CameraView/docs/_posts/2018-12-20-v1-migration-guide.md

layout	title	subtitle	category	date	order	disqus
page	v1 Migration Guide	Breaking Changes & new concepts	extra	2018-12-20 19:01:55	1	1

CameraView v2 introduces various breaking changes that will allow for more flexibility in the future, removes useless features and makes method names consistent. Upgrading will require addressing these in your app, plus understanding new concepts.

Until the final v2 release, these things might change, but likely they will not.

AndroidX

The lib was moved to AndroidX classes. Hopefully this should not have any impact on you.

Open, not start

The start() method has been renamed to open(), and the stop() method to close(). This was done for consistency with the onCameraOpened callback.

Jpeg Quality

Both cameraJpegQuality and setJpegQuality() have been removed. They were working only with specific setups and made no real sense. We will use the default quality provided by the camera engine.

Crop Output

Both cameraCropOutput and setCropOutput() have been removed. This was an expensive operation that worked with pictures only. In v2, if you want your output to be cropped to match the view bounds, you will use the *snapshot() APIs (see below).

Video Quality

This was an opaque option packaging various parameters. It has been removed. You are expected to control the video quality by choosing the video size and setting video parameters with new APIs (see below).

CameraUtils

• The BitmapCallback has been moved into a separate class.
• The BitmapCallback result is now @Nullable! This will happen if we encounter an OutOfMemoryError during decoding. You should consider passing a maxWidth and maxHeight instead of loading the full image.

CameraOptions

• Methods returning a Set now return a Collection instead.
• isVideoSnapshotSupported() was removed, as we do not rely on internal video snapshot feature anymore. See below.
• In addition to getSupportedPictureSizes and getSupportedPictureAspectRatio, we now have equivalent methods for video. See below.

Session type

The SessionType has been renamed to Mode which has a clearer meaning.

• setSessionType() is now setMode()
• cameraSessionType is now cameraMode

Sizing

• getPreviewSize() was removed.
• getPictureSize(): now returns the real output picture size. This means that it accounts for rotation. It will also return null while in VIDEO mode: use getVideoSize in that case.
• getVideoSize(): added. Returns the real output video size. This means that it accounts for rotation. It will return null while in PICTURE mode.
• getSnapshotSize(): This is the size of pictures taken with takePictureSnapshot() and videos taken with takeVideoSnapshot(). It accounts for rotation and cropping. Read about snapshots below.

As you might have guessed, video size is now configurable, with the addition of setVideoSize(SizeSelector) method. It works exactly like the picture one, so please refer to the size selector documentation. Defaults to SizeSelectors.biggest().

The engine will use the video size selector when mode is VIDEO, and the picture size selector when mode is PICTURE.

Picture and videos

Take, not capture

• capturePicture() is now takePicture()
• captureSnapshot() is now takePictureSnapshot()
• startCapturingVideo() is now takeVideo(). Signature changed from long to int
• isCapturingVideo() is now isTakingVideo()

The new isTakingPicture() method was added for symmetry with videos.

Snapshots

This is the major improvement over v1. There are now 4 capture APIs, two for pictures and two for videos.

• Standard APIs: takePicture() and takeVideo(). These take a high quality picture or video, depending on the SizeSelector and parameters that were used. The standard APIs must be called in the appropriate Mode (pictures must be taken in PICTURE mode, videos must be taken in VIDEO mode).
• Snapshot APIs: takePictureSnapshot() and takeVideoSnapshot(). These take a super fast, reliable snapshot of the camera preview. The snapshot APIs can be called in any Mode (you can snap videos in picture mode).

The good news is that snapshot APIs will automatically crop the result, for both video and pictures, which means that square videos or any other ratio are possible.

Method	Takes	Quality	Callable in Mode.PICTURE	Callable in Mode.VIDEO	Auto crop	Output size
takePicture()	Pictures	Standard	yes	no	no	That of setPictureSize
takeVideo()	Videos	Standard	no	yes	no	That of setVideoSize
takePictureSnapshot()	Pictures	Snapshot	yes	yes	yes	That of the view
takeVideoSnapshot()	Videos	Snapshot	yes	yes	yes	That of the view

The video snapshot supports audio and respects the Audio, max duration, max size & codec settings, which makes it a powerful tool. The drawback is that it needs:

• API 18. If called before, it throws
• An OpenGL preview (see below). If not, it throws

Video capturing

Some new APIs were introduced, which are respected by both standard videos and snapshot videos:

• setAudioBitRate() and cameraAudioBitRate: sets the audio bit rate in bit/s
• setVideoBitRate() and cameraVideoBitRate: sets the video bit rate in bit/s

Camera Preview

The type of preview is now configurable with cameraPreview XML attribute and Preview control class. This defaults to the new GL_SURFACE and it is highly recommended that you do not change this.

Preview	Backed by	Info
Preview.SURFACE	A SurfaceView	This might be better for battery, but will not work well (AFAIR) with dynamic layout changes and similar things. No support for video snapshots.
Preview.TEXTURE	A TextureView	Better. Requires hardware acceleration. No support for video snapshots.
Preview.GL_SURFACE	A GLSurfaceView	Supports video snapshots. Might support GL real time filters in the future.

The GL surface, as an extra benefit, has a much more efficient way of capturing picture snapshots, that avoids OOM errors, rotating the image on the fly, reading EXIF, and other horrible things belonging to v1. These picture snapshots will also work while taking videos.

Advanced feature: Preview Sizing

We finally introduced a setPreviewSize() method which accepts a SizeSelector. The use of this method is discouraged if you don't know exactly what you are doing. The default preview size selector is already smart enough to

• respect the picture/video aspect ratio
• be a bit bigger than the view so that there is no upscaling

There are not so many reason why you would use this method, other than, for example, control the frame processor size or, indirectly, the snapshots size. If what you are doing is just assigning an aspect ratio, for instance, please do so using setPictureSize() and setVideoSize().

Note: getPreviewSize() was removed as it has no useful meaning.

CameraListener

The listener interface brings two breaking signature changes:

• onPictureTaken() now returns a PictureResult. Use result.getJpeg() to access the jpeg stream. The result class includes rich information about the picture (or picture snapshot) that was taken, plus handy utilities (result.asBitmap()...)
• onVideoTaken() now returns a VideoResult. Use result.getFile() to access the video file. The result class includes rich information about the video (or video snapshot) that was taken.

Experimental mode

The v2 version introduces a cameraExperimental XML flag that you can use to enable experimental features. Might be used in the future to speed up development.

Other improvements & changes

• Added @Nullable and @NonNull annotations pretty much everywhere. This might break your Kotlin build.
• Added setGridColor() and cameraGridColor to control the grid color
• Default Facing value is not BACK anymore but rather a value that guarantees that you have cameras (if possible). If device has no BACK cameras, defaults to FRONT.
• Removed ExtraProperties as it was useless.

TODO: opencollective? TODO: improve the focus marker drawing, move out of XML (accept a drawable?)