Implement func setMouseCallback()

[SilentGopherLnx]

Trying to implement setMouseCallback() I have done version for one window. Can you fix it for any windows and commit?

1)highgui_gocv.h

typedef void (*mouse_callback)(int event, int x, int y, int flags, void* param);
void Window_SetMouseCallback(const char* winname, mouse_callback callback);

2)highgui.cpp

void Window_SetMouseCallback(const char* winname, mouse_callback callback) {
   cv::setMouseCallback(winname, callback, NULL);
}

3)NEW go-file

package gocv

/*
#include <stdlib.h>
#include "highgui_gocv.h"

extern void for_cgo_mouse_callback(int event, int x, int y, int flags);

static void InsideCGO_MouseCallback(char* winname) {
    void callback(int event, int x, int y, int flags, void* param) {
        for_cgo_mouse_callback(event, x, y, flags);
    };
    Window_SetMouseCallback(winname, callback);
}
*/
import "C"

type MouseCallback = func(event int, x int, y int, flags int)
var callb MouseCallback

func (w *Window) SetMouseCallback(callback MouseCallback) {
    cName := C.CString(w.name)
    C.InsideCGO_MouseCallback(cName)
    callb = callback
}

//export for_cgo_mouse_callback
func for_cgo_mouse_callback(event C.int, x C.int, y C.int, flags C.int) { // cName *C.char win C.int,
    callb(int(event), int(x), int(y), int(flags))
}

//MouseEventTypes
const EVENT_MOUSEMOVE = 0
const EVENT_LBUTTONDOWN = 1
const EVENT_RBUTTONDOWN = 2
const EVENT_MBUTTONDOWN = 3
const EVENT_LBUTTONUP = 4
const EVENT_RBUTTONUP = 5
const EVENT_MBUTTONUP = 6
const EVENT_LBUTTONDBLCLK = 7
const EVENT_RBUTTONDBLCLK = 8
const EVENT_MBUTTONDBLCLK = 9
const EVENT_MOUSEWHEEL = 10
const EVENT_MOUSEHWHEEL = 11

//MouseEventFlags
const EVENT_FLAG_LBUTTON = 1
const EVENT_FLAG_RBUTTON = 2
const EVENT_FLAG_MBUTTON = 4
const EVENT_FLAG_CTRLKEY = 8
const EVENT_FLAG_SHIFTKEY = 16
const EVENT_FLAG_ALTKEY = 32

Usage Example

w := gocv.NewWindow("test")
mouse_callback := func(event int, x int, y int, flags int) {
    if event == cv.EVENT_LBUTTONDOWN {
        Prln("mouse click at: " + I2S(x) + "," + I2S(y))
    }
}
w.SetMouseCallback(mouse_callback)

[netbrain]

relates to #603

[amlwwalker]

and then to be able to implement polygon area of interest like this https://www.programmersought.com/article/3449903953/