/// <summary>
/// boxBlur() returns a blurred version of "this" PixImage.
///
/// If numIterations == 1, each pixel in the output PixImage is assigned
/// a value equal to the average of its neighboring pixels in "this" PixImage,
/// INCLUDING the pixel itself.
///
/// A pixel not on the image boundary has nine neighbors--the pixel itself and
/// the eight pixels surrounding it. A pixel on the boundary has six
/// neighbors if it is not a corner pixel; only four neighbors if it is
/// a corner pixel. The average of the neighbors is the sum of all the
/// neighbor pixel values (including the pixel itself) divided by the number
/// of neighbors, with non-integer quotients rounded toward zero (as C# does
/// naturally when you divide two integers).
///
/// Each color (red, green, blue) is blurred separately. The red input should
/// have NO effect on the green or blue outputs, etc.
///
/// The parameter numIterations specifies a number of repeated iterations of
/// box blurring to perform. If numIterations is zero or negative, "this"
/// PixImage is returned (not a copy). If numIterations is positive, the
/// return value is a newly constructed PixImage.
///
/// IMPORTANT: DO NOT CHANGE "this" PixImage!!! All blurring/changes should
/// appear in the new, output PixImage only.
/// </summary>
/// <param name="numIterations"> the number of iterations of box blurring. </param>
/// <returns> a blurred version of "this" PixImage. </returns>
public virtual PixImage BoxBlur(int numIterations)
{
if (numIterations > 0)
{
//make a new image
var newImage = new PixImage(this.Width, this.Height);
for (int i = 0; i < this.Width; i++)
{
for (int j = 0; j < this.Height; j++)
{
Pixel newPixel = this.GetBlurredPixel(i, j);
newImage.setPixel(i, j, newPixel.Red, newPixel.Green, newPixel.Blue);
// Console.WriteLine("At pixel {0},{1}: {2}, {3}, {4}. Counter: {5}", i, j, red, green, blue, counter);
}
}
for (int n = 0; n < numIterations; n++)
{
newImage = newImage.BoxBlur(n);
}
return(newImage);
}
return(this);
}
/// <summary>
/// main() runs a series of tests to ensure that the convolutions (box blur
/// and Sobel) are correct.
/// </summary>
public static void Main(string[] args)
{
// Be forwarned that when you write arrays directly in C# as below,
// each "row" of text is a column of your image--the numbers get
// transposed.
PixImage image1 = array2PixImage(new int[][]
{
new int[] { 0, 10, 240 },
new int[] { 30, 120, 250 },
new int[] { 80, 250, 255 }
});
Console.WriteLine("Testing getWidth/getHeight on a 3x3 image. " + "Input image:");
Console.Write(image1);
doTest(image1.Width == 3 && image1.Height == 3, "Incorrect image width and height.");
Console.WriteLine("Testing blurring on a 3x3 image.");
doTest(image1.BoxBlur(1).Equals(array2PixImage(new int[][]
{
new int[] { 40, 108, 155 },
new int[] { 81, 137, 187 },
new int[] { 120, 164, 218 }
})), "Incorrect box blur (1 rep):\n" + image1.BoxBlur(1));
doTest(image1.BoxBlur(2).Equals(array2PixImage(new int[][]
{
new int[] { 91, 118, 146 },
new int[] { 108, 134, 161 },
new int[] { 125, 151, 176 }
})), "Incorrect box blur (2 rep):\n" + image1.BoxBlur(2));
doTest(image1.BoxBlur(2).Equals(image1.BoxBlur(1).BoxBlur(1)), "Incorrect box blur (1 rep + 1 rep):\n" + image1.BoxBlur(2) + image1.BoxBlur(1).BoxBlur(1));
Console.WriteLine("Testing edge detection on a 3x3 image.");
doTest(image1.SobelEdges().Equals(array2PixImage(new int[][]
{
new int[] { 104, 189, 180 },
new int[] { 160, 193, 157 },
new int[] { 166, 178, 96 }
})), "Incorrect Sobel:\n" + image1.SobelEdges());
PixImage image2 = array2PixImage(new int[][]
{
new int[] { 0, 100, 100 },
new int[] { 0, 0, 100 }
});
Console.WriteLine("Testing getWidth/getHeight on a 2x3 image. " + "Input image:");
Console.Write(image2);
doTest(image2.Width == 2 && image2.Height == 3, "Incorrect image width and height.");
Console.WriteLine("Testing blurring on a 2x3 image.");
doTest(image2.BoxBlur(1).Equals(array2PixImage(new int[][]
{
new int[] { 25, 50, 75 },
new int[] { 25, 50, 75 }
})), "Incorrect box blur (1 rep):\n" + image2.BoxBlur(1));
Console.WriteLine("Testing edge detection on a 2x3 image.");
doTest(image2.SobelEdges().Equals(array2PixImage(new int[][]
{
new int[] { 122, 143, 74 },
new int[] { 74, 143, 122 }
})), "Incorrect Sobel:\n" + image2.SobelEdges());
Console.ReadLine();
}