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2012-12-21T13:38:03.497
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<p>If it helps, here is my code for drawing rectangles on multiple sized video streams</p> <pre><code>#include "stdafx.h" #include "opencv2/imgproc/imgproc.hpp" #include "opencv2/highgui/highgui.hpp" #include <stdlib.h> #include <stdio.h> #include <iostream> #define SSTR( x ) dynamic_cast< std::ostringstream & >(( std::ostringstream() << std::dec << x ) ).str() using namespace std; using namespace cv; Rect box; //global structures needed for drawing bool drawing_box = false; struct mousecallbackstruct{ Mat* src; Mat* overlay; string windowname; }; Mat srcoverlay,smallsrcoverlay; //an overlay must be created for each window you want to draw on void onMouse(int event, int x, int y, int flags, void* param) //it seems the only way to use this is by keeping different globals for different windows - meaning you have to set up all thise ahead of time, and keep track of it and not mix/match windows/frames!! horrible design here. { cout << event; mousecallbackstruct mousestruct; mousestruct = *((mousecallbackstruct*)param); Mat* srcp = mousestruct.src; Mat* overlayp = mousestruct.overlay; // yeah, yeah, i use 7 lines where I could use 3, so sue me Mat src = *srcp; Mat overlay = *overlayp; if(!src.data){ cout << "your void * cast didn't work :(\n"; return; } switch( event ){ case CV_EVENT_MOUSEMOVE: if( drawing_box ){ box.width = x-box.x; box.height = y-box.y; } break; case CV_EVENT_LBUTTONDOWN: //start drawing drawing_box = true; box = cvRect( x, y, 0, 0 ); break; case CV_EVENT_LBUTTONDBLCLK: //double click to clear drawing_box = false; overlay.setTo(cv::Scalar::all(0)); //clear it break; case CV_EVENT_LBUTTONUP: //draw what we created with Lbuttondown drawing_box = false; if( box.width < 0 ){ box.x += box.width; box.width *= -1; } if( box.height < 0 ){ box.y += box.height; box.height *= -1; } rectangle( overlay, Point(box.x, box.y), Point(box.x+box.width,box.y+box.height),CV_RGB(100,200,100),4); //draw rectangle. You can change this to line or circle or whatever. Maybe with the Right mouse button. break; } } void iimshow(mousecallbackstruct* mystructp){ //this is where we add the text/drawing created in the mouse handler to the actual image (since mouse handler events do not coincide with the drawing events) mousecallbackstruct mystruct = *mystructp; //custom struct made for the mouse callback - very handy for other functions too Mat overlay, src; Mat* srcp = mystruct.src; Mat* overlayp = mystruct.overlay; src = *srcp; // yeah, yeah, i use 9 lines where I could use 3, so sue me overlay = *overlayp; string name = mystruct.windowname; Mat added,imageROI; try{ //cout << "tch:" << overlay.rows << "," << src.rows << ";" << overlay.cols << "," << src.cols << ";" << src.channels() << "," << overlay.channels() <<"," << src.type() << "," << overlay.type() << "\n"; if(overlay.data && overlay.rows == src.rows && overlay.cols == src.cols && overlay.channels() == src.channels()){ //basic error checking add(src,overlay,added); }else{ //try to resize it imageROI= overlay(Rect(0,0,src.cols,src.rows)); add(src,imageROI,added); } imshow(name,added);// the actual draw moment }catch(...){ //if resize didn't work then this should catch it and you can see what didn't match up cout << "Error. Mismatch:" << overlay.rows << "," << src.rows << ";" << overlay.cols << "," << src.cols << ";" << src.channels() << "," << overlay.channels() <<"," << src.type() << "," << overlay.type() << "\n"; imshow(name + "overlay",overlay); imshow(name+"source",src); } } int _tmain(int argc, _TCHAR* argv[]){ VideoCapture cap(0); // open the default camera if(!cap.isOpened()) { // check if we succeeded cout << "NO camera found \n"; return -1; } Mat src,smallsrc,overlay; cap >> src; //grab 1 frame to build our preliminary Mats and overlays srcoverlay.create(src.rows,src.cols,src.type()); //create overlays smallsrcoverlay.create(src.rows,src.cols,src.type()); srcoverlay.setTo(cv::Scalar::all(0)); //clear it smallsrcoverlay.setTo(cv::Scalar::all(0)); //clear it namedWindow( "smallsrc", CV_WINDOW_AUTOSIZE ); namedWindow( "source", CV_WINDOW_AUTOSIZE ); //these must be created early for the setmousecallback, AND you have to know what Mats will be using them and not switch them around :( moveWindow("smallsrc",1000,100); //create a small original capture off to the side of screen ////////////// for each window/mat that uses a mouse handler, you must create one of these structures for it and pass it into the mouse handler, and add a global mat for overlays (at top of code) mousecallbackstruct srcmousestruct,smallsrcmousestruct; //these get passed into the mouse callback function. Hopefully they update their contents automatically for the callback? :( srcmousestruct.overlay = &srcoverlay; //fill our custom struct srcmousestruct.src = &src; srcmousestruct.windowname = "source"; smallsrcmousestruct.overlay = &smallsrcoverlay; //the small window smallsrcmousestruct.src = &smallsrc; smallsrcmousestruct.windowname = "smallsrc"; setMouseCallback(smallsrcmousestruct.windowname, onMouse, (void*)&smallsrcmousestruct); //the actual 'set mouse callback' call setMouseCallback(srcmousestruct.windowname, onMouse, (void*)&srcmousestruct); for(;;){ //main loop /// Load an image cap >> src; if( !src.data ) { return -1; } resize(src,smallsrc,Size(),.5,.5); //smaller scale window of original overlay = *srcmousestruct.overlay; src = *srcmousestruct.src; iimshow(&srcmousestruct); //my imshow replacement. uses structs iimshow(&smallsrcmousestruct); if(waitKey(30) == 27) cin.get(); //esc pauses } cin.get(); return 0; } </code></pre>
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