Need to capture images inside the rectangular view using camera in android

Question

Am creating a document scanning application in android, am using OpenCV and Scan library in my project for cropping,I have created a rectangle using drawrect in camera view, now I need to capture the images inside that rectangle portion only and display it in another activity.

The image in question:

u can take the normal image from the camera and later draw it in a canvas crop the part that are in outer rectangle — Preethi Rao, Mar 31 '16 at 09:34
@Preethi Rao but actually I need to pass the image inside the rectangular view how I can pass that image portion only — balajivaishnav, Mar 31 '16 at 09:36
i dont know purpose of passing image inside rectangular view from the image what i saw u can draw a rectangle over the canvas and draw image in the same canvas and crop unwanted portions — Preethi Rao, Mar 31 '16 at 09:39
but how do I know which part of the image is inside the rectangular portion, then only I can pass it nah, hope u understood — balajivaishnav, Mar 31 '16 at 09:43
@M Balajivaishnav, i am also trying document scanner what you did it. Could you please share the code?.. — user, Jul 02 '18 at 13:24
i need to scan the document, while open surfaceview(camera) i need to display with frame with size of a4 sheet, and take picture and crop the image automatically the size of as sheet. — user, Jul 02 '18 at 13:54

ปรีดา ตั้งนภากร · Accepted Answer · 2016-04-01T14:36:24.633

5

For me , I will take whole image, then crop. Your question : "how do I know which part of the image is inside the rectangular portion, then only I can pass it nah, hope u understood". My answer is you can using relativity scaling of whole image dimension and camera display screen dimension. Then you will know which part of rectangular to be cropped.

This is the code example. Note that you need to fill some codes to make it can save file into jpg, and save it after cropped.

    // 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

edited Apr 01 '16 at 14:36

answered Mar 31 '16 at 10:13

ปรีดา ตั้งนภากร

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can u give me some link or code snippet to undersatnd – balajivaishnav Mar 31 '16 at 10:19
@M Balajivaishnav . Show me your code to draw rectangular on the camara view. I will add the necessary part to make it work. – ปรีดา ตั้งนภากร Mar 31 '16 at 10:26
can I paste it in paste bin link – balajivaishnav Mar 31 '16 at 10:33
do u know the solution for it – balajivaishnav Mar 31 '16 at 12:53
can u tell me what is preview I think its not declared any where – balajivaishnav Mar 31 '16 at 15:18
preview is defined in your code. I use it to get size in pixel of your surfaceview -- > preview = new Preview(this,(SurfaceView) findViewById(R.id.KutCameraFragment)); – ปรีดา ตั้งนภากร Mar 31 '16 at 16:32
1

Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/107912/discussion-between---and-m-balajivaishnav). – ปรีดา ตั้งนภากร Apr 01 '16 at 02:19
Finally worked after changing some codes, thank you your code made me to understand the logic behind it – balajivaishnav Apr 01 '16 at 13:01
@ปรีดาตั้งนภากร do u know how to crop exact images after capturing it, like cam scanner, office lens application are doing it, have any idea on that – balajivaishnav Apr 06 '16 at 07:24
@M Balajivaishnav. No, I do not. – ปรีดา ตั้งนภากร Apr 06 '16 at 11:14
@balajivaishnav did you found any exact solution for this? I mean clicking pics like cam scanner? – Cosmic Dev May 12 '20 at 02:04
Yes I have sorted it out – balajivaishnav May 12 '20 at 20:58

score -1 · Answer 2 · edited May 23 '17 at 12:31

-1

This will work for you: How to programmatically take a screenshot in Android?

Make sure that the view (v1 in the code sample's case) passed in Bitmap.createBitmap(v1.getDrawingCache()) is a viewgroup that contains the image you want ot send to the second activity

Edit: I don't think your intended flow is feasible. As far as I know, camera intents don't take arguments allowing to draw such a rectangle (I could be wrong though).

Instead, I suggest you take a picture, and then edit it with a library such as this one (https://github.com/ArthurHub/Android-Image-Cropper) or programatically as suggested above.

edited May 23 '17 at 12:31

Community

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answered Mar 31 '16 at 09:29

Bruno Carrier

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taking screen shot huh ? but I need to capture from the camera, please see the link – balajivaishnav Mar 31 '16 at 09:32
It will take 2 steps instead of 1 step, so I think it is not good for UX – HendraWD Apr 02 '19 at 08:47

Need to capture images inside the rectangular view using camera in android

2 Answers2