Environment CentOS7
g++ (GCC) 4.8.5 20150623 (Red Hat 4.8.5-16) $ pkg-config --modversion opencv 2.4.13
Refer to "OpenCV Chinese Reference Manual"
Source code:
/*************************
*
* main.cpp
*
* Read in the picture and display 2018.05 in reverse color
*
* compile：g++ main.cpp `pkg-config --cflags --libs opencv`
*/
#include<stdlib.h>
#include<stdio.h>
#include<math.h>
#include<cv.h>
#include<highgui.h>
/* handle mouse events */
void mouseHandler(int event, int x, int y, int flags, void* param)
/*flags:
CV_EVENT_FLAG_CTRLKEY,
CV_EVENT_FLAG_SHIFTKEY,
CV_EVENT_FLAG_ALTKEY,
CV_EVENT_FLAG_LBUTTON,
CV_EVENT_FLAG_RBUTTON,
CV_EVENT_FLAG_MBUTTON*/
{
printf("%d,%d,%d,%d\n",event,x,y,flags);
switch(event){
/* left mouse button pressed */
case CV_EVENT_LBUTTONDOWN:
printf("Left button down\n");
break;
/* Left mouse button up */
case CV_EVENT_LBUTTONUP:
printf("Left button up\n");
break;
/*left mouse button*/
case CV_EVENT_LBUTTONDBLCLK:
printf("Left button DBLCLK\n");
break;
/* Right mouse button pressed */
case CV_EVENT_RBUTTONDOWN:
printf("Right button down\n");
break;
/*Right click on the mouse*/
case CV_EVENT_RBUTTONUP:
printf("Right button up\n");
break;
/*right click*/
case CV_EVENT_RBUTTONDBLCLK:
printf("Right button DBLCLK\n");
break;
/* Middle mouse button pressed */
case CV_EVENT_MBUTTONDOWN:
printf("Middle button down\n");
break;
/* Middle mouse button up*/
case CV_EVENT_MBUTTONUP:
printf("Middle button up\n");
break;
/* middle mouse button */
case CV_EVENT_MBUTTONDBLCLK:
printf("Middle button DBLCLK\n");
break;
/*Mouse move*/
case CV_EVENT_MOUSEMOVE:
printf("Mouse move\n");
}
}
/* Slider handler */
void trackbarHandler(int pos)
{
printf("Trackbar position: %d\n",pos);
}
int main(int argc,char**argv)
{
/*image variable*/
IplImage *img = 0;
int height, width, step, channels;
uchar *data;
int i, j, k;
if(argc<2){
printf("Usage: main <image-file-name>\n\7");
exit(0);
}
/*load image*/
img = cvLoadImage(argv[1]);
if(!img){
printf("Could not load image file: %s\n",argv[1]);
exit(0);
}
/*Get image parameters*/
height = img->height;
width = img->width;
step = img->widthStep;
channels= img->nChannels;
data = (uchar*)img->imageData;
/*display image*/
//cvShowImage("mainWin0",img);
printf("Processing a %dx%d image with %d channels\n",height,width,channels);
/* Create a window and automatically control the size */
cvNamedWindow("mainWin", CV_WINDOW_AUTOSIZE);
/*Control window size*/
cvMoveWindow("mainWin", 100, 100);
/* Process the image: do whatever you want with it */
for(i=0;i<height;i++)
for(j=0;j<width;j++)
for(k=0;k<channels;k++)
/*Invert color*/
data[i*step+j*channels+k]=255-data[i*step+j*channels+k];
/*display image*/
cvShowImage("mainWin", img );
/*mouse events*/
int mouseParam = 0;
cvSetMouseCallback("mainWin",mouseHandler,&mouseParam);
/*Keyboard events*/
int key;
while(1){
key = cvWaitKey(0);
printf("key=%d\n",key);
/*Esc == 27*/
if(key == 27)break;
switch(key){
case 'h':printf("press h\n");
break;
case 'a':printf("press a\n");
break;
case 'b':printf("press b\n");
break;
case 'c':printf("press c\n");
break;
case 'd':printf("press d\n");
break;
default: break;
}
}
/*Resize the window (resize according to the window name: only the window with this name is resized)*/
cvResizeWindow("mainWin",100,100);
/* handle slider events */
int trackbarVal = 25;
int maxVal = 200;
cvCreateTrackbar("bar1","mainWin",&trackbarVal, maxVal, trackbarHandler);
//Get the current slider position
int pos = cvGetTrackbarPos("bar1","mainWin");
printf("pos = %d\n",pos);
//Set the slider position
cvSetTrackbarPos("bar1","mainWin",25);
/* release this image */
cvReleaseImage(&img );
/*close the window*/
cvDestroyWindow("mainWin");
return 0;
}
Compile and run:
$g++ main.cpp `pkg-config --cflags --libs opencv` $ ./a.out wong.jpg Processing a 301x286 image with 3 channels Left button down Left button up Right button down Right button up Middle button down Middle button up key=97 press a key=98 press b key=99 press c key=27 pos = 25
Pictures used:
