拥有3m的microtouch显示器。它通过USB连接到我的debian系统,并重新识别为人机界面(hid)。我正在尝试访问和推送实时信息…如果被触摸,我想知道(x,y)的位置,并将其通过netcat通过管道传送到另一台主机。
不幸的是,我只能使用
cat /dev/input/event2 | hexdump
要么 evtest
evtest
您会得到似乎无处可查的十六进制代码…
有人知道如何获取这些信息吗?必须有一种从十六进制代码中提取它的方法。不幸的是,我不知道如何解释十六进制代码。我找不到它记录的任何来源…
内核可以通过某种方式实时向我提供这些所需信息吗?作为一个工作环境,也许有一个解决方案,X服务器可以告诉我什么?触摸屏的行为就像X中的鼠标。实际上,我已经准备好尝试通过xlib获取鼠标的x,y位置。但这太慢了,无法告诉我是否有人在触摸……
提前致谢!
evtest示例输出:
Event: time 1425319271.595631, type 3 (EV_ABS), code 57 (ABS_MT_TRACKING_ID), value 51 Event: time 1425319271.595631, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 10304 Event: time 1425319271.595631, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 30629 Event: time 1425319271.595631, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 893 Event: time 1425319271.595631, type 3 (EV_ABS), code 49 (ABS_MT_TOUCH_MINOR), value 414 Event: time 1425319271.595631, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 1 Event: time 1425319271.595631, type 3 (EV_ABS), code 0 (ABS_X), value 10304 Event: time 1425319271.595631, type 3 (EV_ABS), code 1 (ABS_Y), value 30629 Event: time 1425319271.595631, -------------- SYN_REPORT ------------ Event: time 1425319271.601632, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 10306 Event: time 1425319271.601632, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 30625 Event: time 1425319271.601632, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 962 Event: time 1425319271.601632, type 3 (EV_ABS), code 49 (ABS_MT_TOUCH_MINOR), value 421 Event: time 1425319271.601632, type 3 (EV_ABS), code 47 (ABS_MT_SLOT), value 1 Event: time 1425319271.601632, type 3 (EV_ABS), code 57 (ABS_MT_TRACKING_ID), value 52 Event: time 1425319271.601632, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 15416 Event: time 1425319271.601632, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 24159 Event: time 1425319271.601632, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 649 Event: time 1425319271.601632, type 3 (EV_ABS), code 49 (ABS_MT_TOUCH_MINOR), value 354 Event: time 1425319271.601632, type 3 (EV_ABS), code 0 (ABS_X), value 10306 Event: time 1425319271.601632, type 3 (EV_ABS), code 1 (ABS_Y), value 30625 Event: time 1425319271.601632, -------------- SYN_REPORT ------------ Event: time 1425319271.606626, type 3 (EV_ABS), code 47 (ABS_MT_SLOT), value 0 Event: time 1425319271.606626, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 10318 Event: time 1425319271.606626, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 30609 Event: time 1425319271.606626, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 1014 Event: time 1425319271.606626, type 3 (EV_ABS), code 49 (ABS_MT_TOUCH_MINOR), value 426 Event: time 1425319271.606626, type 3 (EV_ABS), code 47 (ABS_MT_SLOT), value 1 Event: time 1425319271.606626, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 24161 Event: time 1425319271.606626, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 681 Event: time 1425319271.606626, type 3 (EV_ABS), code 49 (ABS_MT_TOUCH_MINOR), value 376 Event: time 1425319271.606626, type 3 (EV_ABS), code 0 (ABS_X), value 10318 Event: time 1425319271.606626, type 3 (EV_ABS), code 1 (ABS_Y), value 30609 Event: time 1425319271.606626, -------------- SYN_REPORT ------------ Event: time 1425319271.611629, type 3 (EV_ABS), code 47 (ABS_MT_SLOT), value 0 Event: time 1425319271.611629, type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 10320 Event: time 1425319271.611629, type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 30605 Event: time 1425319271.611629, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 1053 Event: time 1425319271.611629, type 3 (EV_ABS), code 49 (ABS_MT_TOUCH_MINOR), value 430 Event: time 1425319271.611629, type 3 (EV_ABS), code 47 (ABS_MT_SLOT), value 1 Event: time 1425319271.611629, type 3 (EV_ABS), code 48 (ABS_MT_TOUCH_MAJOR), value 705 Event: time 1425319271.611629, type 3 (EV_ABS), code 49 (ABS_MT_TOUCH_MINOR), value 392 Event: time 1425319271.611629, type 3 (EV_ABS), code 0 (ABS_X), value 10320 Event: time 1425319271.611629, type 3 (EV_ABS), code 1 (ABS_Y), value 30605
您可以使用evtest工具获取解析的坐标。
如果仅需要单点触摸坐标:查找ABS_X和ABS_Y字段:
ABS_X
ABS_Y
type 3 (EV_ABS), code 0 (ABS_X), value 10306
type 3 (EV_ABS), code 1 (ABS_Y), value 30625
如果您需要多点触控坐标:
ABS_MT_SLOT
ABS_MT_POSITION_X
ABS_MT_POSITION_Y
手指#0:
type 3 (EV_ABS), code 47 (ABS_MT_SLOT), value 0 type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 10318 type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 30609
手指#1:
type 3 (EV_ABS), code 47 (ABS_MT_SLOT), value 1 type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 20301 type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 24161
例如,如果您需要通过网络发送单点触摸坐标,则可以使用如下脚本:
#!/bin/sh # ---- Global variables ---- input=/dev/input/event0 code_prefix="ABS" code="${code_prefix}_[XY]" val_regex=".*(${code_prefix}_\(.\)), value \([-]\?[0-9]\+\)" val_subst="\1=\2" # ---- Functions ---- send_axis() { # 1. Convert axis value ($1) from device specific units # 2. Send this axis value via UDP packet echo $1 } process_line() { while read line; do axis=$(echo $line | grep "^Event:" | grep $code | \ sed "s/$val_regex/$val_subst/") if [ -n "$axis" ]; then send_axis $axis fi done } # ---- Entry point ---- if [ $(id -u) -ne 0 ]; then echo "This script must be run from root" >&2 exit 1 fi evtest $input | process_line
您可以编写将读取事件文件的C应用程序。获得的二进制数据很容易解释,请参阅内核文档中的第5节。您可以使用select()syscall 等待下一个数据部分。
select()
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <linux/input.h> #define EVENT_DEVICE "/dev/input/event2" #define EVENT_TYPE EV_ABS #define EVENT_CODE_X ABS_X #define EVENT_CODE_Y ABS_Y /* TODO: Close fd on SIGINT (Ctrl-C), if it's open */ int main(int argc, char *argv[]) { struct input_event ev; int fd; char name[256] = "Unknown"; if ((getuid ()) != 0) { fprintf(stderr, "You are not root! This may not work...\n"); return EXIT_SUCCESS; } /* Open Device */ fd = open(EVENT_DEVICE, O_RDONLY); if (fd == -1) { fprintf(stderr, "%s is not a vaild device\n", EVENT_DEVICE); return EXIT_FAILURE; } /* Print Device Name */ ioctl(fd, EVIOCGNAME(sizeof(name)), name); printf("Reading from:\n"); printf("device file = %s\n", EVENT_DEVICE); printf("device name = %s\n", name); for (;;) { const size_t ev_size = sizeof(struct input_event); ssize_t size; /* TODO: use select() */ size = read(fd, &ev, ev_size); if (size < ev_size) { fprintf(stderr, "Error size when reading\n"); goto err; } if (ev.type == EVENT_TYPE && (ev.code == EVENT_CODE_X || ev.code == EVENT_CODE_Y)) { /* TODO: convert value to pixels */ printf("%s = %d\n", ev.code == EVENT_CODE_X ? "X" : "Y", ev.value); } } return EXIT_SUCCESS; err: close(fd); return EXIT_FAILURE; }
首先,您需要了解以下内容:
[x=0;y=0]
通常可以在设备的驱动程序代码中找到此信息。
这是您设备的驱动程序。
因此,似乎您需要将轴值evtest除以65535,然后乘以设备的宽度或高度(以像素为单位)。例如,如果得到X = 30000,并且LCD面板的宽度为1080像素,则需要执行以下操作:
X = round((30000 / 65535) * 1080) = 494 pixels