Android – Material design color palette

Google has designed a color palette. Given a color, I want to dynamically create the palette in Android.

There was a similar question in the Graphic Design site and an open source javascript solution which generates a similar color palette. The factors for each color are found here and the function used to create the color is found in this stackoverflow answer.

I used that answer and project to generate a palette that is similar to Google's. However, I want an algorithm that would return the exact values which Google has generated (see the first link).

Question: How does Google calculate the palette colors for material design?

What I have tried so far:

Based off the information above, I created this example to show how I generated a similar palette. Again, I want the exact values.

import android.app.Activity;
import android.app.AlertDialog;
import android.graphics.Color;
import android.os.AsyncTask;
import android.view.Gravity;
import android.widget.LinearLayout;
import android.widget.ScrollView;
import android.widget.TextView;

import java.lang.ref.WeakReference;
import java.util.LinkedList;
import java.util.List;

/**
 * @author Jared Rummler <jared.rummler@gmail.com>
 */
public class PaletteTask extends AsyncTask<Integer, Void, List<PaletteTask.Shade>> {

  private static int shadeColor(int color, double percent) {
    return shadeColor(String.format("#%06X", (0xFFFFFF & color)), percent);
  }

  private static int shadeColor(String color, double percent) {
    long f = Long.parseLong(color.substring(1), 16);
    double t = percent < 0 ? 0 : 255;
    double p = percent < 0 ? percent * -1 : percent;
    long R = f >> 16;
    long G = f >> 8 & 0x00FF;
    long B = f & 0x0000FF;
    int red = (int) (Math.round((t - R) * p) + R);
    int green = (int) (Math.round((t - G) * p) + G);
    int blue = (int) (Math.round((t - B) * p) + B);
    return Color.rgb(red, green, blue);
  }

  private final WeakReference<Activity> activityWeakReference;

  private final List<Shade> shades = new LinkedList<>();

  {
    shades.add(new Shade(0.9, "50"));
    shades.add(new Shade(0.7, "100"));
    shades.add(new Shade(0.5, "200"));
    shades.add(new Shade(0.333, "300"));
    shades.add(new Shade(0.166, "400"));
    shades.add(new Shade(0, "500"));
    shades.add(new Shade(-0.125, "600"));
    shades.add(new Shade(-0.25, "700"));
    shades.add(new Shade(-0.375, "800"));
    shades.add(new Shade(-0.5, "900"));
    shades.add(new Shade(0.7, "A100"));
    shades.add(new Shade(0.5, "A200"));
    shades.add(new Shade(0.166, "A400"));
    shades.add(new Shade(-0.25, "A700"));
  }

  public PaletteTask(Activity activity) {
    activityWeakReference = new WeakReference<>(activity);
  }

  @Override protected List<Shade> doInBackground(Integer... colors) {

    for (Shade shade : shades) {
      shade.color = shadeColor(colors[0], shade.percent);
    }

    return shades;
  }

  @Override protected void onPostExecute(List<Shade> shades) {
    Activity activity = activityWeakReference.get();
    if (activity == null || activity.isFinishing()) {
      return;
    }

    // Create a dialog that shows our generated colors:

    ScrollView scrollView = new ScrollView(activity);
    LinearLayout linearLayout = new LinearLayout(activity);
    linearLayout.setOrientation(LinearLayout.VERTICAL);

    int width, height;
    width = LinearLayout.LayoutParams.MATCH_PARENT;
    height = (int) (30/*dp*/ * (activity.getResources().getDisplayMetrics().densityDpi / 160f));

    // add each color
    for (Shade shade : shades) {
      LinearLayout layoutColor = new LinearLayout(activity);
      TextView textView = new TextView(activity);

      layoutColor.setLayoutParams(new LinearLayout.LayoutParams(width, height));
      layoutColor.setBackgroundColor(shade.color);
      layoutColor.setGravity(Gravity.CENTER);

      textView.setText(shade.name + "    " + String.format("#%06X", (0xFFFFFF & shade.color)));

      layoutColor.addView(textView);
      linearLayout.addView(layoutColor);
    }

    scrollView.addView(linearLayout);

    new AlertDialog.Builder(activity).setView(scrollView).show();
  }

  public static class Shade {

    final double percent;
    final String name;
    int color;

    public Shade(double percent, String name) {
      this.percent = percent;
      this.name = name;
    }
  }

}

Invoking the AsynTask:

int materialRed500 = 0xFFF44336;
new PaletteTask(this).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, materialRed500);

Dialog created from the above code: