CODEWITHSUNDEEP
javajava-2d
DarkSun
DarkSun

Reputation: 449

Java2D: if statement doesn`t work with java.awt.Color

I have a getPixelColour function: 

Color getPixelColor(int x, int y) {
    if(mazeImage == null) System.out.println(":(");
    int pixel = mazeImage.getRGB(x, y);
    int  red = (pixel & 0x00ff0000) >> 16;
    int  green = (pixel & 0x0000ff00) >> 8;
    int  blue = pixel & 0x000000ff;
    return new Color(red,green,blue);
}

For example a pixel is black, and System.out.println(getPixelColor(x,y) + " " + Color.BLACK); writes java.awt.Color[r=0,g=0,b=0] java.awt.Color[r=0,g=0,b=0]

But getPixelColor(x,y) == Color.BLACK returns false. What's wrong with it?

Upvotes: 2

Views: 367

Answers (4)

darrengorman
darrengorman

Reputation: 13116

Instead of using getPixelColor(x, y) == Color.BLACK try Color.BLACK.equals(getPixelColor(x, y))

You should also read up on the equals method in Java and when it is appropriate to use it vs. the == operator.

Upvotes: 4

A.H.
A.H.

Reputation: 66233

Color is an object and == compares not the contents of the objects but the instances. So there can be several Color objects containing the RGB values (0,0,0).

You want to compare with col1.equals(col2).

You might look around this site and find plenty of other questions regaring == and equals. As an example:

Java String.equals versus ==

Upvotes: 2

Simeon Visser
Simeon Visser

Reputation: 122336

You are comparing two different Color objects which will return false (i.e., two different objects at different memory locations).

If you wish to properly compare them, use equals():

getPixelColor(x, y).equals(Color.BLACK);

Upvotes: 4

Gareth Davis
Gareth Davis

Reputation: 28059

If you do

getPixelColor(x,y).equals(Color.BLACK);

I'm sure you will get the result you expect.

The == operator in java is reference equality, and since getPixelColor() returns a new instance of Color it'll never == to Color.BLACK as this a static reference to another instance that happens to be the colour black.

Upvotes: 2

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