package jp.wasabeef.picasso.transformations;

/**
 * Copyright (C) 2015 Wasabeef
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import com.squareup.picasso.Transformation;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.RectF;

public class CropTopTransformation implements Transformation {

    private int mWidth;
    private int mHeight;

    public CropTopTransformation() {
    }

    public CropTopTransformation(int width, int height) {
        mWidth = width;
        mHeight = height;
    }

    @Override
    public Bitmap transform(Bitmap source) {
        if (mWidth == 0) {
            mWidth = source.getWidth();
        }
        if (mHeight == 0) {
            mHeight = source.getHeight();
        }

        float scaleX = (float) mWidth / source.getWidth();
        float scaleY = (float) mHeight / source.getHeight();
        float scale = Math.max(scaleX, scaleY);

        float scaledWidth = scale * source.getWidth();
        float scaledHeight = scale * source.getHeight();
        float left = (mWidth - scaledWidth) / 2;
        float top = 0;
        RectF targetRect = new RectF(left, top, left + scaledWidth, top + scaledHeight);

        Bitmap bitmap = Bitmap.createBitmap(mWidth, mHeight, source.getConfig());
        Canvas canvas = new Canvas(bitmap);
        canvas.drawBitmap(source, null, targetRect, null);
        source.recycle();

        return bitmap;
    }

    @Override
    public String key() {
        return "CropTopTransformation(width=" + mWidth + ", height=" + mHeight + ")";
    }
}

Create CropTopTransformation.java