需要在Android中使用相机捕获矩形视图内的图像

我正在android中创建一个文档扫描应用程序,正在我的项目中使用OpenCV和扫描库进行裁剪,我已经在相机视图中使用drawrect创建了一个矩形,现在我只需要捕获该矩形部分内的图像并在另一个活动中显示它.

有问题的图片：

解决方法:

对我来说,我将拍摄整个图像,然后进行裁剪.
您的问题是：“我怎么知道图像的哪个部分在矩形部分内,那么只有我能通过它,希望您能理解”.我的答案是您可以使用整个图像尺寸和相机显示屏尺寸的相对缩放.然后,您将知道要裁剪矩形的哪一部分.

这是代码示例.
请注意,您需要填写一些代码以使其可以将文件保存为jpg,并在裁剪后保存.

    // 1. Save your bitmap to file
    public class MyPictureCallback implements Camera.PictureCallback  {
    @Override
    public void onPictureTaken(byte[] data, Camera camera) {

        try {
            //mPictureFile is a file to save the captured image
            FileOutputStream fos = new FileOutputStream(mPictureFile);
            fos.write(data);
            fos.close();

        } catch (FileNotFoundException e) {
            Log.d(TAG, "File not found: " + e.getMessage());
        }
    }
    }

    // Somewhere in your code
    // 2.1 Load bitmap from your .jpg file              
    Bitmap bitmap = BitmapFactory.decodeFile(path+"/mPictureFile_name.jpg");

    // 2.2 Rotate the bitmap to be the same as display, if need.
    ... Add some bitmap rotate code

    // 2.3 Size of rotated bitmap
    int bitWidth = bitmap.getWidth();
    int bitHeight = bitmap.getHeight();

    // 3. Size of camera preview on screen  
    int preWidth = preview.getWidth();
    int preHeight = preview.getHeight();

    // 4. Scale it. 
    // Assume you draw Rect as "canvas.drawRect(60, 50, 210, 297, paint);" command
    int startx = 60 * bitWidth / preWidth;
    int starty = 50 * bitHeight / preHeight;
    int endx = 210 * bitWidth / preWidth;
    int endy = 297 * bitHeight / preHeight;

    // 5. Crop image
    Bitmap blueArea = Bitmap.createBitmap(bitmap, startx, starty, endx, endy);

    // 6. Save Crop bitmap to file

标签：opencv,android-camera,android
来源： https://codeday.me/bug/20191118/2031432.html