1、setMouseCallback函數

用于創建鼠標響應函數

調用形式：

C++:?void?setMouseCallback(const string&?winname, MouseCallback?onMouse, void*?userdata=0?)

const string&?winname：窗口名稱

MouseCallback?onMouse：鼠標響應調用的函數

void*?userdata=0:一般選擇默認0

2、opencv例子：

程序如下，已經附上說明：

[cpp]?view plaincopy

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

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

#include?<stdio.h>??

??

using?namespace?cv;??

??

cv::Mat?org,dst,img,tmp;??

void?on_mouse(int?event,int?x,int?y,int?flags,void?*ustc)//event鼠標事件代號，x,y鼠標坐標，flags拖拽和鍵盤操作的代號??

{??

????static?Point?pre_pt?=?(-1,-1);//初始坐標??

????static?Point?cur_pt?=?(-1,-1);//實時坐標??

????char?temp[16];??

????if?(event?==?CV_EVENT_LBUTTONDOWN)//左鍵按下，讀取初始坐標，并在圖像上該點處劃圓??

????{??

????????org.copyTo(img);//將原始圖片復制到img中??

????????sprintf(temp,"(%d,%d)",x,y);??

????????pre_pt?=?Point(x,y);??

????????putText(img,temp,pre_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255),1,8);//在窗口上顯示坐標??

????????circle(img,pre_pt,2,Scalar(255,0,0,0),CV_FILLED,CV_AA,0);//劃圓??

????????imshow("img",img);??

????}??

????else?if?(event?==?CV_EVENT_MOUSEMOVE?&&?!(flags?&?CV_EVENT_FLAG_LBUTTON))//左鍵沒有按下的情況下鼠標移動的處理函數??

????{??

????????img.copyTo(tmp);//將img復制到臨時圖像tmp上，用于顯示實時坐標??

????????sprintf(temp,"(%d,%d)",x,y);??

????????cur_pt?=?Point(x,y);??

????????putText(tmp,temp,cur_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255));//只是實時顯示鼠標移動的坐標??

????????imshow("img",tmp);??

????}??

????else?if?(event?==?CV_EVENT_MOUSEMOVE?&&?(flags?&?CV_EVENT_FLAG_LBUTTON))//左鍵按下時，鼠標移動，則在圖像上劃矩形??

????{??

????????img.copyTo(tmp);??

????????sprintf(temp,"(%d,%d)",x,y);??

????????cur_pt?=?Point(x,y);??

????????putText(tmp,temp,cur_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255));??

????????rectangle(tmp,pre_pt,cur_pt,Scalar(0,255,0,0),1,8,0);//在臨時圖像上實時顯示鼠標拖動時形成的矩形??

????????imshow("img",tmp);??

????}??

????else?if?(event?==?CV_EVENT_LBUTTONUP)//左鍵松開，將在圖像上劃矩形??

????{??

????????org.copyTo(img);??

????????sprintf(temp,"(%d,%d)",x,y);??

????????cur_pt?=?Point(x,y);??

????????putText(img,temp,cur_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255));??

????????circle(img,pre_pt,2,Scalar(255,0,0,0),CV_FILLED,CV_AA,0);??

????????rectangle(img,pre_pt,cur_pt,Scalar(0,255,0,0),1,8,0);//根據初始點和結束點，將矩形畫到img上??

????????imshow("img",img);??

????????img.copyTo(tmp);??

????????//截取矩形包圍的圖像，并保存到dst中??

????????int?width?=?abs(pre_pt.x?-?cur_pt.x);??

????????int?height?=?abs(pre_pt.y?-?cur_pt.y);??

????????if?(width?==?0?||?height?==?0)??

????????{??

????????????printf("width?==?0?||?height?==?0");??

????????????return;??

????????}??

????????dst?=?org(Rect(min(cur_pt.x,pre_pt.x),min(cur_pt.y,pre_pt.y),width,height));??

????????namedWindow("dst");??

????????imshow("dst",dst);??

????????waitKey(0);??

????}??

}??

void?main()??

{??

????org?=?imread("1.jpg");??

????org.copyTo(img);??

????org.copyTo(tmp);??

????namedWindow("img");//定義一個img窗口??

????setMouseCallback("img",on_mouse,0);//調用回調函數??

????imshow("img",img);??

????cv::waitKey(0);??

} ?

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