// pixels may contain any float number (e.g. for a distance map)
static final class FloatBWImage is IBWImage {
  int width, height;
  float[] pixels; // 0 to 1 usually

  // color returned when getPixel is called with a position outside the actual image
  float borderColor = 0.0f;
  
  // for unstructure()
  *() {}

  // BLACK!
  *(int *width, int *height) {
    pixels = new float[width*height];
  }

  *(int *width, int *height, float brightness) {
    pixels = new float[width*height];
    fillArrayUnlessZero(pixels, brightness);
  }
  
  *(int *width, int *height, float[] *pixels) {}

  public float getPixel aka getFloatPixel(int x, int y) {
    ret inRange(x, y) ? getPixel_noRangeCheck(x, y) : borderColor;
  }
  
  public float getFloatPixel(int index) {
    ret pixels[index];
  }
  
  float getPixel(Pt p) { ret getPixel(p.x, p.y); }

  private boolean inRange(int x, int y) {
    return x >= 0 && x < width && y >= 0 && y < height;
  }

  public int getWidth() { return width; }
  public int getHeight() { return height; }

  public void setPixel(int x, int y, float brightness) {
    pixels[y*width+x] = brightness;
  }
  
  float getPixel_noRangeCheck(int x, int y) {
    return pixels[y*width+x];
  }
  
  public byte getByte(int x, int y) {
    return inRange(x, y) ? getByte_noRangeCheck(x, y) : _toByte(borderColor);
  }
  
  byte getByte_noRangeCheck(int x, int y) {
    ret _toByte(pixels[y*width+x]);
  }
  
  static byte _toByte(float pixel) {
    return (byte) (Math.max(0, Math.min(1, pixel))*255f);
  }

  // TODO: optimize
  public BufferedImage getBufferedImage() {
    BufferedImage img = bufferedImage(width, height);
    for (int y = 0; y < height; y++)
      for (int x = 0; x < width; x++) {
        int b = ((int) getByte(x, y) & 0xFF);
        img.setRGB(x, y, b*0x010101);
      }
    ret img; 
  }
  
  public double averageBrightness() {
    ret floatSumAsDouble(pixels)/(width*height);
  }
}