CropCircleTransformation.java

package io.github.droidkaigi.confsched.widget.transformation;

import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;

import com.squareup.picasso.Transformation;

public class CropCircleTransformation implements Transformation {

    @Override
    public Bitmap transform(Bitmap source) {
        int size = Math.min(source.getWidth(), source.getHeight());

        int width = (source.getWidth() - size) / 2;
        int height = (source.getHeight() - size) / 2;

        Bitmap bitmap = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_4444);

        Canvas canvas = new Canvas(bitmap);
        Paint paint = new Paint();
        BitmapShader shader =
                new BitmapShader(source, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP);
        if (width != 0 || height != 0) {
            // source isn't square, move viewport to center
            Matrix matrix = new Matrix();
            matrix.setTranslate(-width, -height);
            shader.setLocalMatrix(matrix);
        }
        paint.setShader(shader);
        paint.setAntiAlias(true);

        float r = size / 2f;
        canvas.drawCircle(r, r, r, paint);

        source.recycle();

        return bitmap;
    }

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

}