Android: Shape detection with JavaCV - android

I am new to JavaCV. I am trying to detect largest rectangle in image and outline it with color over original image. I am posting code below which I have tried but it is not working. I am getting edgeDetectedImage properly. I am getting 4 corner points properly. Just cvDrawLine is not working. Please Help if I am missing anything:
OnClick of button I am processing image and showing it again on ImageView.
In onClickListener of button:
if ((new File(path + "trial.jpg")).exists()) {
opencv_core.IplImage originalImage = opencv_imgcodecs.cvLoadImage(path + "trial.jpg", opencv_imgcodecs.CV_IMWRITE_JPEG_QUALITY);
opencv_core.IplImage iplImage = opencv_imgcodecs.cvLoadImage(path + "trial.jpg", opencv_imgcodecs.CV_LOAD_IMAGE_GRAYSCALE);
opencv_core.IplImage edgeDetectedImage = applyCannyRectangleEdgeDetection(iplImage, 80);
opencv_core.CvSeq largestContour = findLargestContour(edgeDetectedImage);
opencv_core.CvPoint[] cvPoints = new opencv_core.CvPoint[4];
for(int i=0; i<largestContour.total();i++)
{
opencv_core.CvPoint cvPoint = new opencv_core.CvPoint(cvGetSeqElem(largestContour, i));
cvPoints[i] = cvPoint;
}
cvDrawLine(originalImage, cvPoints[0], cvPoints[1], opencv_core.CvScalar.YELLOW, 10, 10, 10);
cvDrawLine(originalImage, cvPoints[1], cvPoints[2], opencv_core.CvScalar.YELLOW, 10, 10, 10);
cvDrawLine(originalImage, cvPoints[2], cvPoints[3], opencv_core.CvScalar.YELLOW, 10,10, 10);
cvDrawLine(originalImage, cvPoints[3], cvPoints[0], opencv_core.CvScalar.YELLOW, 10, 10,10);
opencv_imgcodecs.cvSaveImage(path + "img1.jpg", originalImage);
if ((new File(path + "img1.jpg").exists())) {
imageView.setImageDrawable(Drawable.createFromPath(path + "img1.jpg"));
}
}
Method applyCannyRectangleEdgeDetection(IplImage, int):
private opencv_core.IplImage applyCannyRectangleEdgeDetection(opencv_core.IplImage iplImage, int percent) {
opencv_core.IplImage destImage = downScaleImage(iplImage, percent);
OpenCVFrameConverter.ToMat converterToMat = new OpenCVFrameConverter.ToMat();
Frame grayImageFrame = converterToMat.convert(destImage);
opencv_core.Mat grayImageMat = converterToMat.convertToMat(grayImageFrame);
GaussianBlur(grayImageMat, grayImageMat, new opencv_core.Size(5, 5), 0.0, 0.0, BORDER_DEFAULT);
destImage = converterToMat.convertToIplImage(grayImageFrame);
cvErode(destImage, destImage);
cvDilate(destImage, destImage);
cvCanny(destImage, destImage, 20, 55);
return destImage;
}
Method downScaleImage(IplImage, int)
private opencv_core.IplImage downScaleImage(opencv_core.IplImage srcImage, int percent) {
opencv_core.IplImage destImage = cvCreateImage(cvSize((srcImage.width() * percent) / 100, (srcImage.height() * percent) / 100), srcImage.depth(), srcImage.nChannels());
cvResize(srcImage, destImage);
return destImage;
}
Method findLargestContour(IplImage)
private opencv_core.CvSeq findLargestContour(opencv_core.IplImage edgeDetectedImage) {
opencv_core.IplImage foundContoursOfImage = cvCloneImage(edgeDetectedImage);
opencv_core.CvMemStorage memory = new opencv_core.CvMemStorage().create();
opencv_core.CvSeq contours = new opencv_core.CvSeq();
cvFindContours(foundContoursOfImage, memory, contours, Loader.sizeof(opencv_core.CvContour.class), CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, new opencv_core.CvPoint(0, 0));
int maxWidth = 0;
int maxHeight = 0;
opencv_core.CvRect contr = null;
opencv_core.CvSeq seqFound = null;
opencv_core.CvSeq nextSeq;
for (nextSeq = contours; nextSeq != null; nextSeq = nextSeq.h_next()) {
contr = cvBoundingRect(nextSeq, 0);
if ((contr.width() >= maxWidth) && (contr.height() >= maxHeight)) {
maxHeight = contr.height();
maxWidth = contr.width();
seqFound = nextSeq;
}
}
opencv_core.CvSeq result = cvApproxPoly(seqFound, Loader.sizeof(opencv_core.CvContour.class), memory, CV_POLY_APPROX_DP, cvContourPerimeter(seqFound) * 0.1, 0);
return result;
}

Sorry this should be in comments but I don't have enough reputation. What I can see from your code is that the canny is applied on a downscaled image and so is the contour. You are drawing the lines on the original image (which isn't downscaled by percent) so naturally it wouldn't look correct (if it isn't looking correct but something is being drawn). Otherwise, you should mention the color space of the image, it doesn't matter for drawing but does for canny.

Related

Running OpenCV eye detection from within Android service

I want to run eye detection by OpenCV4Android from Android background service. I have a piece of code that runs well but as an Activity not service. I understand that the Android camera must have a preview to open. So I have created a preview (small one to make it looks hidden, since I want the processing to be in the background) and started the camera for recording. The camera starts successfully, but OpenCV doesn't detect eyes and faces. It only loads the xml classifiers. I expected the callbacks of OpenCV like onCameraViewStarted and onCameraFrame to get called when I open the camera for recording, but they didn't.
Here is the code:
public class BackgroundService extends Service implements SurfaceHolder.Callback, CameraBridgeViewBase.CvCameraViewListener2 {
private static final String TAG = "OCVSample::Activity";
private static final Scalar FACE_RECT_COLOR = new Scalar(0, 255, 0, 255);
public static final int JAVA_DETECTOR = 0;
private static final int TM_SQDIFF = 0;
private static final int TM_SQDIFF_NORMED = 1;
private static final int TM_CCOEFF = 2;
private static final int TM_CCOEFF_NORMED = 3;
private static final int TM_CCORR = 4;
private static final int TM_CCORR_NORMED = 5;
private int learn_frames = 0;
private Mat templateR;//right eye template
private Mat templateL; // left eye template
int method = 0;
private MenuItem mItemFace50;
private MenuItem mItemFace40;
private MenuItem mItemFace30;
private MenuItem mItemFace20;
private MenuItem mItemType;
private Mat mRgba;
private Mat mGray;
// matrix for zooming
private Mat mZoomWindow;
private Mat mZoomWindow2;
private File mCascadeFile;
private CascadeClassifier mJavaDetector;
private CascadeClassifier mJavaDetectorEye;
private int mDetectorType = JAVA_DETECTOR;
private String[] mDetectorName;
private float mRelativeFaceSize = 0.2f;
private int mAbsoluteFaceSize = 0;
private CameraBridgeViewBase mOpenCvCameraView;
private SeekBar mMethodSeekbar;
private TextView mValue;
double xCenter = -1;
double yCenter = -1;
MediaRecorder mediaRecorder;
// Binder given to clients
private final IBinder mBinder = new LocalBinder();
public class LocalBinder extends Binder {
BackgroundService getService() {
// Return this instance of this service so clients can call public methods
return BackgroundService.this;
}
}//end inner class that returns an instance of the service.
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}//end onBind.
private WindowManager windowManager;
private SurfaceView surfaceView;
private Camera camera = null;
#Override
public void onCreate() {
// Start foreground service to avoid unexpected kill
Notification notification = new Notification.Builder(this)
.setContentTitle("Background Video Recorder")
.setContentText("")
.setSmallIcon(R.drawable.vecsat_logo)
.build();
startForeground(1234, notification);
// Create new SurfaceView, set its size to 1x1, move it to the top left corner and set this service as a callback
windowManager = (WindowManager) this.getSystemService(Context.WINDOW_SERVICE);
surfaceView = new SurfaceView(this);
WindowManager.LayoutParams layoutParams = new WindowManager.LayoutParams(
100, 100,
WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,
WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH,
PixelFormat.TRANSLUCENT
);
Log.i(TAG, "100 x 100 executed");
layoutParams.gravity = Gravity.LEFT | Gravity.TOP;
windowManager.addView(surfaceView, layoutParams);
surfaceView.getHolder().addCallback(this);
//constructor:
mDetectorName = new String[2];// contains 3 positions..
mDetectorName[JAVA_DETECTOR] = "Java"; //let the detector be of type java detector, specify that in the JAVA_DETECTOR index.
Log.i(TAG, "Instantiated new " + ((Object) this).getClass().getSimpleName());
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_11, this,
mLoaderCallback); //once the application is resumed reload the library.
}
// Method called right after Surface created (initializing and starting MediaRecorder)
#Override
public void surfaceCreated(SurfaceHolder surfaceHolder) {
Log.i(TAG, "surfaceCreated method");
camera = Camera.open(1);
camera.unlock();
mediaRecorder = new MediaRecorder();
mediaRecorder.setPreviewDisplay(surfaceHolder.getSurface());
mediaRecorder.setCamera(camera);
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
mediaRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH));
mediaRecorder.setOutputFile(
Environment.getExternalStorageDirectory()+"/"+
DateFormat.format("yyyy-MM-dd_kk-mm-ss", new Date().getTime())+
".mp4"
);
try { mediaRecorder.prepare(); } catch (Exception e) {}
mediaRecorder.start();
}
// Stop recording and remove SurfaceView
#Override
public void onDestroy() {
Log.i(TAG, "surfaceDestroyed method");
camera.lock();
camera.release();
windowManager.removeView(surfaceView);
}
#Override
public void surfaceChanged(SurfaceHolder surfaceHolder, int format, int width, int height) {}
#Override
public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
}
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
#Override
public void onManagerConnected(int status) {
//int status, status of initialization, sucess or not..
//now make a switch for the status cases: under success case do the work, load the classifiers..
switch (status) {
case LoaderCallbackInterface.SUCCESS: {
Log.i(TAG, "OpenCV loaded successfully"); // was loaded and initialized successfully..
try {
// load cascade file from application resources
InputStream is = getResources().openRawResource(
R.raw.lbpcascade_frontalface); // get the face classifier from the resource.
File cascadeDir = getDir("cascade", Context.MODE_PRIVATE);
mCascadeFile = new File(cascadeDir,
"lbpcascade_frontalface.xml"); // create a directory inside your app, and a file inside it to store the
FileOutputStream os = new FileOutputStream(mCascadeFile); // prepare an output stream that will write the classifier's code on the file in the app.
//read and write
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = is.read(buffer)) != -1) {
os.write(buffer, 0, bytesRead);
}
is.close();
os.close();
// --------------------------------- load left eye
// classificator -----------------------------------
InputStream iser = getResources().openRawResource(
R.raw.haarcascade_lefteye_2splits);
File cascadeDirER = getDir("cascadeER",
Context.MODE_PRIVATE);
File cascadeFileER = new File(cascadeDirER,
"haarcascade_eye_right.xml");
FileOutputStream oser = new FileOutputStream(cascadeFileER);
byte[] bufferER = new byte[4096];
int bytesReadER;
while ((bytesReadER = iser.read(bufferER)) != -1) {
oser.write(bufferER, 0, bytesReadER);
}
iser.close();
oser.close();
//check if you can load the classifer.
mJavaDetector = new CascadeClassifier(
mCascadeFile.getAbsolutePath());
if (mJavaDetector.empty()) {
Toast.makeText(getApplicationContext(), "face classifier error", Toast.LENGTH_LONG).show();
Log.e(TAG, "Failed to load cascade face classifier");
mJavaDetector = null;
} else
Log.i(TAG, "Loaded cascade classifier from "
+ mCascadeFile.getAbsolutePath());
mJavaDetectorEye = new CascadeClassifier(
cascadeFileER.getAbsolutePath());
if (mJavaDetectorEye.empty()) {
Toast.makeText(getApplicationContext(), "eye classifer error", Toast.LENGTH_LONG).show();
Log.e(TAG, "Failed to load cascade eye classifier");
mJavaDetectorEye = null;
} else
Log.i(TAG, "Loaded cascade classifier from "
+ mCascadeFile.getAbsolutePath());
cascadeDir.delete();
} catch (IOException e) {
e.printStackTrace();
Log.e(TAG, "Failed to load cascade. Exception thrown: " + e);
}
//Whether classifiers are opened or not, open the front camera.
// mOpenCvCameraView.setCameraIndex(1);
//mOpenCvCameraView.enableFpsMeter(); // What is this? This method enables label with fps value on the screen
// mOpenCvCameraView.enableView(); // What? This means enable connecting to the camera.
}
break;
default: {
//When the loading of the libarary is failed
super.onManagerConnected(status);
}
break;
}
}
}; // end the class.
public void onCameraViewStarted(int width, int height) {
Log.i(TAG, "onCameraViewStarted method");
//onCameraViewStarted callback will be delivered only after enableView is called and surface is available
//This method is a member of CvCameraViewListener2, and we must implement it.
mGray = new Mat(); //initialize new gray scale matrix to contain the img pixels.
mRgba = new Mat(); //initialize new rgb matrix to contain the img pixels.
}
public void onCameraViewStopped() {
Log.i(TAG, "onCameraViewStopped method");
//Release the allocated memory
//release the matrix, this releases the allocated space in memory, since mat contains a header that contains img info and a pointer that points to the matrix in the memory.
mGray.release();
mRgba.release();
mZoomWindow.release();
mZoomWindow2.release();
}
public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
Log.i(TAG, "onCameraFrame method");
//This method is a member of CvCameraViewListener2, and we must implement it.
// In this method we get every frame from the camera and process it in order to track the objects.
//inputFrame is the received frame from the camera.
mRgba = inputFrame.rgba(); //convert the frame to rgba scale, then assign this value to the rgba Mat img matrix.
mGray = inputFrame.gray(); //convert the frame to gray scale, then assign this value to the gray Mat img matrix.
//Shall we consider Flipping the camera img horizontally.
if (mAbsoluteFaceSize == 0) {
int height = mGray.rows(); //get the height of the captured frame stored in mgray Mat array (rows), why gray to rgb???
if (Math.round(height * mRelativeFaceSize) > 0) { //multiply that height with 0.2... Is the result > 0?
//if yes this indicates that there is a frame that was captured (it's height is not zero), so set the face size to
// Math.round(height * mRelativeFaceSize)
mAbsoluteFaceSize = Math.round(height * mRelativeFaceSize);
}
}
if (mZoomWindow == null || mZoomWindow2 == null)
CreateAuxiliaryMats();
MatOfRect faces = new MatOfRect(); //a matrix that will contain rectangles around the face (including the faces inside the rectangles), it will be filled by detectMultiScale method.
//if mJavaDetector is not null, this contains the face classifier that we have loaded previously
if (mJavaDetector != null)
//if not null, use this classifier to detect faces.
mJavaDetector.detectMultiScale(mGray, faces, 1.1, 2,
2, // TODO: objdetect.CV_HAAR_SCALE_IMAGE
new Size(mAbsoluteFaceSize, mAbsoluteFaceSize),
new Size());
//in th function detectMultiScale above,
// faces is the array that will contain the rectangles around the detected face.
// the 3rd param: specifies how much the image size is reduced at each image scale.
//4th param: Parameter specifying how many neighbors each candidate rectangle should have to retain it.
//5: :)
//6: Minimum possible object size. Objects smaller than that are ignored (if you set a very small minimum value, your app will run heavily).
//7: Maximum possible object size. Objects larger than that are ignored. Both minimum and maximum should be set carefully to avoid slow running of the app.
Rect[] facesArray = faces.toArray(); //array of faces
for (int i = 0; i < facesArray.length; i++) {
/* Imgproc.rectangle(mRgba, facesArray[i].tl(), facesArray[i].br(),
FACE_RECT_COLOR, 3);*/
//Now draw rectangles around the obtained faces, and a circle at each rectangle center.
//mrgba in the line bellow means that the rectangle should be drawn on the colored img.
//facesArray[i].tl() returns a Point: Template class for 2D points specified by its coordinates x and y -> Template class
// facesArray[i].x and facesArray[i].y are the x and y coords of the top left top corner.
Core.rectangle(mRgba, facesArray[i].tl(), facesArray[i].br(), FACE_RECT_COLOR, 3);
//calculate the center in x and y coords.
xCenter = (facesArray[i].x + facesArray[i].width + facesArray[i].x) / 2;
yCenter = (facesArray[i].y + facesArray[i].y + facesArray[i].height) / 2;
Point center = new Point(xCenter, yCenter); //store the center.
//Imgproc.circle(mRgba, center, 10, new Scalar(255, 0, 0, 255), 3);
Core.circle(mRgba, center, 10, new Scalar(255, 0, 0, 255), 3); //draw a red circle at the center of the face rectangle.
/*Imgproc.putText(mRgba, "[" + center.x + "," + center.y + "]",
new Point(center.x + 20, center.y + 20),
Core.FONT_HERSHEY_SIMPLEX, 0.7, new Scalar(255, 255, 255,
255));*/
//write the coordinates of the rectangle center:
Core.putText(mRgba, "[" + center.x + "," + center.y + "]",
new Point(center.x + 20, center.y + 20) , // this is the bottom left corner of the text string
Core.FONT_HERSHEY_SIMPLEX, 0.7, new Scalar(255, 255, 255,
255));
Rect r = facesArray[i]; //get the currect face, we want to use it to detect the eyes inside it.
// compute the eye area
//Rect (x, y, w, h)
Rect eyearea = new Rect(r.x + r.width / 8,
(int) (r.y + (r.height / 4.5)), r.width - 2 * r.width / 8,
(int) (r.height / 3.0));
// split it
Rect eyearea_right = new Rect(r.x + r.width / 16,
(int) (r.y + (r.height / 4.5)),
(r.width - 2 * r.width / 16) / 2, (int) (r.height / 3.0));
Rect eyearea_left = new Rect(r.x + r.width / 16
+ (r.width - 2 * r.width / 16) / 2,
(int) (r.y + (r.height / 4.5)),
(r.width - 2 * r.width / 16) / 2, (int) (r.height / 3.0));
// draw the area - mGray is working grayscale mat, if you want to
// see area in rgb preview, change mGray to mRgba
/*Imgproc.rectangle(mRgba, eyearea_left.tl(), eyearea_left.br(),
new Scalar(255, 0, 0, 255), 2);
Imgproc.rectangle(mRgba, eyearea_right.tl(), eyearea_right.br(),
new Scalar(255, 0, 0, 255), 2);*/
Core.rectangle(mRgba, eyearea_left.tl(), eyearea_left.br(),
new Scalar(255, 0, 0, 255), 2);
Core.rectangle(mRgba, eyearea_right.tl(), eyearea_right.br(),
new Scalar(255, 0, 0, 255), 2);
if (learn_frames < 5) {
// no learned frames -> Learn templates from at least 5 frames..
templateR = get_template(mJavaDetectorEye, eyearea_right, 24);
templateL = get_template(mJavaDetectorEye, eyearea_left, 24);
learn_frames++;
} else {
// Learning finished, use the new templates for template
// matching
match_eye(eyearea_right, templateR, method);
match_eye(eyearea_left, templateL, method);
}
// cut eye areas and put them to zoom windows
Imgproc.resize(mRgba.submat(eyearea_left), mZoomWindow2,
mZoomWindow2.size());
Imgproc.resize(mRgba.submat(eyearea_right), mZoomWindow,
mZoomWindow.size());
}
return mRgba;
}
private void setMinFaceSize(float faceSize) {
mRelativeFaceSize = faceSize;
mAbsoluteFaceSize = 0;
}
private void CreateAuxiliaryMats() {
if (mGray.empty())
return;
int rows = mGray.rows();
int cols = mGray.cols();
if (mZoomWindow == null) {
mZoomWindow = mRgba.submat(rows / 2 + rows / 10, rows, cols / 2
+ cols / 10, cols);
mZoomWindow2 = mRgba.submat(0, rows / 2 - rows / 10, cols / 2
+ cols / 10, cols);
}
}
private void match_eye(Rect area, Mat mTemplate, int type) {
Point matchLoc;
Mat mROI = mGray.submat(area);
int result_cols = mROI.cols() - mTemplate.cols() + 1;
int result_rows = mROI.rows() - mTemplate.rows() + 1;
// Check for bad template size
if (mTemplate.cols() == 0 || mTemplate.rows() == 0) {
return ;
}
Mat mResult = new Mat(result_cols, result_rows, CvType.CV_8U);
switch (type) {
case TM_SQDIFF:
Imgproc.matchTemplate(mROI, mTemplate, mResult, Imgproc.TM_SQDIFF);
break;
case TM_SQDIFF_NORMED:
Imgproc.matchTemplate(mROI, mTemplate, mResult,
Imgproc.TM_SQDIFF_NORMED);
break;
case TM_CCOEFF:
Imgproc.matchTemplate(mROI, mTemplate, mResult, Imgproc.TM_CCOEFF);
break;
case TM_CCOEFF_NORMED:
Imgproc.matchTemplate(mROI, mTemplate, mResult,
Imgproc.TM_CCOEFF_NORMED);
break;
case TM_CCORR:
Imgproc.matchTemplate(mROI, mTemplate, mResult, Imgproc.TM_CCORR);
break;
case TM_CCORR_NORMED:
Imgproc.matchTemplate(mROI, mTemplate, mResult,
Imgproc.TM_CCORR_NORMED);
break;
}
Core.MinMaxLocResult mmres = Core.minMaxLoc(mResult);
// there is difference in matching methods - best match is max/min value
if (type == TM_SQDIFF || type == TM_SQDIFF_NORMED) {
matchLoc = mmres.minLoc;
} else {
matchLoc = mmres.maxLoc;
}
Point matchLoc_tx = new Point(matchLoc.x + area.x, matchLoc.y + area.y);
Point matchLoc_ty = new Point(matchLoc.x + mTemplate.cols() + area.x,
matchLoc.y + mTemplate.rows() + area.y);
/*Imgproc.rectangle(mRgba, matchLoc_tx, matchLoc_ty, new Scalar(255, 255, 0,
255));*/
Core.rectangle(mRgba, matchLoc_tx, matchLoc_ty, new Scalar(255, 255, 0,
255));
Rect rec = new Rect(matchLoc_tx,matchLoc_ty);
}
private Mat get_template(CascadeClassifier clasificator, Rect area, int size) {
Mat template = new Mat(); //prepare a Mat which will serve as a template for eyes.
Mat mROI = mGray.submat(area); //detect only region of interest which is represented by the area. So, from the total Mat get only the submat that represent roi.
MatOfRect eyes = new MatOfRect(); //will be around eyes (including eyes), this will be filled by detectMultiScale
Point iris = new Point(); //to identify iris.
Rect eye_template = new Rect();
clasificator.detectMultiScale(mROI, eyes, 1.15, 2,
Objdetect.CASCADE_FIND_BIGGEST_OBJECT
| Objdetect.CASCADE_SCALE_IMAGE, new Size(30, 30),
new Size());
Rect[] eyesArray = eyes.toArray(); //get the detected eyes
for (int i = 0; i < eyesArray.length;) {
Rect e = eyesArray[i];
e.x = area.x + e.x; //the starting x coordinates of the rect (area) around the eye + the area
e.y = area.y + e.y;
Rect eye_only_rectangle = new Rect((int) e.tl().x,
(int) (e.tl().y + e.height * 0.4), (int) e.width,
(int) (e.height * 0.6));
mROI = mGray.submat(eye_only_rectangle);
Mat vyrez = mRgba.submat(eye_only_rectangle);
Core.MinMaxLocResult mmG = Core.minMaxLoc(mROI);
// Imgproc.circle(vyrez, mmG.minLoc, 2, new Scalar(255, 255, 255, 255), 2);
Core.circle(vyrez, mmG.minLoc, 2, new Scalar(255, 255, 255, 255), 2);
iris.x = mmG.minLoc.x + eye_only_rectangle.x;
iris.y = mmG.minLoc.y + eye_only_rectangle.y;
eye_template = new Rect((int) iris.x - size / 2, (int) iris.y
- size / 2, size, size);
/*Imgproc.rectangle(mRgba, eye_template.tl(), eye_template.br(),
new Scalar(255, 0, 0, 255), 2);*/
Core.rectangle(mRgba, eye_template.tl(), eye_template.br(),
new Scalar(255, 0, 0, 255), 2);
template = (mGray.submat(eye_template)).clone();
return template;
}
return template;
}
public void onRecreateClick(View v)
{
learn_frames = 0;
}
}
Notice that the camera opens successfully for recording, and the xml files are loaded, but nothing happens after that. I made the window size as 100 x 100 just for testing purposes, I know it should be 1 x 1.
Can anyone please tell me how to solve this problem? How can I run opencv video camera for face and eye tracking from background service?
I tried to get the opencv camera in a service as you are doing but I was unable to get neither onCameraFrame nor onCameraViewStarted callbacks, which meant that the camera was not getting initialized. After a bunch of tries:
Setting the preview to INVISIBLE/GONE -> not working
Setting the preview size to a pixel size of 1×1 or respecting
camera's aspect ratio 4x3 ->not working
Setting the preview outside the screen -> not working
I found out that opencv camera needs to be previewed with view's size, only that way I was able to get onCameraFrame callback.
Fortunately, I could place another element on top of the camera preview to hide it, and show the alarms only.
You could find a simple CameraInService example here, hope it is useful for you.

Use RenderScript to emboss a shape in android

This question is base on link.
I tried out #miloslaw-smyk answer. However I could not get it to work. I am not sure what createPath(1) means. I am not sure how to create a path with a certain stroke width. We can do that using the fillpaint. Anyway below I have shown the complete code.Problem is I don't see any emboss effect shown by the original link (see output image below). Please let me know what I have done wrong. (I am using targetSdkVersion 23 and device is on updated 4.1.2 android)
private Bitmap puzzelImage; // screen size image
private Bitmap mBitmapIn;
private Bitmap mBitmapPuzzle;
private RenderScript mRS;
private Allocation mInAllocation;
private Allocation mPuzzleAllocation;
private Allocation mCutterAllocation;
private Allocation mOutAllocation;
private Allocation mOutAllocation2;
private Allocation mAllocationHist;
private ScriptIntrinsicBlur mScriptBlur;
private ScriptIntrinsicBlend mScriptBlend;
private ScriptIntrinsicHistogram mScriptHistogram;
private ScriptIntrinsicLUT mScriptLUT;
public Activity ctx;
private int bw = 780;
private int bh = 780; Path path2;
private void init() {
if (puzzel.mybitmap == null)
return;
bw = puzzelImage.getWidth();
bh = puzzelImage.getHeight();
mBitmapIn = puzzelImage ;
mBitmapPuzzle = Bitmap.createBitmap(bw, bh, Bitmap.Config.ARGB_8888); // this will hold the puzzle
Canvas c = new Canvas(mBitmapPuzzle);
createPath();
//path2 = path1;
fillPaint.setStrokeWidth(5);
c.drawPath(path2, fillPaint); // draw it on canvas
createScript(); // get renderscripts and Allocations ready
// Apply gaussian blur of radius 25 to our drawing
mScriptBlur.setRadius(25);
mScriptBlur.setInput(mPuzzleAllocation);
mScriptBlur.forEach(mOutAllocation);
// Now apply the blur of radius 1
mScriptBlur.setRadius(1);
mScriptBlur.setInput(mPuzzleAllocation);
mScriptBlur.forEach(mOutAllocation2);
// Subtract one blur result from another
mScriptBlend.forEachSubtract(mOutAllocation, mOutAllocation2);
// We now want to normalize the result (e.g. make it use full 0-255 range).
// To do that, we will first compute the histogram of our image
mScriptHistogram.setOutput(mAllocationHist);
mScriptHistogram.forEach(mOutAllocation2);
// copy the histogram to Java array...
int []hist = new int[256 * 4];
mAllocationHist.copyTo(hist);
// ...and walk it from the end looking for the first non empty bin
int i;
for(i = 255; i > 1; i--)
if((hist[i * 4] | hist[i * 4 + 1] | hist[i * 4 + 2]) != 0)
break;
// Now setup the LUTs that will map the image to the new, wider range.
// We also use the opportunity to inverse the image ("255 -").
for(int x = 0; x <= i; x++)
{
int val = 255 - x * 255 / i;
mScriptLUT.setAlpha(x, 255); // note we always make it fully opaque
mScriptLUT.setRed(x, val);
mScriptLUT.setGreen(x, val);
mScriptLUT.setBlue(x, val);
}
// the mapping itself.
mScriptLUT.forEach(mOutAllocation2, mOutAllocation);
Bitmap mBitmapCutter = Bitmap.createBitmap(bw, bh, Bitmap.Config.ARGB_8888);
c = new Canvas(mBitmapCutter);
createPath();
fillPaint.setStrokeWidth(1);
c.drawPath(path2, fillPaint);
mCutterAllocation = Allocation.createFromBitmap(mRS, mBitmapCutter);
// cookie cutter now
mScriptBlend.forEachDstIn(mCutterAllocation, mOutAllocation);
mScriptBlend.forEachMultiply(mOutAllocation, mInAllocation);
mInAllocation.copyTo(mBitmapPuzzle);
}
private void createScript() {
try {
mRS = RenderScript.create(ctx);
mPuzzleAllocation = Allocation.createFromBitmap(mRS, mBitmapPuzzle);
// three following allocations could actually use createSized(),
// but the code would be longer.
mInAllocation = Allocation.createFromBitmap(mRS, mBitmapIn);
mOutAllocation = Allocation.createFromBitmap(mRS, mBitmapPuzzle);
mOutAllocation2 = Allocation.createFromBitmap(mRS, mBitmapPuzzle);
mAllocationHist = Allocation.createSized(mRS, Element.I32_3(mRS), 256);
mScriptBlur = ScriptIntrinsicBlur.create(mRS, Element.U8_4(mRS));
mScriptBlend = ScriptIntrinsicBlend.create(mRS, Element.U8_4(mRS));
mScriptHistogram = ScriptIntrinsicHistogram.create(mRS, Element.U8_4(mRS));
mScriptLUT = ScriptIntrinsicLUT.create(mRS, Element.U8_4(mRS));
}catch (Exception e)
{
}
}
public void createPath()
{
path2 = new Path();
//path 1 samll one
Point[] araay = new Point[]{new Point(144,320),new Point(109,200), new Point(171,308),new Point(178,240),new Point(171,172),new Point(109,282),new Point(144,160)};
AddBeziers(path2, araay, 320, 144);
AddLine(path2, 216, 144 );
AddLine(path2, 216, 216 );
AddLine(path2, 144, 320);
fillPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
fillPaint.setColor(Color.WHITE);
fillPaint.setFlags(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG);
fillPaint.setAntiAlias(true);
fillPaint.setDither(true);
fillPaint.setStrokeJoin(Paint.Join.ROUND);
fillPaint.setStrokeCap(Paint.Cap.ROUND);
fillPaint.setStyle(Paint.Style.FILL_AND_STROKE);
}
protected Path AddLine(Path path, int endX, int endY) {
//path.moveTo(startX, startY);
path.lineTo(endX, endY);
return path;
}
protected Path AddBeziers(Path path, Point[] points, int lastX, int lastY) {
if (points[0].X != lastX && points[0].Y != lastY)
path.moveTo(points[0].X, points[0].Y);
int index = 1;
path.cubicTo(points[index].X, points[index].Y, points[index + 1].X,
points[index + 1].Y, points[index + 2].X, points[index + 2].Y);
index = index + 3;
path.cubicTo(points[index].X, points[index].Y, points[index + 1].X,
points[index + 1].Y, points[index + 2].X, points[index + 2].Y);
return path;
/*pointsCounter = points.length;
//point = new PointNew(new PointF(points[1].X, points[1].Y));
prev = new PointNew(new PointF(points[0].X, points[0].Y));
//next = new PointNew(new PointF(points[2].X, points[2].Y));
for (int i =1; i < points.length; i++)
appendToPath(path, new PointF(points[i].X, points[i].Y), null);
return path;*/
}
#Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(mBitmapPuzzle, 0, 0, fillPaint);
super.onDraw(canvas);
}
Can you try with my version of createPath()? I modified it slightly to draw larger puzzle and to accept stroke width as an argument.
public void createPath(int strokeWidth)
{
//path 2 Big one
Point[]araay = new Point[]{new Point(144,320),new Point(109,200), new Point(171,308),new Point(178,240),new Point(171,172),new Point(109,282),new Point(144,160)};
Point[]braay = new Point[araay.length];
int idx = 6;
for(Point p : araay)
braay[idx--] = new Point((200 + p.x), p.y);
path2.moveTo(144,320);
AddBeziers(path2, araay, 320, 144);
AddLine(path2, 216, 144);
AddBeziers(path2, braay, 320, 144);
AddLine(path2, 144, 320);
path2.close();
Matrix m = new Matrix();
m.setScale(2, 2);
path2.transform(m);
MaskFilter mEmboss = new EmbossMaskFilter(new float[] { 1, 1, 1 }, 0.4f, 6, 3.5f);
fillPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
fillPaint.setColor(Color.WHITE);
fillPaint.setFlags(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG);
fillPaint.setAntiAlias(true);
fillPaint.setDither(true);
fillPaint.setStrokeJoin(Paint.Join.ROUND);
fillPaint.setStrokeCap(Paint.Cap.ROUND);
fillPaint.setStrokeWidth(strokeWidth);
fillPaint.setStyle(Paint.Style.FILL_AND_STROKE);
fillPaint.setStrokeMiter(0);
}

Transformation of a bitmap- Android

I'm having a bit of a problem with a (very basic and crude) implementation of Parallax. Basically I have an image which is supposed to move across the screen at a slightly different rate to the background. It does this- until it reaches the end of the image. It seems to loop back to the start of the image-- but when it reaches the end of the image, it seems to stretch the bitmap out across the length of the screen until it's stretched out completely- then it resets itself.
I can't attach a screenshot (not enough rep) but here's the code.
Init method:
private void init(Context context) {
screenSize = new Point();
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
wm.getDefaultDisplay().getSize(screenSize);
backGroundViewPort = new Rect();
cityscapeRect = new Rect();
backGroundViewPort.set(0, 0, 400, 300);
GGRAssetManager ggrAssetManager = new GGRAssetManager(context);
background = ggrAssetManager.loadImage("background.jpg");
cityscape = ggrAssetManager.loadImage("cityscape3.png");
clouds = ggrAssetManager.loadImage("clouds.png");
backGroundViewPort.set(0, 0, 400, 300);
}
DoUpdate method:
public void doUpdate() {
Game.getInstance().viewport.set(Math.max(0, (int) (game.getPlayer().getxPos() - screenSize.x / 2)),
0,
(int) (game.getPlayer().getxPos() + (screenSize.x / 2)),
screenSize.y);
if (backGroundViewPort.right + 1 >= background.getWidth()) {
backGroundViewPort.left = 0;
backGroundViewPort.right = 400;
} else {
backGroundViewPort.right += 1;
backGroundViewPort.left += 1;
}
if (cityscapeRect.right + 1 >= cityscape.getWidth()) {
cityscapeRect.left = cityscape.getWidth() - screenSize.x;
cityscapeRect.right = 0;
} else {
cityscapeRect.right += 1;
cityscapeRect.left += 1;
}
}
DoDraw method:
public void doDraw(Canvas canvas) {
//PARALLAX
backGroundRect.set(0, 0, screenSize.x, screenSize.y);
canvas.drawBitmap(background, backGroundViewPort, backGroundRect, null);
cityscapeRect.set(0, screenSize.y/2, (screenSize.x), screenSize.y);
Paint paint = new Paint();
paint.setAlpha(150);
canvas.drawBitmap(cityscape, backGroundViewPort, cityscapeRect, paint);
}
I'm sure it's to do with the rectangles, but I don't know how to fix it. Help is greatly appreciated.

Find dominant color in a camera frame in OpenCV Android

I want to get the dominant color in an Android CvCameraViewFrame object. I use the following OpenCV Android code to do that. This code is converted from OpenCV c++ code to OpenCV Android code. In the following code I loop through all the pixels in my camera frame and find the color of each pixel and store them in a HashMap to find the dominant color at the end of the loop. To loop through each pixel it takes about 30 seconds. This is unacceptable for me. Could somebody please review this code and point me how can I find the dominant color in a camera frame.
private String[] colors = {"cBLACK", "cWHITE", "cGREY", "cRED", "cORANGE", "cYELLOW", "cGREEN", "cAQUA", "cBLUE", "cPURPLE", "cPINK", "cRED"};
public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
mRgba = inputFrame.rgba();
if (mIsColorSelected) {
Imgproc.cvtColor(mRgba, mRgba, Imgproc.COLOR_BGR2HSV);
int h = mRgba.height(); // Pixel height
int w = mRgba.width(); // Pixel width
int rowSize = (int)mRgba.step1(); // Size of row in bytes, including extra padding
float initialConfidence = 1.0f;
Map<String, Integer> tallyColors = new HashMap<String, Integer>();
byte[] pixelsTotal = new byte[h*rowSize];
mRgba.get(0,0,pixelsTotal);
//This for loop takes about 30 seconds to process for my camera frame
for (int y=0; y<h; y++) {
for (int x=0; x<w; x++) {
// Get the HSV pixel components
int hVal = (int)pixelsTotal[(y*rowSize) + x + 0]; // Hue
int sVal = (int)pixelsTotal[(y*rowSize) + x + 1]; // Saturation
int vVal = (int)pixelsTotal[(y*rowSize) + x + 2]; // Value (Brightness)
// Determine what type of color the HSV pixel is.
String ctype = getPixelColorType(hVal, sVal, vVal);
// Keep count of these colors.
int totalNum = 0;
try{
totalNum = tallyColors.get(ctype);
} catch(Exception ex){
totalNum = 0;
}
totalNum++;
tallyColors.put(ctype, totalNum);
}
}
int tallyMaxIndex = 0;
int tallyMaxCount = -1;
int pixels = w * h;
for (int i=0; i<colors.length; i++) {
String v = colors[i];
int pixCount;
try{
pixCount = tallyColors.get(v);
} catch(Exception e){
pixCount = 0;
}
Log.i(TAG, v + " - " + (pixCount*100/pixels) + "%, ");
if (pixCount > tallyMaxCount) {
tallyMaxCount = pixCount;
tallyMaxIndex = i;
}
}
float percentage = initialConfidence * (tallyMaxCount * 100 / pixels);
Log.i(TAG, "Color of currency note: " + colors[tallyMaxIndex] + " (" + percentage + "% confidence).");
}
return mRgba;
}
private String getPixelColorType(int H, int S, int V)
{
String color;
if (V < 75)
color = "cBLACK";
else if (V > 190 && S < 27)
color = "cWHITE";
else if (S < 53 && V < 185)
color = "cGREY";
else { // Is a color
if (H < 14)
color = "cRED";
else if (H < 25)
color = "cORANGE";
else if (H < 34)
color = "cYELLOW";
else if (H < 73)
color = "cGREEN";
else if (H < 102)
color = "cAQUA";
else if (H < 127)
color = "cBLUE";
else if (H < 149)
color = "cPURPLE";
else if (H < 175)
color = "cPINK";
else // full circle
color = "cRED"; // back to Red
}
return color;
}
Thank you very much.
OpenCV has an Histogram method which counts all image colors. After the histogram is calculated all you would have to do is to chose the one with the biggest count...
Check here for a tutorial (C++): Histogram Calculation.
You might also the this stackoverflow answer which shows an example on how to use Android's histogram function Imgproc.calcHist().
Think about to resize your images, then you may multiply the results by the same scale:
resize( larg_image, smallerImage , interpolation=cv.CV_INTER_CUBIC );
Or,
you may check these solutions:
You could find dominant color using k-mean clustering method.
this link will be useful.
https://www.youtube.com/watch?v=f54-x3PckH8

Android Toast in iPhone?

When I write Android apps, I love the Toast feature. Is there a way to get this kind of set and forget popup message in iPhone development using MonoTouch (C# .NET)?
MonoTouch Toast Version here. Inspired by Android.
To call it,
ToastView t = new ToastView ("Email Sent", 1000);
t.Show ();
Enum File:
public enum ToastGravity
{
Top = 0,
Bottom = 1,
Center = 2
}
ToastSettings File:
using System;
using System.Drawing;
using MonoTouch.UIKit;
namespace General
{
public class ToastSettings
{
public ToastSettings ()
{
this.Duration = 500;
this.Gravity = ToastGravity.Center;
}
public int Duration
{
get;
set;
}
public double DurationSeconds
{
get { return (double) Duration/1000 ;}
}
public ToastGravity Gravity
{
get;
set;
}
public PointF Position
{
get;
set;
}
}
}
Main Toast Class:
using System;
using MonoTouch.Foundation;
using MonoTouch.UIKit;
using System.Drawing;
using MonoTouch.ObjCRuntime;
namespace General
{
public class ToastView : NSObject
{
ToastSettings theSettings = new ToastSettings ();
private string text = null;
UIView view;
public ToastView (string Text, int durationMilliseonds)
{
text = Text;
theSettings.Duration = durationMilliseonds;
}
int offsetLeft = 0;
int offsetTop = 0;
public ToastView SetGravity (ToastGravity gravity, int OffSetLeft, int OffSetTop)
{
theSettings.Gravity = gravity;
offsetLeft = OffSetLeft;
offsetTop = OffSetTop;
return this;
}
public ToastView SetPosition (PointF Position)
{
theSettings.Position = Position;
return this;
}
public void Show ()
{
UIButton v = UIButton.FromType (UIButtonType.Custom);
view = v;
UIFont font = UIFont.SystemFontOfSize (16);
SizeF textSize = view.StringSize (text, font, new SizeF (280, 60));
UILabel label = new UILabel (new RectangleF (0, 0, textSize.Width + 5, textSize.Height + 5));
label.BackgroundColor = UIColor.Clear;
label.TextColor = UIColor.White;
label.Font = font;
label.Text = text;
label.Lines = 0;
label.ShadowColor = UIColor.DarkGray;
label.ShadowOffset = new SizeF (1, 1);
v.Frame = new RectangleF (0, 0, textSize.Width + 10, textSize.Height + 10);
label.Center = new PointF (v.Frame.Size.Width / 2, v.Frame.Height / 2);
v.AddSubview (label);
v.BackgroundColor = UIColor.FromRGBA (0, 0, 0, 0.7f);
v.Layer.CornerRadius = 5;
UIWindow window = UIApplication.SharedApplication.Windows[0];
PointF point = new PointF (window.Frame.Size.Width / 2, window.Frame.Size.Height / 2);
if (theSettings.Gravity == ToastGravity.Top)
{
point = new PointF (window.Frame.Size.Width / 2, 45);
}
else if (theSettings.Gravity == ToastGravity.Bottom)
{
point = new PointF (window.Frame.Size.Width / 2, window.Frame.Size.Height - 45);
}
else if (theSettings.Gravity == ToastGravity.Center)
{
point = new PointF (window.Frame.Size.Width / 2, window.Frame.Size.Height / 2);
}
else
{
point = theSettings.Position;
}
point = new PointF (point.X + offsetLeft, point.Y + offsetTop);
v.Center = point;
window.AddSubview (v);
v.AllTouchEvents += delegate { HideToast (null); };
NSTimer.CreateScheduledTimer (theSettings.DurationSeconds, HideToast);
}
void HideToast ()
{
UIView.BeginAnimations ("");
view.Alpha = 0;
UIView.CommitAnimations ();
}
void RemoveToast ()
{
view.RemoveFromSuperview ();
}
}
}
Check this out:
https://github.com/ecstasy2/toast-notifications-ios
Edit: The project has moved to github so i update the link.
Here's my version: http://github.com/scalessec/toast
I think it's simpler to use because it's implemented as a obj-c category, thereby adding the makeToast methods to any instance of UIView. eg:
[self.view makeToast:#"This is some message as toast."
duration:3.0
position:#"bottom"];
Are you looking for something like UIAlertView?
You can use this link for objective-c code for Toast
http://code.google.com/p/toast-notifications-ios/source/browse/trunk/
While this link for its usage
http://code.google.com/p/toast-notifications-ios/wiki/HowToUse
which could be like any one of the below samples
[[iToast makeText:NSLocalizedString(#"The activity has been successfully saved.", #"")] show];
[[[iToast makeText:NSLocalizedString(#"The activity has been successfully saved.", #"")]
setGravity:iToastGravityBottom] show];
[[[[iToast makeText:NSLocalizedString(#"Something to display a very long time", #"")]
etGravity:iToastGravityBottom] setDuration:iToastDurationLong] show];
You might be after Local Notifications, pretty sure they allow you to set a time, I think in epoch time to be fired off. Don't think there is a way to hide them though. I might be misunderstanding your question though cause I'm unfamiliar with Toast.
Just You can use the following code with uilabel and uianimation to get toast like in android.
It does two works one is toast task and it increases the height of the label according to the text length with wordwrap IOS 7 later link here
CGRect initialFrame = CGRectMake(20, self.view.frame.size.height/2,300, 40);
NSString *message=#"Toast in Iphone as in Android";
UILabel *flashLabel=[[UILabel alloc] initWithFrame:initialFrame];
flashLabel.font=[UIFont fontWithName:#"Optima-Italic" size:12.0];
flashLabel.backgroundColor=[UIColor whiteColor];
flashLabel.layer.cornerRadius=3.0f;
flashLabel.numberOfLines=0;
flashLabel.textAlignment=NSTextAlignmentCenter;
CGSize maxSize = CGSizeMake(flashLabel.frame.size.width, MAXFLOAT);
CGRect labelRect = [message boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:#{NSFontAttributeName:flashLabel.font} context:nil];
//adjust the label the the new height.
CGRect newFrame = flashLabel.frame;
newFrame.size.height = labelRect.size.height;
flashLabel.frame = newFrame;
flashLabel.text=message;
[self.view addSubview:flashLabel];
flashLabel.alpha=1.0;
self.view.userInteractionEnabled=FALSE;
[UIView animateWithDuration:13.0 animations:^
{
flashLabel.alpha=0.0f;
}
completion:^(BOOL finished)
{
self.view.userInteractionEnabled=TRUE;
[flashLabel removeFromSuperview];
}];
I modified John's answer as follows:
Toast.h
#interface Toast : NSObject
+ (void)toast:(NSString *)message
:(UIView *) view
:(int)delay;
#end
Toast.m
#import "Toast.h"
#interface Toast ()
#end
#implementation Toast
+ (void)toast:(NSString *)message
:(UIView *) view
:(int)delay
{
CGRect initialFrame = CGRectMake(10, view.frame.size.height/2, 300, 40);
UILabel *flashLabel=[[UILabel alloc] initWithFrame:initialFrame];
flashLabel.font=[UIFont fontWithName:#"Optima-Italic" size:19.0];
flashLabel.backgroundColor=[UIColor whiteColor];
flashLabel.layer.cornerRadius=9.0f;
flashLabel.clipsToBounds = YES;
flashLabel.numberOfLines=3;
flashLabel.textAlignment=NSTextAlignmentCenter;
CGSize maxSize = CGSizeMake(flashLabel.frame.size.width, MAXFLOAT);
CGRect labelRect = [message boundingRectWithSize:maxSize
options:NSStringDrawingUsesLineFragmentOrigin
attributes:#{NSFontAttributeName:flashLabel.font}
context:nil];
//adjust the label the the new height.
CGRect newFrame = flashLabel.frame;
newFrame.size.height = labelRect.size.height * 2;
flashLabel.frame = newFrame;
flashLabel.text=message;
[view addSubview:flashLabel];
flashLabel.alpha=1.0;
view.userInteractionEnabled=FALSE;
[UIView animateWithDuration:delay animations:^
{
flashLabel.alpha=0.0f;
}
completion:^(BOOL finished)
{
view.userInteractionEnabled=TRUE;
[flashLabel removeFromSuperview];
}];
}
#end
I have added a little modification to the toast class that handles rotation of the display.
public void Show ()
{
UIButton v = UIButton.FromType (UIButtonType.Custom);
view = v;
UIFont font = UIFont.SystemFontOfSize (16);
SizeF textSize = view.StringSize (text, font, new SizeF (280, 60));
UILabel label = new UILabel (new RectangleF (0, 0, textSize.Width + 5, textSize.Height + 5));
label.BackgroundColor = UIColor.Clear;
label.TextColor = UIColor.White;
label.Font = font;
label.Text = text;
label.Lines = 0;
label.ShadowColor = UIColor.DarkGray;
label.ShadowOffset = new SizeF (1, 1);
v.Frame = new RectangleF (0, 0, textSize.Width + 10, textSize.Height + 10);
label.Center = new PointF (v.Frame.Size.Width / 2, v.Frame.Height / 2);
v.AddSubview (label);
v.BackgroundColor = UIColor.FromRGBA (0, 0, 0, 0.7f);
v.Layer.CornerRadius = 5;
UIWindow window = UIApplication.SharedApplication.Windows[0];
PointF point = new PointF (window.Frame.Size.Width / 2, window.Frame.Size.Height / 2);
if (theSettings.Gravity == ToastGravity.Top)
{
point = new PointF (window.Frame.Size.Width / 2, 45);
}
else if (theSettings.Gravity == ToastGravity.Bottom)
{
point = new PointF (window.Frame.Size.Width / 2, window.Frame.Size.Height - 45);
}
else if (theSettings.Gravity == ToastGravity.Center)
{
point = new PointF (window.Frame.Size.Width / 2, window.Frame.Size.Height / 2);
}
else
{
point = theSettings.Position;
}
point = new PointF (point.X + offsetLeft, point.Y + offsetTop);
v.Center = point;
//handle screen rotation
float orientation=0;
switch(UIApplication.SharedApplication.StatusBarOrientation)
{
case UIInterfaceOrientation.LandscapeLeft:
orientation=-90;
break;
case UIInterfaceOrientation.LandscapeRight:
orientation=90;
break;
case UIInterfaceOrientation.PortraitUpsideDown:
orientation=180;
break;
}
v.Transform=CGAffineTransform.MakeRotation ((float)(orientation / 180f * Math.Pi));
window.AddSubview (v);
v.AllTouchEvents += delegate { HideToast (); };
NSTimer.CreateScheduledTimer (theSettings.DurationSeconds, HideToast);
}
You could try my open source library TSMessages: https://github.com/toursprung/TSMessages
It's really easy to use and looks beautiful on iOS 5/6 and on iOS 7 as well.
I really like MonoTouch solution proposed by Bahai.
The following is not a substitution. Is just a ready-to-go one method the worked for me.
private async Task ShowToast(string message, UIAlertView toast = null)
{
if (null == toast)
{
toast = new UIAlertView(null, message, null, null, null);
toast.Show();
await Task.Delay(2000);
await ShowToast(message, toast);
return;
}
UIView.BeginAnimations("");
toast.Alpha = 0;
UIView.CommitAnimations();
toast.DismissWithClickedButtonIndex(0, true);
}
If the method is called from a background thread (not the main UI thread) then BeginInvokeOnMainThread is required which means just call it like this.
BeginInvokeOnMainThread(() =>
{
ShowToast(message);
});
I created a new repo on github with a class to do iOS toast-style alerts. I didn't like the one on code.google.com, it didn't rotate properly and wasn't pretty.
https://github.com/esilverberg/ios-toast
Enjoy folks.

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