Android - 保证图片以高为标准，做宽高比同比例拉伸

/**
 * 保证图片以高为标准，做宽高比同比例拉伸
 */
private void handleImageView() {
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    decodeResource(getContext().getResources(), R.mipmap.preview_bg_window, options);
}

private Bitmap decodeResource(Resources resources, int id, BitmapFactory.Options opts) {
    TypedValue value = new TypedValue();
    resources.openRawResource(id, value);
    opts.inTargetDensity = value.density;
    return BitmapFactory.decodeResource(resources, id, opts);
}