Static function to check if the RGB error of BufferdImage is within the specified ratio in Java

	/**
	 *Pixel-by-pixel Red,Green,Assert the element value of the Blue color.
	 * 
	 *Difference in element values(±)Increases or decreases 5%Is allowed.
	 */
	static void assertImages(BufferedImage actual, BufferedImage expected) {
		assertThat("The image size being compared is different (vertical)", actual.getHeight(), is(expected.getHeight()));
		assertThat("The image size being compared is different (horizontal)", actual.getWidth(), is(expected.getWidth()));

		//Percentage tolerate error
		final int ACCEPTABLE_PERCENTAGE = 5;
		//Numerical value tolerate error(±)
		final int ACCEPTABLE_DIFFERENCE = 255 * ACCEPTABLE_PERCENTAGE / 100 / 2;

		int width = actual.getWidth();
		int height = actual.getHeight();
		for (int y = 0; y < height; y++) {
			for (int x = 0; x < width; x++) {
				Color actualColor = new Color(actual.getRGB(x, y));
				Color expectedColor = new Color(expected.getRGB(x, y));

				assertThat("Color element values are acceptable(±" + ACCEPTABLE_PERCENTAGE + "%)Beyond: Red",
						(double) actualColor.getRed(),
						is(closeTo((double) expectedColor.getRed(), ACCEPTABLE_DIFFERENCE)));

				assertThat("Color element values are acceptable(±" + ACCEPTABLE_PERCENTAGE + "%)Beyond: Green",
						(double) actualColor.getGreen(),
						is(closeTo((double) expectedColor.getGreen(), ACCEPTABLE_DIFFERENCE)));

				assertThat("Color element values are acceptable(±" + ACCEPTABLE_PERCENTAGE + "%)Beyond: Blue",
						(double) actualColor.getBlue(),
						is(closeTo((double) expectedColor.getBlue(), ACCEPTABLE_DIFFERENCE)));
			}
		}
	}

Recommended Posts