Can we access camera and alarm clock on Android devices through Qt5.1.0 Android build?

[jiangcaiyang]

I am making an experiment on Qt5.1.0 Android build to test whether these functionalities are applicable through Qt, or can we find workaround ( ie. 3rd party library through C++ ) to meet these demand?

[stereomatching]

Qt5.1 do not support camera yet, you have to wait for Qt5.2 for full support. Qt5.1 is a technical preview only.

This blog has the answer you want
"Qt5.1 RC":http://blog.qt.digia.com/blog/2013/06/18/qt-5-1-release-candidate-available/

Maybe you could give openCV a try, it should be able to access the camera of android.

[jiangcaiyang]

[quote author="stereomatching" date="1371841980"]Qt5.1 do not support camera yet, you have to wait for Qt5.2 for full support. Qt5.1 is a technical preview only.

This blog has the answer you want
"Qt5.1 RC":http://blog.qt.digia.com/blog/2013/06/18/qt-5-1-release-candidate-available/

Maybe you could give openCV a try, it should be able to access the camera of android.

[/quote]
How about alarm clock? I've searched the Internet and find there is a service in controling Android internal alarm clock. How does Qt handle Android service? Thanks.
hey, stereomatching, are you the one who is active at CSDN Qt forum?

[stereomatching]

[quote author="jiangcaiyang" date="1371911455"]
How about alarm clock? I've searched the Internet and find there is a service in controling Android internal alarm clock. How does Qt handle Android service? Thanks.
[/quote]
Sorry, I don't know the answer

[quote author="jiangcaiyang" date="1371911455"]
hey, stereomatching, are you the one who is active at CSDN Qt forum?
[/quote]
Not sure who you are talking about, but I do have an account on CSDN.

[Moster]

Do you still need to access the camera or was that more like a general quesstion? I could provide an example project that uses opencv to access the camera

[stereomatching]

[quote author="Moster" date="1372151432"]Do you still need to access the camera or was that more like a general quesstion? I could provide an example project that uses opencv to access the camera[/quote]

Please show us your example, I tried it before on desktop, but haven't tried it on android yet.

.hpp
@
#ifndef OPENCVCAMERA_HPP
#define OPENCVCAMERA_HPP

#include <QQuickPaintedItem>
#include <QString>

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>

class QPainter;
class QTimer;

class openCVCamera : public QQuickPaintedItem
{
Q_OBJECT
Q_PROPERTY(int imageHeight READ imageHeight WRITE setImageHeight NOTIFY imageHeightChanged)
Q_PROPERTY(int imageWidth READ imageWidth WRITE setImageWidth NOTIFY imageWidthChanged)
Q_PROPERTY(bool play READ play WRITE setPlay NOTIFY playChanged)
public:
explicit openCVCamera(QQuickItem *parent = 0);
openCVCamera(openCVCamera const&)=delete;
openCVCamera& operator=(openCVCamera const&)=delete;

int imageHeight();
int imageWidth();

void paint(QPainter *painter);
bool play() const;

void setImageHeight(int value);
void setImageWidth(int value);
void setPlay(bool value);

signals:
void imageHeightChanged();
void imageWidthChanged();

void playChanged();

public slots:
void open(size_t index);

private slots:
void captureFrame();

private:
cv::VideoCapture camera_;
cv::Mat cameraFrame_;

cv::Mat displayedFrame_;

int imageHeight_;
int imageWidth_;

QString log_;

bool play_;

QTimer *timer_;

};

#endif // OPENCVCAMERA_HPP

@

.cpp
@
#include <QDebug>

#include <QPainter>
#include <QTimer>

#include <opencv2/core/core.hpp>

#include "openCVToQt.hpp"

#include "openCVCamera.hpp"

openCVCamera::openCVCamera(QQuickItem *parent) :
QQuickPaintedItem(parent), imageHeight_(320), imageWidth_(480), play_(false), timer_(new QTimer(this))
{
open(0);
setRenderTarget(QQuickPaintedItem::FramebufferObject);
setPerformanceHint(QQuickPaintedItem::FastFBOResizing);
camera_.set(CV_CAP_PROP_FRAME_WIDTH, 480);
camera_.set(CV_CAP_PROP_FRAME_HEIGHT, 320);
//setRenderTarget(QQuickPaintedItem::Image);

connect(timer_, &QTimer::timeout, this, &openCVCamera::captureFrame);
timer_->start(33);

}

int openCVCamera::imageHeight()
{
return imageHeight_;
}

int openCVCamera::imageWidth()
{
return imageWidth_;
}

void openCVCamera::open(size_t index)
{
camera_.open(index);
if(!camera_.isOpened()){
log_ = "could not access the camera or video";
qDebug() << log_;
}
}

void openCVCamera::paint(QPainter *painter)
{
if(cameraFrame_.empty()){
log_ = "could not grab the camera frame";
qDebug() << log_;
return;
}
cv::resize(cameraFrame_, cameraFrame_, cv::Size(imageWidth_, imageHeight_));
QImage const img = mat_to_qimage_ref(cameraFrame_);
painter->drawImage(0, 0, img);
}

bool openCVCamera::play() const
{
return play_;
}

void openCVCamera::setImageHeight(int value)
{
if(value != imageHeight()){
imageHeight_ = value;
qDebug()<<"height changed : "<<value;
emit imageHeightChanged();
}
}

void openCVCamera::setImageWidth(int value)
{
if(value != imageWidth()){
imageWidth_ = value;
qDebug()<<"width changed : "<<value;
emit imageWidthChanged();
}
}

void openCVCamera::setPlay(bool value)
{
if(value != play_){
play_ = value;

    emit playChanged();
}

}

/**********************************************************
****************** implementation ************************
**********************************************************/

void openCVCamera::captureFrame()
{
if(play_){
camera_ >> cameraFrame_;
if(cameraFrame_.empty()){
log_ = "could not grab the camera frame";
qDebug() << log_;
return;
}
update();
}
}
@

Whatever, the speed is slower than QtMultimedia

[Moster]

Its just a simple project to test if it works. I basically just extended some opencv example. Im using a tegra3 device. So I got a modified opencv version for the tegra3. You would need to adjust the pro file for your opencv version

I have to say that Im also pretty new to Qt :P

main.cpp
@#include <QApplication>
#include "Window.h"

int main(int argc, char** argv){
QApplication app (argc, argv);

Window window;
window.showMaximized();

return app.exec();

}
@

Window.cpp

@#include "Window.h"

Window::Window(QWidget *parent) :
QWidget(parent)
{
scene = new QGraphicsScene(this);

view = new QGraphicsView(scene, this);
view->setViewport(new QGLWidget);

//view->setFixedSize(640,480);
view->setScene(scene);
 view->showMaximized();

QThread* thread = new QThread;
Worker* worker = new Worker();
worker->moveToThread(thread);

connect(worker, SIGNAL(error(QString)), this, SLOT(errorString(QString)));
connect(thread, SIGNAL(started()), worker, SLOT(process()));
connect(worker, SIGNAL(finished()), thread, SLOT(quit()));
connect(worker, SIGNAL(finished()), worker, SLOT(deleteLater()));
connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
connect(worker, SIGNAL(sendPicture(QImage*, Mat*)), this, SLOT(updateScene(QImage*, Mat*)));
thread->start();

}

void Window::updateScene(QImage result, Mat help){

scene->clear();
scene->addPixmap(QPixmap::fromImage(*result));

delete(result);
delete(help);

}

Worker::Worker() {

 capture = new cv::VideoCapture(0);
 cv::Size camera_resolution;
 camera_resolution.width=640;
 camera_resolution.height=480;

 capture->set(CV_CAP_PROP_FRAME_WIDTH, camera_resolution.width);
 capture->set(CV_CAP_PROP_FRAME_HEIGHT, camera_resolution.height);

}

Worker::~Worker(){
capture->release();

}

void Worker::process(){

 float fps = 0;

  queue<int64> time_queue;

  while(1){
        int64 then;
        int64 now = cv::getTickCount();
        time_queue.push(now);

        // help = new Mat();
        drawing_frame = new Mat();
        if (!capture.empty())
        {

            if (capture->grab())
                capture->retrieve(*drawing_frame, CV_CAP_ANDROID_GREY_FRAME);


            char buffer[256];
            sprintf(buffer, "Display performance: %dx%d fps: %.3f", drawing_frame->cols, drawing_frame->rows, fps);           
            cv::putText(*drawing_frame, std::string(buffer), cv::Point(0,32), cv::FONT_HERSHEY_PLAIN, 0.75, cv::Scalar(0,255,0,255));
        }

        if (time_queue.size() >= 2)
            then = time_queue.front();
        else
            then = 0;

        if (time_queue.size() >= 25)
            time_queue.pop();

        fps = time_queue.size() * (float)cv::getTickFrequency() / (now-then);


        img = new QImage((uchar*)drawing_frame->data, drawing_frame->cols, drawing_frame->rows, drawing_frame->step,QImage::Format_Indexed8);


        emit sendPicture(img, drawing_frame);        


}

}
@

[Moster]

Window.h

@#ifndef WINDOW_H
#define WINDOW_H

#include "helper.h"

class QGraphicsView;
class QGraphicsScene;
class QGraphicsPixmapItem;

class Window : public QWidget
{
Q_OBJECT
public:
explicit Window(QWidget parent = 0);
public slots:
void updateScene(QImage img, Mat* help);
private:
QGraphicsView *view;
QGraphicsScene scene;
QGraphicsPixmapItem item;

};

class Worker : public QObject {
Q_OBJECT
cv::Ptrcv::VideoCapture capture;
QImage *img;
Mat *drawing_frame;
public:
Worker();
~Worker();

public slots:
void process();

signals:
void finished();
void error(QString err);
void sendPicture(QImage* img, Mat* help);
};

#endif // WINDOW_H@

helper.h

@#ifndef HELPER_H
#define HELPER_H
#define _USE_MATH_DEFINES

#include <math.h>
#include <jni.h>
#include <errno.h>
#include <sys/time.h>
#include <time.h>
#include <queue>
#include <vector>

#include <QGraphicsScene>
#include <QGraphicsView>
#include <QImage>
#include <QWidget>
#include <QObject>
#include <QThread>
#include <QPixmap>
#include <QGLWidget>

#include <android/log.h>

#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>

#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG,VA_ARGS)
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,VA_ARGS)
#define LOGW(...) __android_log_print(ANDROID_LOG_WARN,LOG_TAG,VA_ARGS)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,VA_ARGS)

using namespace std;
using namespace cv;

#endif // HELPER_H@

project file: cam.pro

@TEMPLATE = app
TARGET = cam

QT = opengl core widgets gui

OTHER_FILES +=
android/version.xml
android/src/org/qtproject/qt5/android/bindings/QtActivity.java
android/src/org/qtproject/qt5/android/bindings/QtApplication.java
android/src/org/kde/necessitas/ministro/IMinistro.aidl
android/src/org/kde/necessitas/ministro/IMinistroCallback.aidl
android/res/values-el/strings.xml
android/res/values-nb/strings.xml
android/res/values-zh-rCN/strings.xml
android/res/values-id/strings.xml
android/res/values-ja/strings.xml
android/res/values-zh-rTW/strings.xml
android/res/values-de/strings.xml
android/res/values-fr/strings.xml
android/res/values-pl/strings.xml
android/res/values-ro/strings.xml
android/res/values-it/strings.xml
android/res/values-es/strings.xml
android/res/values-pt-rBR/strings.xml
android/res/values-fa/strings.xml
android/res/layout/splash.xml
android/res/values-rs/strings.xml
android/res/values-ms/strings.xml
android/res/values-et/strings.xml
android/res/values/strings.xml
android/res/values/libs.xml
android/res/values-nl/strings.xml
android/res/values-ru/strings.xml
android/AndroidManifest.xml

INCLUDEPATH += $$PWD/../../../NVPACK/OpenCV-2.4.5-Tegra-sdk/sdk/native/jni/include/opencv/
INCLUDEPATH += $$PWD/../../../NVPACK/OpenCV-2.4.5-Tegra-sdk/sdk/native/jni/include/opencv2/
INCLUDEPATH += $$PWD/../../../NVPACK/OpenCV-2.4.5-Tegra-sdk/sdk/native/jni/include/
INCLUDEPATH += $$PWD/../../../NVPACK/android-ndk-r8d/sources/android/native_app_glue

LIBS += -L$$PWD/../../../NVPACK/android-ndk-r8d/platforms/android-14/arch-arm/usr/lib/ -landroid

INCLUDEPATH += $$PWD/../../../NVPACK/android-ndk-r8d/platforms/android-14/arch-arm/usr/include/android
DEPENDPATH += $$PWD/../../../NVPACK/android-ndk-r8d/platforms/android-14/arch-arm/usr/include/android

LIBS += -L$$PWD/../../../NVPACK/android-ndk-r8d/platforms/android-14/arch-arm/usr/lib/ -lEGL

INCLUDEPATH += $$PWD/../../../NVPACK/android-ndk-r8d/platforms/android-14/arch-arm/usr/include/EGL
DEPENDPATH += $$PWD/../../../NVPACK/android-ndk-r8d/platforms/android-14/arch-arm/usr/include/EGL

LIBS += -L$$PWD/../../../NVPACK/android-ndk-r8d/platforms/android-14/arch-arm/usr/lib/ -lGLESv2

INCLUDEPATH += $$PWD/../../../NVPACK/android-ndk-r8d/platforms/android-14/arch-arm/usr/include/GLES2
DEPENDPATH += $$PWD/../../../NVPACK/android-ndk-r8d/platforms/android-14/arch-arm/usr/include/GLES2

LIBS += -L$$PWD/../../../NVPACK/OpenCV-2.4.5-Tegra-sdk/sdk/native/libs/tegra3/
-lopencv_contrib
-lopencv_legacy
-lopencv_ml
-lopencv_stitching
-lopencv_objdetect
-lopencv_videostab
-lopencv_calib3d
-lopencv_photo
-lopencv_video
-lopencv_features2d
-lopencv_highgui
-lopencv_androidcamera
-lopencv_flann
-lopencv_imgproc
-lopencv_core

LIBS += -L$$PWD/../../../NVPACK/OpenCV-2.4.5-Tegra-sdk/sdk/native/3rdparty/libs/tegra3/
-ltbb
-llibjpeg
-llibpng
-llibtiff
-llibjasper
-lIlmImf

SOURCES +=
main.cpp
Window.cpp

HEADERS +=
helper.h
Window.h
@

[stereomatching]

Thanks for your codes:). Maybe you could use smart pointer
(unique_ptr) to guard your resources, this could make your codes
become safer and more robust(there are a lot of articles explain how
important smart pointer(RAII) in c++).

[Moster]

Thanks for the hint :) Im pretty new to c++, too.
So Im still learning stuff. Im going to check this out

[kybernetes]

what about alarm clock?