Gradient Transformation For Picasso

GradientTransformation.java

/**
 * Created by Miao1007 on 2/2/15.
 *
 * Original Code: https://gist.github.com/miao1007/3f7e9b5f011fc188eba6
 */
 
public class GradientTransformation implements Transformation {

  int startColor = Color.argb(240,0,0,0);
  int endColor = Color.TRANSPARENT;

  @Override public Bitmap transform(Bitmap source) {

    int x = source.getWidth();
    int y = source.getHeight();

    Bitmap grandientBitmap = source.copy(source.getConfig(), true);
    Canvas canvas = new Canvas(grandientBitmap);
    //left-top == (0,0) , right-bottom(x,y);
    LinearGradient grad =
        new LinearGradient(x/2, y, x/2, y/2, startColor, endColor, Shader.TileMode.CLAMP);
    Paint p = new Paint(Paint.DITHER_FLAG);
    p.setShader(null);
    p.setDither(true);
    p.setFilterBitmap(true);
    p.setShader(grad);
    canvas.drawPaint(p);
    source.recycle();
    return grandientBitmap;
  }

  @Override public String key() {
    return "Gradient";
  }
}

Usage in imageview

  
Picasso.with(context)
    .load(url)
    .transform(new GradientTransformation())
    .into(imageview);

This gradient color is not smooth

This is good one, thanks! :)