PImpLab11-ImageProcessing/src/imagefilters/ImageFilters.scala

package imagefilters

import java.awt.Color

/**
 * This class implements the various image filters
 */
object ImageFilters {
  // Default factors (reference values)
  /*val SEPIA_FACTORS: Array[Array[Double]] = Array(
    Array( 0.393, 0.769, 0.189),
    Array( 0.349, 0.686, 0.168),
    Array( 0.272, 0.534, 0.131)
  )*/

  // Adapted factors (matches the example in the instructions)
  val SEPIA_FACTORS: Array[Array[Double]] = Array(
    Array( 0.883, 0.004, 0.003),
    Array(-0.058, 0.791,-0.097),
    Array( 0.034,-0.244, 0.583)
  )

  def filter(src: Array[Array[Int]], func: (Int, Int, Int, Int, Int) => Int): Array[Array[Int]] = {
    val width: Int = src.length
    val height: Int = if (width == 0) 0 else src(0).length
    val dst: Array[Array[Int]] = Array.ofDim(width, height)
    for (x: Int <- 0 until width) {
      for (y: Int <- 0 until height) {
        dst(x)(y) = func(src(x)(y), x, y, width, height)
      }
    }
    return dst
  }
  def filter(src: Array[Array[Int]], func: (Int) => Int): Array[Array[Int]] = filter(src, (value, x, y, width, height) => func(value))
  def colorFilter(src: Array[Array[Color]], func: (Color, Int, Int, Int, Int) => Color): Array[Array[Color]] = {
    val width: Int = src.length
    val height: Int = if (width == 0) 0 else src(0).length
    val dst: Array[Array[Color]] = Array.ofDim(width, height)
    for (x: Int <- 0 until width) {
      for (y: Int <- 0 until height) {
        dst(x)(y) = func(src(x)(y), x, y, width, height)
      }
    }
    return dst
  }
  def colorFilter(src: Array[Array[Color]], func: (Color) => Color): Array[Array[Color]] = colorFilter(src, (value, x, y, width, height) => func(value))

  def duplicate(a: Array[Array[Int]]): Array[Array[Int]] = filter(a, (value) => value)
  def threshold(a: Array[Array[Int]], thresh: Int): Array[Array[Int]] = filter(a, (value) => if (value > thresh) 255 else 0)
  def mean(a: Array[Array[Int]]): Array[Array[Int]] = filter(a, (value, x, y, width, height) => {
    if (x == 0 || x == width - 1 || y == 0 || y == height - 1) value
    else {
      var avg: Double = 0
      for (dx: Int <- -1 to 1) {
        for (dy: Int <- -1 to 1) {
          avg += a(x+dx)(y+dy)
        }
      }
      (avg/9.0).toInt
    }
  })
  def mean(a: Array[Array[Int]], radius: Int): Array[Array[Int]] = {
    if (radius < 0) throw new IllegalArgumentException("radius must be >= 0")
    val diameter: Int = 2 * radius + 1

    filter(a, (value, x, y, width, height) => {
      if (x <= radius - 1 || x >= width - radius || y <= radius - 1 || y >= height - radius) value
      else {
        var avg: Double = 0
        for (dx: Int <- -radius to radius) {
          for (dy: Int <- -radius to radius) {
            avg += a(x+dx)(y+dy)
          }
        }
        (avg/(diameter * diameter)).toInt
      }
    })
  }

  def edges(a: Array[Array[Int]]): Array[Array[Int]] = filter(a, (value, x, y, width, height) => {
    if (x == 0 || x == width - 1 || y == 0 || y == height - 1) value
    else {
      val dx: Int = a(x+1)(y) - a(x-1)(y)
      val dy: Int = a(x)(y+1) - a(x)(y-1)
      Math.sqrt(dx*dx + dy*dy).toInt
    }
  })

  def sobel(a: Array[Array[Int]], intensityFactor: Double): Array[Array[Int]] = filter(a, (value, x, y, width, height) => {
    if (x == 0 || x == width - 1 || y == 0 || y == height - 1) value
    else {
      val dx: Int = a(x+1)(y-1) + 2*a(x+1)(y) + a(x+1)(y+1) - a(x-1)(y-1) - 2*a(x-1)(y) - a(x-1)(y+1)
      val dy: Int = a(x-1)(y+1) + 2*a(x)(y+1) + a(x+1)(y+1) - a(x-1)(y-1) - 2*a(x)(y-1) - a(x+1)(y-1)
      (Math.sqrt(dx*dx + dy*dy)*intensityFactor).toInt
    }
  })

  def noise(a: Array[Array[Int]], intensity: Double): Array[Array[Int]] = filter(a, (value) => {
    Math.max(0, Math.min(255, value + (Math.random()*2-1)*intensity)).toInt
  })

  def noise(a: Array[Array[Color]], intensity: Double): Array[Array[Color]] = colorFilter(a, (col) => {
    val r: Double = col.getRed + (Math.random()*2-1)*intensity
    val g: Double = col.getGreen + (Math.random()*2-1)*intensity
    val b: Double = col.getBlue + (Math.random()*2-1)*intensity
    new Color(
      Math.max(0, Math.min(255, r)).toInt,
      Math.max(0, Math.min(255, g)).toInt,
      Math.max(0, Math.min(255, b)).toInt
    )
  })

  def mask(a: Array[Array[Color]], maskImg: Array[Array[Int]]): Array[Array[Color]] = {
    val maskWidth: Int = maskImg.length
    val maskHeight: Int = if (maskWidth == 0) 0 else maskImg(0).length

    colorFilter(a, (col, x, y, width, height) => {
      if (x >= maskWidth || y >= maskHeight) col
      else {
        val factor: Double = maskImg(x)(y)/255.0
        new Color(
          (col.getRed * factor).toInt,
          (col.getGreen * factor).toInt,
          (col.getBlue * factor).toInt
        )
      }
    })
  }

  def getAvgInPixel(a: Array[Array[Color]], pixelSize: Int, px: Int, py: Int): Color = {
    val width: Int = a.length
    val height: Int = if (width == 0) 0 else a(0).length
    var r: Double = 0
    var g: Double = 0
    var b: Double = 0
    var cnt: Int = 0
    for (x: Int <- px*pixelSize until (px+1)*pixelSize) {
      for (y: Int <- py*pixelSize until (py+1)*pixelSize) {
        if (x < width && y < height) {
          cnt += 1
          r += a(x)(y).getRed
          g += a(x)(y).getGreen
          b += a(x)(y).getBlue
        }
      }
    }
    return new Color((r/cnt).toInt, (g/cnt).toInt, (b/cnt).toInt)
  }
  def pixelize(a: Array[Array[Color]], pixelSize: Int): Array[Array[Color]] = {
    val width: Int = a.length
    val height: Int = if (width == 0) 0 else a(0).length
    val hPixels: Int = Math.ceil(width.toDouble/pixelSize).toInt
    val vPixels: Int = Math.ceil(height.toDouble/pixelSize).toInt
    val pixels: Array[Array[Color]] = Array.ofDim[Color](hPixels, vPixels)
    for (x: Int <- 0 until hPixels) {
      for (y: Int <- 0 until vPixels) {
        pixels(x)(y) = getAvgInPixel(a, pixelSize, x, y)
      }
    }

    colorFilter(a, (col, x, y, w, h) => pixels(x/pixelSize)(y/pixelSize))
  }

  def pixelize(a: Array[Array[Color]], pixelSize: Int, x1: Int, y1: Int, x2: Int, y2: Int): Array[Array[Color]] = {
    val pixelated: Array[Array[Color]] = pixelize(a, pixelSize)
    colorFilter(a, (col, x, y, w, h) => {
      if (x1 <= x && x <= x2 && y1 <= y && y <= y2) {
        pixelated(x)(y)
      }
      else col
    })
  }

  def sepia(a: Array[Array[Color]]): Array[Array[Color]] = colorFilter(a, (col) => {
    val r: Double = Math.max(0, Math.min(255, col.getRed   * SEPIA_FACTORS(0)(0) +
                                              col.getGreen * SEPIA_FACTORS(0)(1) +
                                              col.getBlue  * SEPIA_FACTORS(0)(2)))

    val g: Double = Math.max(0, Math.min(255, col.getRed   * SEPIA_FACTORS(1)(0) +
                                              col.getGreen * SEPIA_FACTORS(1)(1) +
                                              col.getBlue  * SEPIA_FACTORS(1)(2)))

    val b: Double = Math.max(0, Math.min(255, col.getRed   * SEPIA_FACTORS(2)(0) +
                                              col.getGreen * SEPIA_FACTORS(2)(1) +
                                              col.getBlue  * SEPIA_FACTORS(2)(2)))

    new Color(r.toInt, g.toInt, b.toInt)
  })
}