也许这对任何人都有帮助。使用 opencv343 在 android 9 上测试。现在这个全屏和检测人脸在纵向和横向模式下。 CameraBridgeViewBase 类的小改动：
private final Matrix matrix = new Matrix();
……
更改deliverAndDrawFrame() 方法：
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) {
int currentOrientation = getResources().getConfiguration().orientation;
if (currentOrientation == Configuration.ORIENTATION_LANDSCAPE) {
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);
}
} else {
Canvas canvas = getHolder().lockCanvas();
if (canvas != null) {
int saveCount = canvas.save();
canvas.setMatrix(matrix);
mScale = Math.max((float) canvas.getHeight() / mCacheBitmap.getWidth(), (float) canvas.getWidth() / mCacheBitmap.getHeight());
canvas.drawColor(0, android.graphics.PorterDuff.Mode.CLEAR);
if (mScale != 0) {
canvas.drawBitmap(mCacheBitmap, new Rect(0,0,mCacheBitmap.getWidth(), mCacheBitmap.getHeight()),
new Rect((int)((canvas.getWidth() - mCacheBitmap.getWidth()) - mCacheBitmap.getWidth())/2,
(int)(canvas.getHeight() - mScale*mCacheBitmap.getHeight() - mScale*mCacheBitmap.getHeight()/2),
(int)((canvas.getWidth() - mScale*mCacheBitmap.getWidth()) / 2 + mScale*mCacheBitmap.getWidth()),
(int)((canvas.getHeight() - 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);
}
canvas.restoreToCount(saveCount);
if (mFpsMeter != null) {
mFpsMeter.measure();
mFpsMeter.draw(canvas, 20, 30);
}
getHolder().unlockCanvasAndPost(canvas);
}
}
}
}
在 MainActivity 中：
public Mat rotateMat(Mat matImage) {
Mat rotated = matImage.t();
Core.flip(rotated, rotated, 1);
return rotated;
}
@Override
public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
MatOfRect faces = new MatOfRect();
int currentOrientation = getResources().getConfiguration().orientation;
if (currentOrientation == Configuration.ORIENTATION_LANDSCAPE) {
mRgba = inputFrame.rgba();
mGray = inputFrame.gray();
int height = mGray.rows();
if (Math.round(height * 0.2) > 0) {
mFaceSize = (int) Math.round(height * 0.2);
}
cascadeClassifier.detectMultiScale(mGray, faces, 1.1, 3, 2,
new Size(mFaceSize, mFaceSize));
Rect[] facesArray = faces.toArray();
for (int i = 0; i < facesArray.length; i++) {
rectangle(mRgba, facesArray[i].tl(), facesArray[i].br(), FACE_RECT_COLOR, 3);
}
} else {
mRgba = inputFrame.rgba();
mGray = rotateMat(inputFrame.gray());
if (mFaceSize == 0) {
int height = mGray.cols();
if (Math.round(height * 0.2) > 0) {
mFaceSize = (int) Math.round(height * 0.2);
}
}
Mat newMat = rotateMat(mRgba);
if(!isBackCameraOn){
flip(newMat, newMat, -1);
flip(mGray, mGray, -1);
}
if (cascadeClassifier != null)
cascadeClassifier.detectMultiScale(mGray, faces, 1.1, 3, 2, new Size(mFaceSize, mFaceSize));
mGray.release();
Rect[] facesArray = faces.toArray();
for (int i = 0; i < facesArray.length; i++) {
rectangle(newMat, facesArray[i].tl(), facesArray[i].br(), FACE_RECT_COLOR, 3);
}
Imgproc.resize(newMat, mRgba, new Size(mRgba.width(), mRgba.height()));
newMat.release();
}
if(!isBackCameraOn){
flip(mRgba, mRgba, 1);
flip(mGray, mGray, 1);
}
return mRgba;
}