CameraView/docs/_posts/2018-12-20-capture-size.md

layout	title	subtitle	category	order	date	disqus
page	Capture Size	Set size of output media	docs	8	2018-12-20 22:07:22	1

If you are planning to use the snapshot APIs, the size of the media output is that of the preview, accounting for any cropping made when measuring the view. If you are planning to use the standard APIs for capturing, then what follows applies.

Controlling Size

Size is controlled using setPictureSize and setVideoSize for, respectively, picture and video output. These method will accept a SizeSelector. The point of a SizeSelector is to analyze the available sizes that the sensor offers, and choose the ones it prefers.

// This will be the size of pictures taken with takePicture().
cameraView.setPictureSize(new SizeSelector() {
    @Override
    public List<Size> select(List<Size> source) {
        // Receives a list of available sizes.
        // Must return a list of acceptable sizes.
    }
});

// This will be the size of videos taken with takeVideo().
cameraView.setVideoSize(new SizeSelector() {
    @Override
    public List<Size> select(List<Size> source) {
        // Same here.
    }
});

In practice, this is way easier using XML attributes or leveraging the SizeSelectors utilities.

XML attributes

<com.otaliastudios.cameraview.CameraView
    app:cameraPictureSizeMinWidth="100"
    app:cameraPictureSizeMinHeight="100"
    app:cameraPictureSizeMaxWidth="3000"
    app:cameraPictureSizeMaxHeight="3000"
    app:cameraPictureSizeMinArea="10000000"
    app:cameraPictureSizeMaxArea="50000000"
    app:cameraPictureSizeAspectRatio="1:1"
    app:cameraPictureSizeSmallest="true|false"
    app:cameraPictureSizeBiggest="true|false"
    
    app:cameraVideoSizeMinWidth="100"
    app:cameraVideoSizeMinHeight="100"
    app:cameraVideoSizeMaxWidth="3000"
    app:cameraVideoSizeMaxHeight="3000"
    app:cameraVideoSizeMinArea="10000000"
    app:cameraVideoSizeMaxArea="50000000"
    app:cameraVideoSizeAspectRatio="1:1"
    app:cameraVideoSizeSmallest="true|false"
    app:cameraVideoSizeBiggest="true|false"
    />

The cameraPicture* attributes are used in picture mode, while the cameraVideo* attributes are used in video mode. Note that, for each mode, if you declare more than one XML constraint, the resulting selector will try to match all the constraints. Be careful - it is very likely that applying lots of constraints will give empty results.

SizeSelectors utilities

All these XML attrs are actually shorthands to some SizeSelectors utility method. For more versatility, or to address selection issues with multiple constraints, we encourage you to use SizeSelectors to get a selector, and then apply it to the CameraView as seen.

The utilities will even let you merge different selectors with or or and logic, in a very intuitive way. For example:

SizeSelector width = SizeSelectors.minWidth(1000);
SizeSelector height = SizeSelectors.minHeight(2000);
SizeSelector dimensions = SizeSelectors.and(width, height); // Matches sizes bigger than 1000x2000.
SizeSelector ratio = SizeSelectors.aspectRatio(AspectRatio.of(1, 1), 0); // Matches 1:1 sizes.

SizeSelector result = SizeSelectors.or(
    SizeSelectors.and(ratio, dimensions), // Try to match both constraints
    ratio, // If none is found, at least try to match the aspect ratio
    SizeSelectors.biggest() // If none is found, take the biggest
);
camera.setPictureSize(result);
camera.setVideoSize(result);

This selector will try to find square sizes bigger than 1000x2000. If none is found, it falls back to just square sizes.

Related APIs

Method	Description
setPictureSize(SizeSelector)	Provides a size selector for the capture size in PICTURE mode.
setVideoSize(SizeSelector)	Provides a size selector for the capture size in VIDEO mode.
getPictureSize()	Returns the size of the output picture, including any rotation. Returns null in VIDEO mode.
getVideoSize()	Returns the size of the output video, including any rotation. Returns null in PICTURE mode.