Linear gradient and bitmap shader not playing well

Question

I'm trying to create a "Transform" for the Android library Picasso. The problem (I think) though is more generic to how ComposeShaders work.

I'm trying to achieve a straightforward vertical linear gradient applied on top of the image, using Bitmap shaders. Here's the code:

@Override
public Bitmap transform(Bitmap source) {

    Bitmap bitmap = Bitmap.createBitmap(source.getWidth(),
                                        source.getHeight(),
                                        source.getConfig());

    shaders[0] = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
    shaders[1] = new LinearGradient(0,
                                    0,
                                    0,
                                    source.getHeight(),
                                    Color.BLACK,
                                    Color.TRANSPARENT,
                                    Shader.TileMode.CLAMP);
    ComposeShader composeShader = new ComposeShader(shaders[0],
                                                    shaders[1],
                                                    PorterDuff.Mode.DST_IN);

    Paint paint = new Paint();
    paint.setAntiAlias(true);
    paint.setShader(composeShader);

    Canvas canvas = new Canvas(bitmap);
    canvas.drawPaint(paint);

    source.recycle();
    return bitmap;
}

When running the tranformation, I get the nice vertical gradient, but the Bitmap is not seen at all. So i basically only get a vertical gradient. Help?

Other relevant code:

    Picasso.with(getActivity())
           .load(myValidUrl)
           .transform(new TopVignetteTransformation())
           .into(myImageview);


<ImageView
    android:background="@color/dark_gray"
    android:scaleType="centerCrop"
    android:adjustViewBounds="true"
    android:layout_height="match_parent"
    android:layout_width="match_parent"/>

Answer 1

Arrgh. Stupid typo. Sourcing the wrong bitmap for the Bitmap shader

shaders[0] = new BitmapShader(source, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);