如何在Linux中读取低级鼠标单击位置. [英] How to read low level mouse click position in linux .

问题描述

我正在使用此代码从linux中的dev/input/event *读取鼠标事件.

I am using this code to read mouse events from the dev/input/event* in linux .

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <linux/input.h>
#include <fcntl.h>

#define MOUSEFILE "/dev/input/event4"

int main()
{
    int fd;
    struct input_event ie;

    if((fd = open(MOUSEFILE, O_RDONLY)) == -1) {
        perror("opening device");
        exit(EXIT_FAILURE);
    }

    while(read(fd, &ie, sizeof(struct input_event))) {
        printf("time %ld.%06ld\ttype %d\tcode %d\tvalue %d\n",
               ie.time.tv_sec, ie.time.tv_usec, ie.type, ie.code, ie.value);

}
    return 0;
}

它以以下格式提供结果:

It gives me the results in the format :

时间1342517261.840285类型2代码0值-1

time 1342517261.840285 type 2 code 0 value -1

时间"是时间戳，它返回事件发生的时间.

'time' is the timestamp, it returns the time at which the event happened.

'code'是事件代码，例如REL_X或KEY_BACKSPACE，完整 列表在include/linux/input.h中.

'code' is event code, for example REL_X or KEY_BACKSPACE, complete list is in include/linux/input.h.

值"是事件携带的值.相对变化 EV_REL，EV_ABS(操纵杆...)的绝对新值，或EV_KEY的绝对新值 释放，1代表按键，2代表自动重复.

'value' is the value the event carries. Either a relative change for EV_REL, absolute new value for EV_ABS (joysticks ...), or 0 for EV_KEY for release, 1 for keypress and 2 for autorepeat.

当我单击时，我得到了事件，但没有获得鼠标在屏幕上的位置，如何在屏幕上获得鼠标的位置.

所以事实证明我必须使用相对坐标来获取鼠标坐标.我相信这是一个普遍的要求，因此可能存在可以使用的库/预先存在的代码得到坐标.关于该主题的任何信息都将非常有用.

Edit 1:So as it turns out that i have to use the relative co-ordinates to get the mouse co-ordinates .I believe this is a common requirement so there might be libraries/pre-existing code that you can use to get the co-ordinates. Any info on this topic will be very useful .

Edit2:解决方案

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <linux/input.h>
#include <fcntl.h>
#include <X11/Xlib.h>

#define MOUSEFILE "/dev/input/event4"

int main()
{
  int fd;
  struct input_event ie;
  Display *dpy;
  Window root, child;
  int rootX, rootY, winX, winY;
  unsigned int mask;

  dpy = XOpenDisplay(NULL);
  XQueryPointer(dpy,DefaultRootWindow(dpy),&root,&child,
              &rootX,&rootY,&winX,&winY,&mask);

  if((fd = open(MOUSEFILE, O_RDONLY)) == -1) {
    perror("opening device");
    exit(EXIT_FAILURE);
  }

  while(read(fd, &ie, sizeof(struct input_event))) {
    if (ie.type == 2) {
      if (ie.code == 0) {
          XQueryPointer(dpy,DefaultRootWindow(dpy),&root,&child,
                        &rootX,&rootY,&winX,&winY,&mask);
          //rootX += ie.value;
          }
      else if (ie.code == 1) {
          XQueryPointer(dpy,DefaultRootWindow(dpy),&root,&child,
                        &rootX,&rootY,&winX,&winY,&mask);
         // rootY += ie.value;
          }
      printf("time%ld.%06ld\tx %d\ty %d\n",
         ie.time.tv_sec, ie.time.tv_usec, rootX, rootY);
    } else
      printf("time %ld.%06ld\ttype %d\tcode %d\tvalue %d\n",
          ie.time.tv_sec, ie.time.tv_usec, ie.type, ie.code, ie.value);
  }
  return 0;
}

XQueryPointer似乎是更方便的解决方案.谢谢@perreal的指导.

XQueryPointer seems more convenient solution . Thanks , @perreal for the guidance .

推荐答案

您可以从X11获取初始位置，并使用相对坐标来跟踪指针:

You can get the initial position from X11, and use relative coordinates to track the pointer:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <linux/input.h>
#include <fcntl.h>
#include <X11/Xlib.h>

#define MOUSEFILE "/dev/input/event6"

int main()
{
  int fd;
  struct input_event ie;
  Display *dpy;
  Window root, child;
  int rootX, rootY, winX, winY;
  unsigned int mask;

  dpy = XOpenDisplay(NULL);
  XQueryPointer(dpy,DefaultRootWindow(dpy),&root,&child,
              &rootX,&rootY,&winX,&winY,&mask); 

  if((fd = open(MOUSEFILE, O_RDONLY)) == -1) {
    perror("opening device");
    exit(EXIT_FAILURE);
  }

  while(read(fd, &ie, sizeof(struct input_event))) {
    if (ie.type == 2) {
      if (ie.code == 0) { rootX += ie.value; }
      else if (ie.code == 1) { rootY += ie.value; }
      printf("time%ld.%06ld\tx %d\ty %d\n", 
         ie.time.tv_sec, ie.time.tv_usec, rootX, rootY);
    } else if (ie.type == 1) {
      if (ie.code == 272 ) { 
        printf("Mouse button ");
        if (ie.value == 0)  
          printf("released!!\n");
        if (ie.value == 1)  
          printf("pressed!!\n");
    } else {
        printf("time %ld.%06ld\ttype %d\tcode %d\tvalue %d\n",
            ie.time.tv_sec, ie.time.tv_usec, ie.type, ie.code, ie.value);
    }
  }
  return 0;
}

这篇关于如何在Linux中读取低级鼠标单击位置.的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！