update readme

README.md

@@ -2,24 +2,85 @@
 
 A react native vision camera frame processor for cropping
 
+[Demo video](https://github.com/tony-xlh/vision-camera-cropper/assets/5462205/81031752-4179-4439-a8c6-97f73587fd56)
+
+
+## Versions
+
+For Vision Camera v3, use versions 0.x.
+
+For Vision Camera v4, use versions >= 1.0.0.
+
 ## Installation
 
 ```sh
-npm install vision-camera-cropper
+yarn add vision-camera-cropper
+cd ios && pod install
 ```
 
+Add the plugin to your `babel.config.js`:
+
+```js
+module.exports = {
+   plugins: [['react-native-worklets-core/plugin']],
+    // ...
+```
+
+> Note: You have to restart metro-bundler for changes in the `babel.config.js` file to take effect.
+
 ## Usage
 
+1. Crop a frame and return its base64 or path.
+      
+    ```js
+    import { crop } from 'vision-camera-cropper';
 
-```js
-import { multiply } from 'vision-camera-cropper';
+    // ...
+    const frameProcessor = useFrameProcessor((frame) => {
+      'worklet';
+      //coordinates in percentage
+      const cropRegion = {
+        left:10,
+        top:10,
+        width:80,
+        height:30
+      }
+      const result = crop(frame,{cropRegion:cropRegion,includeImageBase64:true,saveAsFile:false});
+      console.log(result.base64);
+    }, []);
+    ```
+
+2. Rotate an image.
+
+    ```js
+    const rotated = await rotateImage(base64,degree);
+    ```
+
+## Get Bitmap/UIImage via Reflection
+
+If you are developing a plugin to get the camera frames, you can use reflection to get it as Bitmap or UIImage on the native side.
 
-// ...
+Java:
 
-const result = await multiply(3, 7);
+```java
+Class cls = Class.forName("com.visioncameracropper.CropperFrameProcessorPlugin");
+Method m = cls.getMethod("getBitmap",null);
+Bitmap bitmap = (Bitmap) m.invoke(null, null);
 ```
 
 
+Objective-C:
+
+```objc
+- (UIImage*)getUIImage{
+    UIImage *image = ((UIImage* (*)(id, SEL))objc_msgSend)(objc_getClass("CropperFrameProcessorPlugin"), sel_registerName("getBitmap"));
+    return image;
+}
+```
+
+You have to pass `{saveBitmap: true}` for the `crop` function.
+
+
 ## Contributing
 
 See the [contributing guide](CONTRIBUTING.md) to learn how to contribute to the repository and the development workflow.