PixelData.java

// PixelData.java

import javax.microedition.lcdui.*;

public class PixelData {
  private int[] pixels;
  private int width;
  private int height;

  private PixelData(int[] pixels, int width, int height)
    {
      this.pixels = pixels;
      this.width  = width;
      this.height = height;
    }

  public PixelData(int width, int height)
    {
      this(new int[width * height], width, height);
    }

  public static PixelData createPixelData(String filename)
    throws java.io.IOException
    {
      Image img = Image.createImage(filename);
      int[] pixels = new int[img.getWidth() * img.getHeight()];
      img.getRGB(pixels, 0, img.getWidth(), 0, 0, img.getWidth(), img.getHeight());
      return new PixelData(pixels, img.getWidth(), img.getHeight());
    }

  private int index(int x, int y)
    {
      return y * this.width + x;
    }

  public int getPixel(int x, int y)
    {
      // 座標値を画像の中に収める
      if (x < 0) x = 0;
      if (x >= this.getWidth()) x = this.getWidth() - 1;
      if (y < 0) y = 0;
      if (y >= this.getHeight()) y = this.getHeight() - 1;

      return this.pixels[index(x, y)];
    }

  private int bilinearColorInterpolate(int c1, int c2, double p)
    {
      // p*c2 + (1 - p)*c1

      int r1 = (c1 >> 16) & 0xff;
      int g1 = (c1 >>  8) & 0xff;
      int b1 = (c1 >>  0) & 0xff;

      int r2 = (c2 >> 16) & 0xff;
      int g2 = (c2 >>  8) & 0xff;
      int b2 = (c2 >>  0) & 0xff;

      double r = p*r2 + (1 - p)*r1;
      if (r < 0) r = 0;
      if (r > 255) r = 255;
      double g = p*g2 + (1 - p)*g1;
      if (g < 0) g = 0;
      if (g > 255) g = 255;
      double b = p*b2 + (1 - p)*b1;
      if (b < 0) b = 0;
      if (b > 255) b = 255;

      return ((int)r << 16) | ((int)g << 8) | (int)b;
    }

  public int getPixelBilinear(double x, double y)
    {
      //       |      :     |
      // y1----------------------
      //      q|      :     |q
      // y*....o......%.....o....
      //       |  p   : 1-p |
      //    1-q|      :     |1-q
      //       |      :     |
      // y2----------------------
      //       |      :     |
      //       x1     x     x2
      //
      // p = x* - x1,  q = y* - y1
      //
      // f(x1, y*) = q*f(x1, y2) + (1-q)*f(x1, y1)
      // f(x2, y*) = q*f(x2, y2) + (1-q)*f(x2, y1)
      //
      // f(x*, y*) = p*f(x2, y*) + (1-p)*f(x1, y*)
      //           = pq*f(x2, y2) + p(1-q)*f(x2, y1) +
      //             (1-p)q*f(x1, y2) + (1-p)(1-q)*f(x1, y1)
      int x1 = (int)x;
      int y1 = (int)y;
      double p = x - x1;
      double q = y - y1;

      int c11 = getPixel(x1,     y1);
      int c12 = getPixel(x1,     y1 + 1);
      int c21 = getPixel(x1 + 1, y1);
      int c22 = getPixel(x1 + 1, y1 + 1);

      int r11 = (c11 >> 16) & 255;
      int r12 = (c12 >> 16) & 255;
      int r21 = (c21 >> 16) & 255;
      int r22 = (c22 >> 16) & 255;
      int r   = (int)(p*q*r22 + p*(1-q)*r21 +
                      (1-p)*q*r12 + (1-p)*(1-q)*r11);
      if (r < 0) r = 0; else if (r > 255) r = 255;

      int g11 = (c11 >>  8) & 255;
      int g12 = (c12 >>  8) & 255;
      int g21 = (c21 >>  8) & 255;
      int g22 = (c22 >>  8) & 255;
      int g   = (int)(p*q*g22 + p*(1-q)*g21 +
                      (1-p)*q*g12 + (1-p)*(1-q)*g11);
      if (g < 0) g = 0; else if (g > 255) g = 255;

      int b11 = (c11 >>  0) & 255;
      int b12 = (c12 >>  0) & 255;
      int b21 = (c21 >>  0) & 255;
      int b22 = (c22 >>  0) & 255;
      int b   = (int)(p*q*b22 + p*(1-q)*b21 +
                      (1-p)*q*b12 + (1-p)*(1-q)*b11);
      if (b < 0) b = 0; else if (b > 255) b = 255;

      return (r << 16) | (g << 8) | b;
    }

  public void setPixel(int x, int y, int v)
    {
      // 座標値が画像内だったらピクセルをセットする
      if (0 <= x && x <= this.getWidth() - 1 &&
          0 <= y && y <= this.getHeight() - 1)
        this.pixels[index(x, y)] = v;
    }

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

  public Image createRGBImage()
    {
      return Image.createRGBImage(this.pixels, this.width, this.height, false);
    }

  // fill a given rectangle area
  //
  // @param x  x-coordinate of the filling rectangle
  // @param y  y-coordinate of the filling rectangle
  // @param w  width of the filling rectangle
  // @param h  height of the filling rectangle
  // @param c  fill color
  public void fillRect(int x, int y, int w, int h, int c)
    {
      for (int i = 0; i < h && i + y < getHeight(); ++i) {
        for (int j = 0; j < w && j + x < getWidth(); ++j) {
          this.pixels[index(j + x, i + y)] = c;
        }
      }
    }
}