update samples: waitKey() usage

Original commit is a5f19f7dd6ae5bc93f73e0417a9e0bfd34c01672

samples/cpp/tutorial_code/ImgProc/Pyramids.cpp

@@ -45,26 +45,22 @@ int main( void )
   //![infinite_loop]
   for(;;)
   {
-    int c;
-    c = waitKey(0);
+    char c = (char)waitKey(0);
 
-    if( (char)c == 27 )
+    if( c == 27 )
       { break; }
-    if( (char)c == 'u' )
-      {
-        //![pyrup]
-        pyrUp( tmp, dst, Size( tmp.cols*2, tmp.rows*2 ) );
-        //![pyrup]
+    //![pyrup]
+    if( c == 'u' )
+      { pyrUp( tmp, dst, Size( tmp.cols*2, tmp.rows*2 ) );
         printf( "** Zoom In: Image x 2 \n" );
       }
-    else if( (char)c == 'd' )
-      {
-        //![pyrdown]
-        pyrDown( tmp, dst, Size( tmp.cols/2, tmp.rows/2 ) );
-        //![pyrdown]
+    //![pyrup]
+    //![pyrdown]
+    else if( c == 'd' )
+      { pyrDown( tmp, dst, Size( tmp.cols/2, tmp.rows/2 ) );
         printf( "** Zoom Out: Image / 2 \n" );
       }
-
+    //![pyrdown]
     imshow( window_name, dst );
 
     //![update_tmp]

samples/cpp/tutorial_code/ImgProc/Threshold.cpp

@@ -60,9 +60,8 @@ int main( int, char** argv )
   /// Wait until user finishes program
   for(;;)
     {
-      int c;
-      c = waitKey( 20 );
-      if( (char)c == 27 )
+      char c = (char)waitKey( 20 );
+      if( c == 27 )
     { break; }
     }
 

samples/cpp/tutorial_code/ImgProc/Threshold_inRange.cpp

@@ -41,7 +41,7 @@ int main()
     createTrackbar("Low B","Object Detection", &low_b, 255, on_low_b_thresh_trackbar);
     createTrackbar("High B","Object Detection", &high_b, 255, on_high_b_thresh_trackbar);
     //! [trackbar]
-    while(char(waitKey(1))!='q'){
+    while((char)waitKey(1)!='q'){
         //! [while]
         cap>>frame;
         if(frame.empty())

samples/cpp/tutorial_code/ImgTrans/HoughCircle_Demo.cpp

@@ -90,7 +90,7 @@ int main(int argc, char** argv)
     // infinite loop to display
     // and refresh the content of the output image
     // until the user presses q or Q
-    int key = 0;
+    char key = 0;
     while(key != 'q' && key != 'Q')
     {
         // those paramaters cannot be =0
@@ -102,7 +102,7 @@ int main(int argc, char** argv)
         HoughDetection(src_gray, src, cannyThreshold, accumulatorThreshold);
 
         // get user key
-        key = waitKey(10);
+        key = (char)waitKey(10);
     }
 
     return 0;

samples/cpp/tutorial_code/ImgTrans/Remap_Demo.cpp

@@ -40,9 +40,9 @@ int main( int, char** argv )
   for(;;)
   {
     /// Each 1 sec. Press ESC to exit the program
-    int c = waitKey( 1000 );
+    char c = (char)waitKey( 1000 );
 
-    if( (char)c == 27 )
+    if( c == 27 )
       { break; }
 
     /// Update map_x & map_y. Then apply remap

samples/cpp/tutorial_code/ImgTrans/copyMakeBorder_demo.cpp

@@ -23,9 +23,6 @@ RNG rng(12345);
  */
 int main( int, char** argv )
 {
-
-  int c;
-
   //![load]
   src = imread( argv[1], IMREAD_COLOR ); // Load an image
 
@@ -59,13 +56,12 @@ int main( int, char** argv )
   for(;;)
        {
          //![check_keypress]
-         c = waitKey(500);
-
-         if( (char)c == 27 )
+         char c = (char)waitKey(500);
+         if( c == 27 )
            { break; }
-         else if( (char)c == 'c' )
+         else if( c == 'c' )
            { borderType = BORDER_CONSTANT; }
-         else if( (char)c == 'r' )
+         else if( c == 'r' )
            { borderType = BORDER_REPLICATE; }
          //![check_keypress]
 

samples/cpp/tutorial_code/ImgTrans/filter2D_demo.cpp

@@ -25,8 +25,6 @@ int main ( int, char** argv )
   int kernel_size;
   const char* window_name = "filter2D Demo";
 
-  int c;
-
   //![load]
   src = imread( argv[1], IMREAD_COLOR ); // Load an image
 
@@ -45,9 +43,9 @@ int main ( int, char** argv )
   int ind = 0;
   for(;;)
        {
-         c = waitKey(500);
+         char c = (char)waitKey(500);
          /// Press 'ESC' to exit the program
-         if( (char)c == 27 )
+         if( c == 27 )
            { break; }
 
          //![update_kernel]

samples/cpp/tutorial_code/calib3d/real_time_pose_estimation/src/main_detection.cpp

@@ -180,7 +180,7 @@ int main(int argc, char *argv[])
 
   Mat frame, frame_vis;
 
-  while(cap.read(frame) && waitKey(30) != 27) // capture frame until ESC is pressed
+  while(cap.read(frame) && (char)waitKey(30) != 27) // capture frame until ESC is pressed
   {
 
     frame_vis = frame.clone();    // refresh visualisation frame

samples/cpp/tutorial_code/features2D/AKAZE_tracking/planar_tracking.cpp

@@ -195,7 +195,7 @@ int main(int argc, char **argv)
         drawStatistics(orb_res, orb_draw_stats);
         vconcat(akaze_res, orb_res, res_frame);
         cv::imshow(video_name, res_frame);
-        if(cv::waitKey(1)==27) break; //quit on ESC button
+        if(waitKey(1)==27) break; //quit on ESC button
     }
     akaze_stats /= i - 1;
     orb_stats /= i - 1;

samples/cpp/tutorial_code/objectDetection/objectDetection.cpp

@@ -44,8 +44,8 @@ int main( void )
         //-- 3. Apply the classifier to the frame
         detectAndDisplay( frame );
 
-        int c = waitKey(10);
-        if( (char)c == 27 ) { break; } // escape
+        char c = (char)waitKey(10);
+        if( c == 27 ) { break; } // escape
     }
     return 0;
 }

samples/cpp/tutorial_code/objectDetection/objectDetection2.cpp

@@ -51,8 +51,8 @@ int main( void )
         detectAndDisplay( frame );
 
         //-- bail out if escape was pressed
-        int c = waitKey(10);
-        if( (char)c == 27 ) { break; }
+        char c = (char)waitKey(10);
+        if( c == 27 ) { break; }
     }
     return 0;
 }

samples/cpp/tutorial_code/photo/seamless_cloning/cloning_gui.cpp

@@ -452,7 +452,7 @@ int main()
 
     for(;;)
     {
-        char key = (char) waitKey(0);
+        char key = (char)waitKey(0);
 
         if(key == 'd' && flag3 == 0)
         {

samples/cpp/tutorial_code/video/bg_sub.cpp

@@ -23,7 +23,7 @@ using namespace std;
 Mat frame; //current frame
 Mat fgMaskMOG2; //fg mask fg mask generated by MOG2 method
 Ptr<BackgroundSubtractor> pMOG2; //MOG2 Background subtractor
-int keyboard; //input from keyboard
+char keyboard; //input from keyboard
 
 /** Function Headers */
 void help();
@@ -98,7 +98,8 @@ void processVideo(char* videoFilename) {
         exit(EXIT_FAILURE);
     }
     //read input data. ESC or 'q' for quitting
-    while( (char)keyboard != 'q' && (char)keyboard != 27 ){
+    keyboard = 0;
+    while( keyboard != 'q' && keyboard != 27 ){
         //read the current frame
         if(!capture.read(frame)) {
             cerr << "Unable to read next frame." << endl;
@@ -119,7 +120,7 @@ void processVideo(char* videoFilename) {
         imshow("Frame", frame);
         imshow("FG Mask MOG 2", fgMaskMOG2);
         //get the input from the keyboard
-        keyboard = waitKey( 30 );
+        keyboard = (char)waitKey( 30 );
     }
     //delete capture object
     capture.release();
@@ -139,7 +140,8 @@ void processImages(char* fistFrameFilename) {
     //current image filename
     string fn(fistFrameFilename);
     //read input data. ESC or 'q' for quitting
-    while( (char)keyboard != 'q' && (char)keyboard != 27 ){
+    keyboard = 0;
+    while( keyboard != 'q' && keyboard != 27 ){
         //update the background model
         pMOG2->apply(frame, fgMaskMOG2);
         //get the frame number and write it on the current frame
@@ -162,7 +164,7 @@ void processImages(char* fistFrameFilename) {
         imshow("Frame", frame);
         imshow("FG Mask MOG 2", fgMaskMOG2);
         //get the input from the keyboard
-        keyboard = waitKey( 30 );
+        keyboard = (char)waitKey( 30 );
         //search for the next image in the sequence
         ostringstream oss;
         oss << (frameNumber + 1);

samples/cpp/tutorial_code/videoio/video-input-psnr-ssim/video-input-psnr-ssim.cpp

@@ -44,7 +44,6 @@ int main(int argc, char *argv[])
     conv << argv[3] << endl << argv[4];       // put in the strings
     conv >> psnrTriggerValue >> delay;        // take out the numbers
 
-    char c;
     int frameNum = -1;          // Frame counter
 
     VideoCapture captRefrnc(sourceReference), captUndTst(sourceCompareWith);
@@ -126,7 +125,7 @@ int main(int argc, char *argv[])
         imshow(WIN_RF, frameReference);
         imshow(WIN_UT, frameUnderTest);
 
-        c = (char)waitKey(delay);
+        char c = (char)waitKey(delay);
         if (c == 27) break;
     }