Android Camera 2 预览尺寸和设备纵横比

Question

我正在我的项目中实现 Camera 2 API。 我正在使用 TextureView 和这些代码行来设置相机全屏预览大小：

StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
                mPreviewSize = map.getOutputSizes(SurfaceTexture.class)[0];

这似乎是设备支持的最大预览尺寸。 我不确定这个尺寸是否适用于所有设备并适合其设备的纵横比而不会被拉伸。 有人知道吗？

Answer 1

如果您的相机分辨率、纹理视图和您设备的显示尺寸不同，那么您必须调整尺寸。 为此，您必须将TextureView 放在 FrameLayout 内。 下面的代码适用于具有各种显示分辨率的所有设备。

如果您在全屏预览，请使用您的显示尺寸。使用int DSI_height , int DSI_width全局变量。

    DisplayMetrics displayMetrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
    DSI_height = displayMetrics.heightPixels;
    DSI_width = displayMetrics.widthPixels;

从 Camera2 API 中选择您需要的分辨率并分配给Size imageDimension ，全局获取private Size imageDimension并使用

setAspectRatioTextureView(imageDimension.getHeight(),imageDimension.getWidth());

并使用以下逻辑

private void setAspectRatioTextureView(int ResolutionWidth , int ResolutionHeight )
    {
        if(ResolutionWidth > ResolutionHeight){
            int newWidth = DSI_width;
            int newHeight = ((DSI_width * ResolutionWidth)/ResolutionHeight);
            updateTextureViewSize(newWidth,newHeight);

        }else {
            int newWidth = DSI_width;
            int newHeight = ((DSI_width * ResolutionHeight)/ResolutionWidth);
            updateTextureViewSize(newWidth,newHeight);
        }

    }

    private void updateTextureViewSize(int viewWidth, int viewHeight) {
        Log.d(TAG, "TextureView Width : " + viewWidth + " TextureView Height : " + viewHeight);
        textureView.setLayoutParams(new FrameLayout.LayoutParams(viewWidth, viewHeight));
    }

Answer 2

可能存在这种方法会失败的边缘情况，但对于您的问题为什么我没有完美的答案。

相比之下，我有一个正确的方法来说明如何实现一个肯定会起作用的版本：

查看Camera 2的Google API 演示，我发现了一些示例代码，它们应该对您有帮助，以确保它适合所有屏幕尺寸正确：

/**
 * 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
 */
private static Size chooseOptimalSize(Size[] choices, int textureViewWidth,
        int textureViewHeight, int maxWidth, int maxHeight, Size aspectRatio) {

    // Collect the supported resolutions that are at least as big as the preview Surface
    List<Size> bigEnough = new ArrayList<>();
    // Collect the supported resolutions that are smaller than the preview Surface
    List<Size> notBigEnough = new ArrayList<>();
    int w = aspectRatio.getWidth();
    int h = aspectRatio.getHeight();
    for (Size option : choices) {
        if (option.getWidth() <= maxWidth && option.getHeight() <= maxHeight &&
                option.getHeight() == option.getWidth() * h / w) {
            if (option.getWidth() >= textureViewWidth &&
                option.getHeight() >= textureViewHeight) {
                bigEnough.add(option);
            } else {
                notBigEnough.add(option);
            }
        }
    }

    // Pick the smallest of those big enough. If there is no one big enough, pick the
    // largest of those not big enough.
    if (bigEnough.size() > 0) {
        return Collections.min(bigEnough, new CompareSizesByArea());
    } else if (notBigEnough.size() > 0) {
        return Collections.max(notBigEnough, new CompareSizesByArea());
    } else {
        Log.e(TAG, "Couldn't find any suitable preview size");
        return choices[0];
    }
}

来源

此外，您应该查看整个Camera2BasicFragment.java和AutoFitTextureView.java类以获得正确的实现。

Answer 3

我通过不同的方法解决了这个问题。 我得到屏幕的宽度和高度，并计算预览需要多宽或多高才能填满整个屏幕并保持纵横比。 它对我来说效果很好，没有任何扭曲。

添加类成员变量：

public DisplayMetrics mMetrics = new DisplayMetrics();

使用以下作为onMeasure ：

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    int width = MeasureSpec.getSize(widthMeasureSpec);
    int height = MeasureSpec.getSize(heightMeasureSpec);
    if (0 == mRatioWidth || 0 == mRatioHeight) {
        setMeasuredDimension(width, height);
    } else {
        WindowManager windowManager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
        windowManager.getDefaultDisplay().getMetrics(mMetrics);
        double ratio = (double)mRatioWidth / (double)mRatioHeight;
        double invertedRatio = (double)mRatioHeight / (double)mRatioWidth;
        double portraitHeight = width * invertedRatio;
        double portraitWidth = width * (mMetrics.heightPixels / portraitHeight);
        double landscapeWidth = height * ratio;
        double landscapeHeight = (mMetrics.widthPixels / landscapeWidth) * height;

        if (width < height * mRatioWidth / mRatioHeight) {
            setMeasuredDimension((int)portraitWidth, mMetrics.heightPixels);
        } else {
            setMeasuredDimension(mMetrics.widthPixels, (int)landscapeHeight);
        }
    }
}

非常感谢任何反馈;)

最佳男

Answer 4

更改AutoFitTextureView.java文件并设置如下值：

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    int width = MeasureSpec.getSize(widthMeasureSpec);
    int height = MeasureSpec.getSize(heightMeasureSpec);

    if (0 == mRatioWidth || 0 == mRatioHeight) {
        setMeasuredDimension(width, height);
    } else {
        if (width < height * mRatioWidth / mRatioHeight) {
            setMeasuredDimension(width, height);
            Log.d("rlijeolid1",String.valueOf(width)+"\t"+String.valueOf(height));
        } else {
            setMeasuredDimension(width , height);
            Log.d("rlijeolid2",String.valueOf(height * mRatioWidth / mRatioHeight)+"\t"+String.valueOf(height));
        }
    }
}