ColorPalette();
cp.grayscaleEffect(pictureObj);
cp.paletteEffect(pictureObj);
}
}
So, the error is coming at
palettePixelColor.setColor(palette[0]);
Does anyone know why this would be happening?

palettePixelColor is declared as java.awt.Color, which happens to be an immutable class with no setters. Depending on what Pixel is, it may have such a method.
You are probably trying to do something like
palettePixelColor = palette[0];
or
paletteTargetPixel.setColor(palette[0]);

assign RGB values in java with nested for function

I have some question, here is my code :
int W = img.getWidth();
int H = img.getHeight();
int [][] pixels = new int [W][H];
int [][][] rgb = new int [3][H][W];
for(int i=0;i<W;i++)
for(int j=0;j<H;j++){
pixels[i][j] = img.getRGB(i,j);
Color clr = new Color(pixels[i][j]);
rgb[0][j][i] = clr.getRed();
rgb[1][j][i] = clr.getGreen();
rgb[2][j][i] = clr.getBlue();
}
/*
pixels changing process
*/
//1st for
for(int[] asd : rgb[0])
System.out.println(Arrays.toString(asd));
//2nd for
for(int i=0;i<W;i++)
for(int j=0;j<H;j++){
/*Color myColor = new Color (rgb[0][i][j],rgb[1][i][j],rgb[2][i][j]);
int newrgb = myColor.getRGB();
img.setRGB(W,H,newrgb);*/
}
}
printing the red values with 1st works normally, but why I can't put that values using 2nd for ?
when I run the code, it issues ByteInterleavedRaster.setDataElements(int, int, Object) line: not available
I want to assign image colors with new values of rgb[0] (red), rgb[1] (green), rgb[2] (blue) that printed by using 1st for. When I expected it could work with 2nd for, it threw an error.
thanks in advance :)

I think this looks correct
int W = img.getWidth();
int H = img.getHeight();
int [][] pixels = new int [W][H];
int [][][] rgb = new int [3][W][H];
for(int i=0; i<W; i++)
for(int j=0; j<H; j++) {
pixels[i][j] = img.getRGB(i,j);
Color clr = new Color(pixels[i][j]);
rgb[0][i][j] = clr.getRed();
rgb[1][i][j] = clr.getGreen();
rgb[2][i][j] = clr.getBlue();
}
/*
pixels changing process
*/
for(int i=0; i<W; i++)
for(int j=0; j<H; j++){
Color myColor = new Color (rgb[0][i][j],
rgb[1][i][j],
rgb[2][i][j]);
int newrgb = myColor.getRGB();
img.setRGB(i, j, newrgb);
}
}

You have to change this line img.setRGB(W,H,newrgb) to this one img.setRGB(j,i,newrgb).

Java replacing the background of an image

I am writing a program where I take one picture and replace the background of that picture.
The picture I have is:
And the background that I am using for the cat is:
I know that in order to this I have to use the cat picture and take the color pixels that are less than 255 because the red, green, and blue values for white are 255. So then I take those pixels that are less than 255, which make up the cat, and place it on the background picture in the same X and Y positions. The problem I am having is that I can not figure out how to code this to get it to work.
I have the basic code which is:
import java.awt.*;
public class TrueColors
{
public static void main(String [] args)
{
Picture pictureObj2 = new Picture("9.01 cat picture.jpg");
pictureObj2.explore();
int redValue = 0; int greenValue = 0; int blueValue = 0;
Pixel targetPixel = new Pixel(pictureObj2, 0, 0);
Color pixelColor = null;
for(int y = 0; y < pictureObj2.getHeight(); y++)
{
for(int x = 0; x < pictureObj2.getWidth(); x++)
{
targetPixel = pictureObj2.getPixel(x,y);
pixelColor = targetPixel.getColor();
redValue = pixelColor.getRed();
greenValue = pixelColor.getGreen();
blueValue = pixelColor.getBlue();
pixelColor = new Color(redValue, greenValue, blueValue);
targetPixel.setColor(pixelColor);
}
}
pictureObj2.explore();
pictureObj2.write("ColoredCat.jpg");
pictureObj2.show();
}
}
I was just wondering if you could help me figure out how to take the concept of this program that I understand and turn it into code
Thank you

What you have is almost correct. Simply read in your second picture like you have your first picture here:
Picture background = new Picture("background.png");
background.explore();
Then in your inner loop simply do:
targetPixel = pictureObj2.getPixel(x,y);
pixelColor = targetPixel.getColor();
if(!pixelColor.equals(WHITE)) //test if you have a blank pixel
background.getPixel(x,y).setColor(pixelColor); //if not its a cat pixel so add it on top of the background

Change color of non-transparent parts of png in Java

I am trying to automatically change the color for a set of icons.
Every icon has a white filled layer and the other part is transparent.
Here is an example: (in this case it's green, just to make it visible)
I tried to do the following:
private static BufferedImage colorImage(BufferedImage image) {
int width = image.getWidth();
int height = image.getHeight();
for (int xx = 0; xx < width; xx++) {
for (int yy = 0; yy < height; yy++) {
Color originalColor = new Color(image.getRGB(xx, yy));
System.out.println(xx + "|" + yy + " color: " + originalColor.toString() + "alpha: "
+ originalColor.getAlpha());
if (originalColor.equals(Color.WHITE) && originalColor.getAlpha() == 255) {
image.setRGB(xx, yy, Color.BLUE.getRGB());
}
}
}
return image;
}
The problem I have is that every pixel I get has the same value:
32|18 color: java.awt.Color[r=255,g=255,b=255]alpha: 255
So my result is just a colored square.
How can I achieve to change the color of the non-transparent parts only? And why is it, that all pixels have even the same alpha value? I guess that's my main problem: That the alpha value isn't read correctly.

Why it doesn't work, I don't know, this will.
This changes all the pixles to blue, maintaining their alpha values...
import java.awt.image.BufferedImage;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
public class TestColorReplace {
public static void main(String[] args) {
try {
BufferedImage img = colorImage(ImageIO.read(new File("NWvnS.png")));
ImageIO.write(img, "png", new File("Test.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
private static BufferedImage colorImage(BufferedImage image) {
int width = image.getWidth();
int height = image.getHeight();
WritableRaster raster = image.getRaster();
for (int xx = 0; xx < width; xx++) {
for (int yy = 0; yy < height; yy++) {
int[] pixels = raster.getPixel(xx, yy, (int[]) null);
pixels[0] = 0;
pixels[1] = 0;
pixels[2] = 255;
raster.setPixel(xx, yy, pixels);
}
}
return image;
}
}

The problem is, that
Color originalColor = new Color(image.getRGB(xx, yy));
discards all the alpha values. Instead you have to use
Color originalColor = new Color(image.getRGB(xx, yy), true);
to keep alpha values available.

If your bitmap is already set in an ImageView, just do :
imageView.setColorFilter(Color.RED);
to set all non transparent pixels to red.

Since we will always be replacing only the first three bands of the RGB pixel, more effective way to achieve the same without unnecessary allocation of new arrays would be:
private static void colorImageAndPreserveAlpha(BufferedImage img, Color c) {
WritableRaster raster = img.getRaster();
int[] pixel = new int[] {c.getRed(),c.getGreen(),c.getBlue()};
for (int x = 0; x < raster.getWidth(); x++)
for (int y = 0; y < raster.getHeight(); y++)
for (int b = 0; b < pixel.length; b++)
raster.setSample(x,y,b,pixel[b]);
}

Simple edge detection method Java

I am working on a method in Java to do some simple edge detection. I want to take the difference of two color intensities one at a pixel and the other at the pixel directly below it. The picture that I am using is being colored black no matter what threshold I put in for the method. I am not sure if my current method is just not computing what I need it to but I am at a loss what i should be tracing to find the issue.
Here is my method thus far:
public void edgeDetection(double threshold)
{
Color white = new Color(1,1,1);
Color black = new Color(0,0,0);
Pixel topPixel = null;
Pixel lowerPixel = null;
double topIntensity;
double lowerIntensity;
for(int y = 0; y < this.getHeight()-1; y++){
for(int x = 0; x < this.getWidth(); x++){
topPixel = this.getPixel(x,y);
lowerPixel = this.getPixel(x,y+1);
topIntensity = (topPixel.getRed() + topPixel.getGreen() + topPixel.getBlue()) / 3;
lowerIntensity = (lowerPixel.getRed() + lowerPixel.getGreen() + lowerPixel.getBlue()) / 3;
if(Math.abs(topIntensity - lowerIntensity) < threshold)
topPixel.setColor(white);
else
topPixel.setColor(black);
}
}
}

new Color(1,1,1) calls the Color(int,int,int) constructor of Color which takes values between 0 and 255. So your Color white is still basically black (well, very dark grey, but not enough to notice).
If you want to use the Color(float,float,float) constructor, you need float literals:
Color white = new Color(1.0f,1.0f,1.0f);

public void edgeDetection(int edgeDist)
{
Pixel leftPixel = null;
Pixel rightPixel = null;
Pixel bottomPixel=null;
Pixel[][] pixels = this.getPixels2D();
Color rightColor = null;
boolean black;
for (int row = 0; row < pixels.length; row++)
{
for (int col = 0;
col < pixels[0].length; col++)
{
black=false;
leftPixel = pixels[row][col];
if (col<pixels[0].length-1)
{
rightPixel = pixels[row][col+1];
rightColor = rightPixel.getColor();
if (leftPixel.colorDistance(rightColor) >
edgeDist)
black=true;
}
if (row<pixels.length-1)
{
bottomPixel =pixels[row+1][col];
if (leftPixel.colorDistance(bottomPixel.getColor())>edgeDist)
black=true;
}
if (black)
leftPixel.setColor(Color.BLACK);
else
leftPixel.setColor(Color.WHITE);
}
}
}