前言

對(duì)于OpenCV的豎屏檢測(cè)盯拱，網(wǎng)絡(luò)有很多盒发，多到百度排名前幾頁(yè)，都是一大堆狡逢，但為什么要寫(xiě)這個(gè)文章迹辐，因?yàn)樗麄兊奈恼拢蟛糠侄际怯袉?wèn)題甚侣，或者是不可用的明吩，以下為他們的實(shí)現(xiàn)方法：
（1）隨便改改canvas繪制方向，并無(wú)其他操作
（2）使用WindowManager檢測(cè)屏幕旋轉(zhuǎn)方向殷费，修改canvas繪制方式
對(duì)于以上兩種做法印荔，實(shí)際是欠佳的低葫，改的是canvas，不是數(shù)據(jù)源仍律，識(shí)別過(guò)程還得橫屏才能識(shí)別嘿悬，難道寫(xiě)這些文章的人都沒(méi)發(fā)現(xiàn)？

方法

首先水泉，官方的Demo善涨，跑的是橫屏邏輯。而橫屏和豎屏最大的區(qū)別就是在于角度和長(zhǎng)寬比不一樣草则。核心原理钢拧，在于寬高的轉(zhuǎn)換，方向的改變炕横。

怎樣改源内？
首先，先對(duì)JavaCameraView代碼進(jìn)行修改份殿，核心改動(dòng)如下：

private class JavaCameraFrame implements CvCameraViewFrame {
        @Override
        public Mat gray() {
            //返回Mat里的選定區(qū)域,這跟Yuv420sp格式緊密相關(guān)
            //return mYuvFrameData.submat(0, mHeight, 0, mWidth);
            //#Modified step3.1
            Core.rotate(mYuvFrameData.submat(0, mHeight, 0, mWidth),
                    portrait_gray,Core.ROTATE_90_CLOCKWISE);
            return portrait_gray;
        }

        @Override
        public Mat rgba() {
            if (mPreviewFormat == ImageFormat.NV21)
                Imgproc.cvtColor(mYuvFrameData, mRgba, Imgproc.COLOR_YUV2RGBA_NV21, 4);
            else if (mPreviewFormat == ImageFormat.YV12)
                Imgproc.cvtColor(mYuvFrameData, mRgba, Imgproc.COLOR_YUV2RGB_I420, 4);  // COLOR_YUV2RGBA_YV12 produces inverted colors
            else
                throw new IllegalArgumentException("Preview Format can be NV21 or YV12");

            //#Modified step3.2
            Core.rotate(mRgba, portrait_rgba,Core.ROTATE_90_CLOCKWISE);

            return portrait_rgba;
        }

        public JavaCameraFrame(Mat Yuv420sp, int width, int height) {
            super();
            mWidth = width;
            mHeight = height;
            //#Modified
            portrait_mHeight=mWidth;
            portrait_mWidth=mHeight;
            portrait_gray=new Mat(portrait_mHeight,portrait_mWidth,CvType.CV_8UC1);
            portrait_rgba=new Mat(portrait_mHeight,portrait_mWidth,CvType.CV_8UC4);
            mYuvFrameData = Yuv420sp;
            mRgba = new Mat();
        }

        public void release() {
            mRgba.release();
        }

        private Mat mYuvFrameData;
        private Mat mRgba;
        private int mWidth;
        private int mHeight;
        //#Modified
        private int portrait_mHeight;
        private int portrait_mWidth;
        private Mat portrait_gray;
        private Mat portrait_rgba;
    }

其實(shí)原理膜钓，就是通過(guò)Core.rotate()方法進(jìn)行旋轉(zhuǎn)。

第二個(gè)卿嘲，修改CameraBridgeViewBase的代碼颂斜，核心代碼如下：

/**
     * This helper method can be called by subclasses to select camera preview size.
     * It goes over the list of the supported preview sizes and selects the maximum one which
     * fits both values set via setMaxFrameSize() and surface frame allocated for this view
     *
     * @param supportedSizes
     * @param surfaceWidth
     * @param surfaceHeight
     * @return optimal frame size
     */
    protected Size calculateCameraFrameSize(List<?> supportedSizes, ListItemAccessor accessor, int surfaceWidth, int surfaceHeight) {
        //選擇一個(gè)相機(jī)frame大小
        int calcWidth = 0;
        int calcHeight = 0;

        //允許的最大width和height
        //#Modified step4
        //相機(jī)Frame的mMaxWidth應(yīng)該與surface的surfaceHeight比
        //相機(jī)Frame的mMaxHeight應(yīng)該與surface的surfaceWidth比
        //int maxAllowedWidth = (mMaxWidth != MAX_UNSPECIFIED && mMaxWidth < surfaceWidth)? mMaxWidth : surfaceWidth;
        //int maxAllowedHeight = (mMaxHeight != MAX_UNSPECIFIED && mMaxHeight < surfaceHeight)? mMaxHeight : surfaceHeight;
        int maxAllowedWidth = (mMaxWidth != MAX_UNSPECIFIED && mMaxWidth < surfaceHeight) ? mMaxWidth : surfaceHeight;
        int maxAllowedHeight = (mMaxHeight != MAX_UNSPECIFIED && mMaxHeight < surfaceWidth) ? mMaxHeight : surfaceWidth;

        for (Object size : supportedSizes) {
            int width = accessor.getWidth(size);
            int height = accessor.getHeight(size);

            //在允許的范圍內(nèi)選擇最大的size
            //client是可通過(guò)設(shè)置小的mMaxWidth,mMaxHeight來(lái)選擇低分辨率frame的
            if (width <= maxAllowedWidth && height <= maxAllowedHeight) {
                if (width >= calcWidth && height >= calcHeight) {
                    calcWidth = (int) width;
                    calcHeight = (int) height;
                }
            }
        }

        return new Size(calcWidth, calcHeight);
    }

/**
     * This method shall be called by the subclasses when they have valid
     * object and want it to be delivered to external client (via callback) and
     * then displayed on the screen.
     *
     * @param frame - the current frame to be delivered
     */
    protected void deliverAndDrawFrame(CvCameraViewFrame frame) {
        Mat modified;

        if (mListener != null) {
            //CvCameraViewListener2 mListener是client指定的
            //這里調(diào)用客戶重載的接口方法且接收返回值
            //這里都是在數(shù)據(jù)處理線程里執(zhí)行的
            modified = mListener.onCameraFrame(frame);
        } else {
            //若client沒(méi)指定CvCameraViewListener2 mListener即client不準(zhǔn)備處理preview數(shù)據(jù)
            //則modified設(shè)置為
            //onPreviewFrame傳回的數(shù)據(jù)轉(zhuǎn)換成的rgba Mat
            modified = frame.rgba();
        }

        //Log Mat的大小和Bitmap的大小
        Log.d("FunnyAR", "mScale: " + mScale + " modified.rows: " + modified.rows()
                + " modified.cols: " + modified.cols() + " mCacheBitmap.getWidth(): " +
                mCacheBitmap.getWidth() + " mCacheBitmap.getHeight() " +
                mCacheBitmap.getHeight());

        //標(biāo)志modified轉(zhuǎn)Bitmap是否成功
        boolean bmpValid = true;
        //若確實(shí)有modified則將其轉(zhuǎn)為Bitmap
        if (modified != null) {
            try {
                Utils.matToBitmap(modified, mCacheBitmap);
            } catch (Exception e) {
                Log.e(TAG, "Mat type: " + modified);
                Log.e(TAG, "Bitmap type: " + mCacheBitmap.getWidth() + "*" + mCacheBitmap.getHeight());
                Log.e(TAG, "Utils.matToBitmap() throws an exception: " + e.getMessage());
                bmpValid = false;
            }
        }
        //轉(zhuǎn)換成功通過(guò)畫(huà)布畫(huà)到surface里
        if (bmpValid && mCacheBitmap != null) {
            Canvas canvas = getHolder().lockCanvas();
            if (canvas != null) {
                canvas.drawColor(0, android.graphics.PorterDuff.Mode.CLEAR);
                if (BuildConfig.DEBUG)
                    Log.d(TAG, "mStretch value: " + mScale);

                if (mScale != 0) {
                    canvas.drawBitmap(mCacheBitmap, new Rect(0, 0, mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
                            new Rect((int) ((canvas.getWidth() - mScale * mCacheBitmap.getWidth()) / 2),
                                    (int) ((canvas.getHeight() - mScale * mCacheBitmap.getHeight()) / 2),
                                    (int) ((canvas.getWidth() - mScale * mCacheBitmap.getWidth()) / 2 + mScale * mCacheBitmap.getWidth()),
                                    (int) ((canvas.getHeight() - mScale * mCacheBitmap.getHeight()) / 2 + mScale * mCacheBitmap.getHeight())), null);
                } else {
                    canvas.drawBitmap(mCacheBitmap, new Rect(0, 0, mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
                            new Rect((canvas.getWidth() - mCacheBitmap.getWidth()) / 2,
                                    (canvas.getHeight() - mCacheBitmap.getHeight()) / 2,
                                    (canvas.getWidth() - mCacheBitmap.getWidth()) / 2 + mCacheBitmap.getWidth(),
                                    (canvas.getHeight() - mCacheBitmap.getHeight()) / 2 + mCacheBitmap.getHeight()), null);
                }

                if (mFpsMeter != null) {
                    mFpsMeter.measure();
                    mFpsMeter.draw(canvas, 20, 30);
                }
                getHolder().unlockCanvasAndPost(canvas);
            }
        }
    }

通過(guò)修改獲取幀大小和幀分發(fā)的函數(shù)，即可拾枣。具體原理就是寬高互換沃疮。

而對(duì)于前置攝像頭的方向，這里不再啰嗦了放前，原理一樣忿磅。

修改文件源碼：鏈接：https://pan.baidu.com/s/1OJs8IgV0TD6_Hq6nU1g9Xg
提取碼：tr4i
復(fù)制這段內(nèi)容后打開(kāi)百度網(wǎng)盤(pán)手機(jī)App，操作更方便哦

that's all-------------------------------------------------------------------------------------------