圓形化身與 Picasso

這是一個基於原始的 Picasso Circle Transform 類的示例，新增了一個細邊框，還包括用於堆疊的可選分隔符的功能：

import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;

import com.squareup.picasso.Transformation;

public class CircleTransform implements Transformation {

    boolean mCircleSeparator = false;

    public CircleTransform(){
    }

    public CircleTransform(boolean circleSeparator){
        mCircleSeparator = circleSeparator;
    }

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

        int x = (source.getWidth() - size) / 2;
        int y = (source.getHeight() - size) / 2;

        Bitmap squaredBitmap = Bitmap.createBitmap(source, x, y, size, size);

        if (squaredBitmap != source) {
            source.recycle();
        }

        Bitmap bitmap = Bitmap.createBitmap(size, size, source.getConfig());

        Canvas canvas = new Canvas(bitmap);
        BitmapShader shader = new BitmapShader(squaredBitmap, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP);
        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG | Paint.FILTER_BITMAP_FLAG);
        paint.setShader(shader);

        float r = size/2f;
        canvas.drawCircle(r, r, r-1, paint);

        // Make the thin border:
        Paint paintBorder = new Paint();
        paintBorder.setStyle(Style.STROKE);
        paintBorder.setColor(Color.argb(84,0,0,0));
        paintBorder.setAntiAlias(true);
        paintBorder.setStrokeWidth(1);
        canvas.drawCircle(r, r, r-1, paintBorder);

        // Optional separator for stacking:
        if (mCircleSeparator) {
            Paint paintBorderSeparator = new Paint();
            paintBorderSeparator.setStyle(Style.STROKE);
            paintBorderSeparator.setColor(Color.parseColor("#ffffff"));
            paintBorderSeparator.setAntiAlias(true);
            paintBorderSeparator.setStrokeWidth(4);
            canvas.drawCircle(r, r, r+1, paintBorderSeparator);
        }

        squaredBitmap.recycle();
        return bitmap;
    }

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

以下是載入影象時如何使用它（假設 this 是一個活動上下文，url 是一個帶有要載入的影象的 url 的 String）：

ImageView ivAvatar = (ImageView) itemView.findViewById(R.id.avatar);
Picasso.with(this).load(url)
    .fit()
    .transform(new CircleTransform())
    .into(ivAvatar);

結果：

要與分隔符一起使用，請將 true 提供給頂部影象的建構函式：

ImageView ivAvatar = (ImageView) itemView.findViewById(R.id.avatar);
Picasso.with(this).load(url)
    .fit()
    .transform(new CircleTransform(true))
    .into(ivAvatar);

結果（FrameLayout 中的兩個 ImageView）：