Android开发（二）：设置Opencv调用的摄像头竖屏显示

参考博客：

OpenCV on Android 开发 （4）竖屏预览图像问题解决方法-续

Opencv读取Android手机摄像头图像使用CameraBridgeViewBase类，而不使用JavaCameraView类，因为Android5.0版本之后JavaCameraView已经被弃用了。CameraBridgeViewBase配置摄像头

解决方案：

打开opencv库的CameraBridgeViewBase.java代码

修改 protected void deliverAndDrawFrame(CvCameraViewFrame frame)函数为：

    /**
     * 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) {
            modified = mListener.onCameraFrame(frame);
        } else {
            modified = frame.rgba();
        }

        boolean bmpValid = true;
        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;
            }
        }

        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);
                /*//旧方法
                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);
                }
                */

                //新方法
                Matrix matrix = new Matrix(); // I rotate it with minimal process
                //matrix.preTranslate((canvas.getWidth() - mCacheBitmap.getWidth()) / 2,(canvas.getHeight() - mCacheBitmap.getHeight()) / 2);
                //matrix.postRotate(90f,(canvas.getWidth()) / 2,(canvas.getHeight()) / 2);
                //float scale = (float) canvas.getWidth() / (float) mCacheBitmap.getHeight();
                //matrix.postScale(scale, scale, canvas.getWidth()/2 , canvas.getHeight()/2 );
                //canvas.drawBitmap(mCacheBitmap, matrix, new Paint());

                if (getDisplay().getRotation() == Surface.ROTATION_0) {
                    matrix.preTranslate((canvas.getWidth() - mCacheBitmap.getWidth()) / 2,(canvas.getHeight() - mCacheBitmap.getHeight()) / 2);
                    matrix.postRotate(90f,(canvas.getWidth()) / 2,(canvas.getHeight()) / 2);
                    float scale = (float) canvas.getWidth() / (float) mCacheBitmap.getHeight();
                    matrix.postScale(scale, scale, canvas.getWidth()/2 , canvas.getHeight()/2 );
                    canvas.drawBitmap(mCacheBitmap, matrix, new Paint());
                } else if (getDisplay().getRotation() == Surface.ROTATION_90) {
                    float scale = (float) canvas.getWidth() / (float) mCacheBitmap.getHeight();
                    matrix.postScale(scale, scale, canvas.getWidth()/2 , canvas.getHeight()/2 );
                    canvas.drawBitmap(mCacheBitmap, matrix, new Paint());
                } else if (getDisplay().getRotation() == Surface.ROTATION_180) {
                    matrix.preTranslate((canvas.getWidth() - mCacheBitmap.getWidth()) / 2,(canvas.getHeight() - mCacheBitmap.getHeight()) / 2);
                    matrix.postRotate(270f,(canvas.getWidth()) / 2,(canvas.getHeight()) / 2);
                    float scale = (float) canvas.getWidth() / (float) mCacheBitmap.getHeight();
                    matrix.postScale(scale, scale, canvas.getWidth()/2 , canvas.getHeight()/2 );
                    canvas.drawBitmap(mCacheBitmap, matrix, new Paint());
                } else if (getDisplay().getRotation() == Surface.ROTATION_270) {
                    matrix.postRotate(180f,(canvas.getWidth()) / 2,(canvas.getHeight()) / 2);
                    float scale = (float) canvas.getWidth() / (float) mCacheBitmap.getHeight();
                    matrix.postScale(scale, scale, canvas.getWidth()/2 , canvas.getHeight()/2 );
                    canvas.drawBitmap(mCacheBitmap, matrix, new Paint());
                }


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

结果：

 竖屏显示方法2：

https://github.com/WuKaik/QuickCamera2