PaletteTransformation.java

package co.touchlab.droidconandroid.utils;
import android.graphics.Bitmap;
import android.support.v7.graphics.Palette;

import com.squareup.picasso.Transformation;

import java.util.Map;
import java.util.WeakHashMap;

/**
 * Created by izzyoji :) on 7/30/15.
 */
public final class PaletteTransformation implements Transformation
{
    private static final PaletteTransformation INSTANCE = new PaletteTransformation();
    private static final Map<Bitmap, Palette>  CACHE    = new WeakHashMap<>();

    public static PaletteTransformation instance()
    {
        return INSTANCE;
    }

    public static Palette getPalette(Bitmap bitmap)
    {
        return CACHE.get(bitmap);
    }

    private PaletteTransformation()
    {
    }

    @Override
    public Bitmap transform(Bitmap source)
    {
        Palette palette = Palette.from(source).generate();
        CACHE.put(source, palette);
        return source;
    }

    @Override
    public String key()
    {
        return null;
    }

    // ...
}