Android Picasso实现圆形图片和圆角图片

// 定义一个自定义的Transformation
public class CircleTransform implements Transformation {
    @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);
        Paint paint = new Paint();
        BitmapShader shader = new BitmapShader(squaredBitmap, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP);
        paint.setShader(shader);
        paint.setAntiAlias(true);

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

        squaredBitmap.recycle();
        return bitmap;
    }

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

// 使用Picasso加载并显示圆形图片
Picasso.get()
    .load(imageUrl)
    .transform(new CircleTransform())
    .into(imageView);

// 定义一个自定义的Transformation
public class RoundedCornersTransform implements Transformation {
    private final int radius;

    public RoundedCornersTransform(int radius) {
        this.radius = radius;
    }

    @Override
    public Bitmap transform(Bitmap source) {
        Bitmap result = Bitmap.createBitmap(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(result);

        Paint paint = new Paint();
        paint.setAntiAlias(true);
        paint.setColor(Color.WHITE);

        RectF rectF = new RectF(0, 0, source.getWidth(), source.getHeight());
        canvas.drawRoundRect(rectF, radius, radius, paint);

        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(source, 0, 0, paint);

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

        return result;
    }

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

// 使用Picasso加载并显示圆角图片
Picasso.get()
    .load(imageUrl)
    .transform(new RoundedCornersTransform(radius))
    .into(imageView);