Is there a simple way to compare BufferedImage instances?

Question

I am working on part of a Java application that takes an image as a byte array, reads it into a java.awt.image.BufferedImage instance and passes it to a third-p

Answer 1

If you want to use Mockito, then you could write a Hamcrest Matcher

import org.mockito.ArgumentMatcher;

public class BufferedImageMatcher extends ArgumentMatcher {

  private final BufferedImage expected;

  public BufferedImageMatcher(BufferedImage expected) {
    this.expected = expected;
  }

  @Override
  public boolean matches(Object argument) {
    BufferedImage actual = (BufferedImage) argument;

    assertEquals(expected.getWidth(), actual.getWidth());
    assertEquals(expected.getHeight(), actual.getHeight());

    for (int x = 0; x < actual.getWidth(); x++) {
      for (int y = 0; y < actual.getHeight(); y++) {
        assertEquals(expected.getRGB(x, y), actual.getRGB(x, y));
      }
    }

    return true;
  }
}

and use it like this

assertThat(actual, new BufferedImageMatcher(expected));