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import org.junit.Assert;
import org.junit.Test;
import org.junit.internal.InexactComparisonCriteria;
public class Tests {
// Tolerance used to compare two floating point numbers
private static final float EPSILON = 0.0001f;
// Check whether value is equal to expected integer
private void assertEquals(int expected, int actual) {
Assert.assertEquals(expected, actual);
}
// Check whether value is approximately equal to expected floating point number
private void assertEquals(float expected, float actual) {
Assert.assertEquals(expected, actual, EPSILON);
}
// Check whether integer array has correct size and values
private void assertEquals(int[] expected, int[] actual) {
Assert.assertArrayEquals(expected, actual);
}
// Check whether integer two-dimensional array has correct size and values
private void assertEquals(int[][] expected, int[][] actual) {
Assert.assertArrayEquals(expected, actual);
}
// Check whether floating point two-dimensional array has correct size and similar values
private void assertEquals(float[][] expected, float[][] actual) {
new InexactComparisonCriteria(EPSILON).arrayEquals(null, expected, actual);
}
// Test based on example in section 3.1 (pixel coding)
@Test
public void testColorSinglePixel() {
// Check RGB components and gray level of this bluish color
int color = 0b00100000_11000000_11111111;
assertEquals(0.1254902f, Color.getRed(color));
assertEquals(0.7529412f, Color.getGreen(color));
assertEquals(1.0f, Color.getBlue(color));
assertEquals(0.6261438f, Color.getGray(color));
// Encode some colors
assertEquals(0x0000ff, Color.getRGB(0.0f, 0.0f, 1.0f));
assertEquals(0x7f7f7f, Color.getRGB(0.5f));
assertEquals(0x0000ff, Color.getRGB(-0.5f, 0, 2));
assertEquals(0x000000, Color.getRGB(-1.0f));
}
// Test based on example in section 3.2 (image coding)
@Test
public void testColorWholeImage() {
// A 2x2 image
int[][] image = {
{0x20c0ff, 0x123456},
{0xffffff, 0x000000}
};
// Convert to grayscale
float[][] gray = {
{0.62614375f, 0.20392157f},
{1.0f, 0.0f}
};
assertEquals(gray, Color.toGray(image));
// Convert back to integer representation
int[][] back = {
{0x9f9f9f, 0x343434},
{0xffffff, 0x000000}
};
assertEquals(back, Color.toRGB(gray));
}
// Test based on example in section 4.1 (image filtering)
@Test
public void testFilterConvolution() {
// A 2x2 grayscale image
float[][] gray = {
{0.5f, 1.0f},
{0.2f, 0.0f}
};
// Access some pixels
assertEquals(0.5f, Filter.at(gray, 0, 0));
assertEquals(0.2f, Filter.at(gray, 1, 0));
assertEquals(0.2f, Filter.at(gray, 2, -1));
// Apply smoothing and Sobel
assertEquals(new float[][]{
{0.49f, 0.62f},
{0.3f, 0.29f}
}, Filter.smooth(gray));
assertEquals(new float[][]{
{1.3f, 1.3f},
{-0.1f, -0.1f}
}, Filter.sobelX(gray));
assertEquals(new float[][]{
{-1.9f, -3.3f},
{-1.9f, -3.3f}
}, Filter.sobelY(gray));
assertEquals(new float[][]{
{2.302173f, 3.5468295f},
{1.9026297f, 3.3015149f}
}, Filter.sobel(gray));
}
// Test based on example in section 5.1 (shortest path)
@Test
public void testSeamPath() {
// Simple graph stored as an adjacency list
int[][] successors = new int[][]{
/* 0 -> */ {1, 3},
/* 1 -> */ {2},
/* 2 -> */ {},
/* 3 -> */ {4},
/* 4 -> */ {1, 5},
/* 5 -> */ {2}
};
float[] costs = new float[]{
/* 0 : */ 1.0f,
/* 1 : */ 9.0f,
/* 2 : */ 2.0f,
/* 3 : */ 1.0f,
/* 4 : */ 3.0f,
/* 5 : */ 1.0f
};
// Compute and check shortest path
int[] vertices = Seam.path(successors, costs, 0, 2);
assertEquals(new int[]{0, 3, 4, 5, 2}, vertices);
}
// Test based on example in section 5.2 (resizing)
@Test
public void testSeamResize() {
// A 3x3 image
int[][] image = {
{0x888888, 0x666666, 0xcccccc},
{0x000000, 0x111111, 0x222222},
{0xbbbbbb, 0xffffff, 0x666666}
};
float[][] gray = Color.toGray(image);
// Find best seam, using gray level as energy
int[] seam = Seam.find(gray);
assertEquals(new int[]{1, 1, 2}, seam);
// Remove seam
int[][] resized = Seam.shrink(image, seam);
assertEquals(new int[][]{
{0x888888, 0xcccccc},
{0x000000, 0x222222},
{0xbbbbbb, 0xffffff}
}, resized);
}
}
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