Android app拍照后给图片加水印大小随着图片大小固定比例 具体代码

以下是一个简单的示例代码，可以在 Android 应用程序中拍照并添加水印。其中水印的大小随着图片大小固定比例，具体代码如下：

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_IMAGE_CAPTURE = 1;
    private ImageView mImageView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mImageView = findViewById(R.id.image_view);

        Button btnCamera = findViewById(R.id.btn_camera);
        btnCamera.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dispatchTakePictureIntent();
            }
        });
    }

    private void dispatchTakePictureIntent() {
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
            startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
            Bundle extras = data.getExtras();
            Bitmap imageBitmap = (Bitmap) extras.get("data");

            Bitmap watermarkedBitmap = addWatermark(imageBitmap);

            mImageView.setImageBitmap(watermarkedBitmap);
        }
    }

    private Bitmap addWatermark(Bitmap source) {
        int w = source.getWidth();
        int h = source.getHeight();
        Bitmap result = Bitmap.createBitmap(w, h, source.getConfig());

        Canvas canvas = new Canvas(result);
        canvas.drawBitmap(source, 0, 0, null);

        // 设置水印图片
        Bitmap watermark = BitmapFactory.decodeResource(getResources(), R.drawable.watermark);

        // 计算水印大小
        int watermarkWidth = (int) (w * 0.3);
        int watermarkHeight = (int) (watermarkWidth * watermark.getHeight() / watermark.getWidth());

        // 缩放水印图片
        watermark = Bitmap.createScaledBitmap(watermark, watermarkWidth, watermarkHeight, false);

        // 添加水印
        canvas.drawBitmap(watermark, w - watermarkWidth - 10, h - watermarkHeight - 10, null);

        return result;
    }
}

在这个示例中，当用户点击“拍照”按钮时，调用 `dispatchTakePictureIntent()` 方法启动系统相机应用程序，用户拍照后将得到的图片作为返回值传递回来。然后，我们调用 `addWatermark()` 方法向图像中添加水印。在这个方法中，我们可以先计算出水印的大小，然后缩放水印图片并将其添加到图片的右下角。最后，我们返回一个包含水印的新位图。