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I'm running into an issue with camera input in Android. After searching over the internet for half a day I'm not getting any further.

Wat I want to achieve at this stage is correctly displaying the current camera input. Nothing more and nothing less for now. When holding the device in landscape mode, all seems fine. However as soon as I switch the device to portrait the display seems to be horizontally scaled in order to match the width of the screen on the device.

In order to clarify this issue a bit more, I've attached two photographs:

It seems like this issue also occurs with the camera example from the API examples, but it doesn't seem to occur when I use the camera application from my device. So clearly something else is happening there.

The code that I'm using is based on examples that can be found over the internet and has no modifications:

class Preview extends SurfaceView implements SurfaceHolder.Callback {
    SurfaceHolder mHolder;
    Camera mCamera;

    Preview(Context context) {
        super(context);
        mHolder = getHolder();
        mHolder.addCallback(this);
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        mCamera = Camera.open();
        try {
            mCamera.setPreviewDisplay(holder);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        mCamera.stopPreview();
        mCamera = null;
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        Camera.Parameters parameters = mCamera.getParameters();
        parameters.setPreviewSize(w, h);
        mCamera.setParameters(parameters);
        mCamera.startPreview();
    }
}

The API examples make use of a method "getOptimalPreviewSize(...)" which sounds like the method I need, but that does not change anything. I left it out here in order to be as brief as possible.

Am I missing something obvious or is this the expected behavior?

Hopefully someone can point me in the correct direction.

Thanks in advance!

Paul

PaulT
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  • The effect of distortion gets a little bit lost in the attached images. But on the landscape image the computer screen looks widescreen. On the portrait image it looks like a square screen. – PaulT Jul 15 '11 at 17:00
  • what is the preview resolution you are setting? – bluefalcon Jul 15 '11 at 17:26
  • The resolution depends on the device. In this case it is 1024 x 524 on the Galaxy tab. – PaulT Jul 15 '11 at 19:07
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    Ok, found the answer myself, but unfortunately I am not allowed to answer my own question as a newbie and I need to wait 5 hours to post the full answer. But what did the trick was the following: requestWindowFeature(Window.FEATURE_NO_TITLE); Will post the full motivation as soon as I am allowed to. – PaulT Jul 15 '11 at 19:56
  • Hi, did u had this problem also: http://stackoverflow.com/questions/16727836/camera-display-preview-in-full-screen-does-not-maintain-aspect-ratio-image-i/16733405 ? thanks – Paul May 27 '13 at 06:53

1 Answers1

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Okay, I just found the answer to my own question. The way I solved it was by going fullscreen with my application:

requestWindowFeature(Window.FEATURE_NO_TITLE);

This makes a little bit of sense, as I guess we can not use just any resolution as the preview size on the camera. I guess it will internally snap to the closest allowed resolution/aspect ratio and it doesn't do any smart things like cropping the image to match the requested resolution while maintaining aspect ratio. In my case I was displaying a title bar while the source image was fullscreen and then downsized to fit on the screen.

I think it is kind of stupid that the aspect ratio is not maintained and images are not cropped by default,

PaulT
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  • yeah, I have come to the same conclusion now. Not sure why the camera would not respect the aspect ration coz you want to see how things look via the camera. – Prakash Nadar Jan 19 '12 at 21:29