如何设置android camera2预览和捕获大小？

Question

我正在使用SurfaceView 来显示我捕获的预览。我想使用 width=1080,height=1920 进行预览。在哪里可以设置预览的大小？

我搜索了一个答案，但它们都是针对相机版本一的。我正在使用 android.hardware.camera2。

private void takePreview() {
    try {
        final CaptureRequest.Builder previewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        previewRequestBuilder.addTarget(mSurfaceHolder.getSurface());
        mCameraDevice.createCaptureSession(Arrays.asList(mSurfaceHolder.getSurface(), mImageReader.getSurface()), new CameraCaptureSession.StateCallback() // ③
        {
            @Override
            public void onConfigured(CameraCaptureSession cameraCaptureSession) {
                if (null == mCameraDevice) return;
                mCameraCaptureSession = cameraCaptureSession;
                try {
                    previewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
                    previewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
                    previewRequestBuilder.set(CaptureRequest.JPEG_THUMBNAIL_SIZE, new Size(1080,1920));

                    CaptureRequest previewRequest = previewRequestBuilder.build();
                    mCameraCaptureSession.setRepeatingRequest(previewRequest, null, childHandler);
                } catch (CameraAccessException e) {
                    Log.e("takePreview","onConfigured(CameraCaptureSession cameraCaptureSession)",e);
                }
            }
            @Override
            public void onConfigureFailed(CameraCaptureSession cameraCaptureSession) {
                Log.e("takePreview","onConfigureFailed");
            }
        }, childHandler);
    } catch (CameraAccessException e) {
        Log.e("takePreview","CameraAccessException");
    }
}

Answer 1

如对createCaptureSession 的引用中所述：

绘制到SurfaceView：一旦创建了SurfaceView的Surface，用setFixedSize(int, int)将Surface的大小设置为getOutputSizes(SurfaceHolder.class返回的大小之一，然后通过调用getSurface()获取Surface。如果应用程序未设置尺寸，相机设备将舍入到最接近的小于 1080p 的支持尺寸。

Answer 2

看看 Google 在 GitHub 上提供的 Camera2Basic 示例：https://github.com/googlesamples/android-Camera2Basic

主片段中有一个方法可以为给定设备选择最佳预览尺寸。如果您想让您的应用更加灵活，而不是硬编码大小，这可能是一种更好的方法，但即使您仍然愿意坚持设置大小，您也可以看到它们如何使用结果。

总结是，您只需将 TextureView 的大小（在他们的情况下）设置为您想要的任何大小预览。

方法名称是“chooseOptimalSize”，其中包含以下注释/说明：

/**
     * Given {@code choices} of {@code Size}s supported by a camera, choose the smallest one that
     * is at least as large as the respective texture view size, and that is at most as large as the
     * respective max size, and whose aspect ratio matches with the specified value. If such size
     * doesn't exist, choose the largest one that is at most as large as the respective max size,
     * and whose aspect ratio matches with the specified value.
     *
     * @param choices           The list of sizes that the camera supports for the intended output
     *                          class
     * @param textureViewWidth  The width of the texture view relative to sensor coordinate
     * @param textureViewHeight The height of the texture view relative to sensor coordinate
     * @param maxWidth          The maximum width that can be chosen
     * @param maxHeight         The maximum height that can be chosen
     * @param aspectRatio       The aspect ratio
     * @return The optimal {@code Size}, or an arbitrary one if none were big enough
     */