Android Open Source - 4est Bitmap

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License

The source code is released under:
MIT License
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Java Source Code

package com.wordsaretoys.rise.pattern;
//from  ww  w .  java 2s . c  o  m
import java.util.Random;

/**
 * provides utility methods for creating texture bitmaps
 */
public class Bitmap {

  static int Black = toRGBA(0, 0, 0, 1);
  
  /**
   * convert 4 color values to RGBA value
   */
  public static int toRGBA(float r, float g, float b, float a) {
    int br = (int)(r * 255) & 0xff;
    int bg = (int)(g * 255) & 0xff;
    int bb = (int)(b * 255) & 0xff;
    int ba = (int)(a * 255) & 0xff;
    return br + (bg << 8) + (bb << 16) + (ba << 24);
  }

  /**
   * interpolate between two RGBA color values
   */
  public static int mixRGBA(int c1, int c2, float mu) {
    float um = 1 - mu;
  
    int r1 = c1 & 0xff;
    int g1 = (c1 >> 8) & 0xff;
    int b1 = (c1 >> 16) & 0xff;
    int a1 = (c1 >> 24) & 0xff;
  
    int r2 = c2 & 0xff;
    int g2 = (c2 >> 8) & 0xff;
    int b2 = (c2 >> 16) & 0xff;
    int a2 = (c2 >> 24) & 0xff;
    
    int r = (int)(um * r1 + mu * r2) & 0xff;
    int g = (int)(um * g1 + mu * g2) & 0xff;
    int b = (int)(um * b1 + mu * b2) & 0xff;
    int a = (int)(um * a1 + mu * a2) & 0xff;
    
    return r + (g << 8) + (b << 16) + (a << 24);
  }

  /**
   * scale the color elements of an RGBA value by specified factor
   * will NOT scale alpha channel
   */
  public static int scaleRGBA(int c, float s) {
    int r = c & 0xff;
    int g = (c >> 8) & 0xff;
    int b = (c >> 16) & 0xff;
    int a = (c >> 24) & 0xff;
    
    r = (int)(r * s) & 0xff;
    g = (int)(g * s) & 0xff;
    b = (int)(b * s) & 0xff;
    
    return r + (g << 8) + (b << 16) + (a << 24);
  }
  
  /**
   * returns interpolated color from a color table and normalized value
   */
  public static int getColor(int[] table, float value) {
    float f = value * (table.length - 1);
    int i = (int)(f);
    float mu = f - i;
    return mixRGBA(table[i], table[i + 1], mu);
  }
  
  /**
   * recursively evolve a color pattern onto a bitmap
   */
  public static class Divider {
    
    Random rng = new Random();
    int[] bitmap;
    int size;
    int[] color;
    float coeff;
    
    public int[] apply(int s, int[] c) {
      bitmap = new int[s * s];
      size = s;
      color = c;
      coeff = 1f / (float)(Math.log(s) / Math.log(2));
      descend(0, 0, size, 0);
      return bitmap;
    }
    
    void descend(int x, int y, int sz, float t) {
      t += rng.nextFloat();
      if (sz == 1) {
        int i = y * size + x;
        bitmap[i] = getColor(color, t * coeff);
        return;
      }
      sz = sz >> 1;
      descend(x, y, sz, t);
      descend(x + sz, y, sz, t);
      descend(x + sz, y + sz, sz, t);
      descend(x, y + sz, sz, t);
    }
    
  }

  /**
   * recursively evolve a mixing pattern onto a bitmap
   */
  public static class MixMaster {
    
    Random rng = new Random();
    int[] bitmap;
    float coeff;
    int size;
    int cut;
    
    public int[] apply(int s, int c) {
      bitmap = new int[s * s];
      size = s;
      cut = c;
      coeff = 1f / (float)Math.floor(Math.log(c) / Math.log(2));
      descend(0, 0, size, 0, 0, 0, 0);
      return bitmap;
    }
    
    void descend(int x, int y, int sz, float r, float g, float b, float a) {
      if (sz < cut) {
        r += rng.nextFloat();
        g += rng.nextFloat();
        b += rng.nextFloat();
        a += rng.nextFloat();
      }
      if (sz == 1) {
        int i = y * size + x;
        bitmap[i] = toRGBA(r * coeff, g * coeff, b * coeff, a * coeff);
        return;
      }
      sz = sz >> 1;
      descend(x, y, sz, r, g, b, a);
      descend(x + sz, y, sz, r, g, b, a);
      descend(x + sz, y + sz, sz, r, g, b, a);
      descend(x, y + sz, sz, r, g, b, a);
    }
    
  }
  
}
Java Source Code List
