I come up to you because I have a big problem.
I would like to capture only a portion of the camera view.
I basically want something like this :
I tried to do the same with AndroidStudio, by adding a picture on the screen, here is the result :
It's ugly but it was just to try.
You basically need to put your face into the transparent area, and then click on "take picture". I would like the camera to not take the black part.
How is it possible ? Is it possible to create a kind of mask for the camera ?
I have in mind that in this case, I'll need to take the entire picture and scale it correctly by software. But then, I have to do it differently for every screen sizes. It looks incredibly difficult.
Instead, is it possible to directly modify the cameraView (SurfaceView, or SurfaceHolder) so that I won't need the image, and the picture will automatically fit the "mask" because it's actually the only thing the camera see.
Have you got some clues ?
thank you very much !
The camera sees whatever enters its lens. You cannot "make" it see only a certain shape out of its normal rectangle (unless you tape some black paper over it :)). The cropping is always done after the picture is taken. The SurfaceView and SurfaceHolder are just tools to help you present the picture (which can be already modified, if you want it to) on the phone screen.
No you cannot mask camera capture. You can apply the mask to result. Note that often you get still picture at a resolution much higher than what you use for preview. And preview resolution is not the same as screen resolution (which you should use to put the black mask on the screen). In such case, your postprocessing mask should match the picture resolution and not the preview resolution.
Related
I want to display a preview in fullscreen using camera2 api. The camera size I selected is 4160x3120 (16:9) and my screen is 1080x1920 (9:16). Therefore if I want the preview to be right scaled I have to crop the camera output :
Rect zoomCrop = new Rect(0, 0, 1755, 3120);
captureRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, zoomCrop);
The cropped preview should be of size 1755x3120 which has a ratio of 9:16 as well. Still the preview is streched.
Question :
Am I using SCALER_CROP_REGION correctly ? If not, how am I supposed to use it ?
Thanks in advance
I've been struggling with the same sort of problem, as I want to implement a camera preview stream into a square TextureView.
Working with the SCALER_CROP_REGION seemed like the obvious place to resolve issues with incompatible aspect ratios, but I don't think that operation will ever actually change the aspect ratio of the result, hence it doesn't prevent stretching/warping behaviour. (the docs talk about this)
I've made progress by implementing a similar transform to the one in the Camera2Basic example project - see the function configureTransform in Camera2BasicFragment).
Using this sort of view-level scaling matrix, you can manage the scaling/cropping of the camera preview without altering the size of your view.
It sounds like you are getting a landscape image and displaying it in a portrait view - this means that you will have 'pillar box' lines above and below the image if you want to avoid distortion.
If you did want to fill the screen, and not have distortion or the pillar box lines then you would have to accept that part of your image will not be visible, as its outside the shape of the viewing area.
SCALER_CROP_REGION is tricky to understand without diagrams - I found the best explanation to be in the Andoir source documentation here: https://source.android.com/devices/camera/camera3_crop_reprocess
One diagram reproduced from that helps as an example here - the reason for highlight this is to show how the co-ordinates are being used. If you look at your crop region it will be biased towards the top left as you start at (0,0), which I am not sure is what you actually want.
i want to crop a image during capture not after capture.
like this image.
just replace save button with capture.
the rectangle should be realizable.just like the crop activity.
the thing i was doing was.
1st=capture image.
2nd=crop.
now i want to crop image during capture.
any help???
This is possible, Just think a different approach. Make a trick with camera preview. Taking a picture usually requires that your users see a preview of their subject before clicking the shutter. To do so, you can use a SurfaceView to draw previews of what the camera sensor is picking up. Now create a viewFinder for your camera capture activity. Now your make the compatible code to change the viewFinder size dynamically, which allow you to select the region. And finally save the Image from bitmap view inside ViewFinder. This is exactly what you want.
Please ask if you have not got my point. Best of luck.
My app is showing the camera preview on one of my activities. I would like to show the camera preview but not taking the full screen, just inside a small box.
The problem is that right now the image that i get from the camera is smaller that I want. For example, when I open it I can only see there my eyes and nose, but I would like to see my whole face.
It's like my surfeceView is acting like a window in a house that only allows me to see part of the views outside. The idea is that in the surfaceView (that does not take the whole screen space) I get the whole camera output but resized in order to fit the surfaceView.
Is that a problem with the camera preview size? Or should I somehow resize the camera output?
Thanks in advance
You should give us some code to find the problem, at least the layout.xml file and the class that uses SurfaceView and SurfaceHolder.Callbacks. For now, you can try the following if you didn't.
In the onSurfaceChanged method use the two int parameters width and height to calculate the best size for your preview. You do this with setPreviewSize and getSupportedPreviewSize.
If you can't fix the issue in an easy way you can also try to use an ImageView or a TextureView and paint on them the image that you are given from the onPreviewFrame callback.
I've always been under the impression that the preview and the final output are not connected in any way; meaning that I can set the preview to be some arbitrary dimension and that the final JPG will be whatever specific resolution I set in to be in the params, but I just ran into a very odd situation where the image data coming back in the byte[] that's in the jpg callback is different, depending on what dimensions I set my preview to.
Can someone enlighten me on what actual relationship the preview has on the final JPG? (or point me to documentation on said relationship).
TIA
[Edit]
As per ravi's answer, this was my assumption as well, however, I see no alternative but to surmise that they are, in fact, directly connected based on the evidence. I'll post code if necessary (though there's a lot of it) but here's what I'm doing.
I have a preview screen where the user takes a photo of themselves. I then display the picture captured (from the jpg callback bitmap data) in a subsequent draw view and allow them to trace a shape over their photo. I then pass the points of their polygon into a class that cuts that shape out of the original image, and gives back the cut image.
All of this works, BUT depending on how I present the PREVIEW, the polygon cutting class crashes on an array out of bounds index as it tries to access pixels on the final image that simply don't exist. This effect is produced EXCLUSIVELY by altering the shape of the preview View's dimensions. I'm not altering ANYTHING else in the code, and yet, just by mis-shaping my preview view, I can reproduce this error 100% of the time.
I can't see an explanation other than that the preview and the final are directly connected somehow, since I'm never operating on the preview's data, I only display it in a SurfaceView and then move on to deal exclusively with the data from the JPG callback following the user having taken their photo.
There is no relation between the preview resolution and the final image that is captured.
They are completely independent (at least for the still image capture). The preview resolution and the aspect ratio are not interrelated with the final image resolution and the aspect ratio in anyway.
In the camera application that I have written, the preview is always VGA but the image I capture varies from 5M to VGA (depending on the device capability)
Perhaps if you can explain the situation it would be more helpful.
We are currently developing a camera application and face very similiar problems. In our case, we want to display a 16:9 preview, while capturing a 4:3 picture. On most devices this works without any problems, but on some (e.g. Galaxy Nexus, LG Optimus 3D), the output camera picture depends on the preview you've chosen. In our case the outcoming pictures on that devices are distorted when the preview ratio is different from the picture ratio.
We tried to fix this, by changing the preview resolution to a better one just before capturing the image. But this does not work on some devices and occure error while starting the preview again after capturing is finished.
We also tried to fix this, by enlarging the SurfaceView to fullscreen-width and "over fullscreen"-height to make a 16:9 preview out of a 4:3 preview. But this does not work, because SurfaceViews can not be higher then screenheight.
So there IS any connection on SOME devices, and we really want to know, how to fix/workaround this.
I need a little help with getting my camera to work right.
What I'm trying to do is have the user take a picture that will then be used in another activity as the view's background. It is important not to have any skewing, and ideally the image would fill the entire background with the highest resolution possible.
I've been having a heck of a time trying to get the outputted picture of my camera to be oriented properly and be the same aspect of the display. So I took some time to think of exactly what I needed to do, and I don't think I need the normal saved image at all.
What I came up with is that I need a surface view to display the preview, and an overlay for some text and a capture button. When the user "takes the picture" it should autofocus, and then I need to capture the preview (under the screen overlays) to a bitmap to use in the other activity.
*Should I extend a SurfaceView for my preview and add it to a XML layout that contains the overlays?
*How do I save the SurfaceView's image to a bitmap?
Thanks.
Matt,
One basic question ,and excuse my naivety, wouldnt it just be easier to use the built in camera to the Android through an Intent? It is doable, I've done it before.
Apparently, there is no good way to convert the image format of the preview frames to a jpeg, so I ended up selecting the size for the camera to take by going through each of the camera's supported resolutions and getting the closest match the the screen aspect with the highest resolution.
Because the camera.setRotation method doesn't seem to do anything, I just rotate the image 90 with a matrix before saving it to the card if I am in portrait mode.