gnuplot分析touchscreen轨迹

gnuplot，顾名思义就是一个画平面图的软件，当然立体图也是可以画的。在Linux下，这是一个相当容易上手的画轨迹的软件。

之前做Touchscreen的时候，手指抬起来的时候坐标有时会乱飞，一直不知道为什么，我就想到用这个软件来把轨迹图画出来。

最终结果如下：

蓝色，紫色，红色的三段是实际的轨迹，但是绿色就是错误的坐标了，不知道是采样还是驱动的问题，总之错误的坐标是发上来了。

画图的脚本如下：

#!/usr/bin/gnuplot
set   autoscale                        # scale axes automatically
unset log                              # remove any log-scaling
unset label                            # remove any previous labels
set xtic auto                          # set xtics automatically
set ytic auto                          # set ytics automatically
set title "jitter"
set xlabel "x axis"
set ylabel "y axis"
set yrange [] reverse
plot    "log1" using ($1):($2) title 'log1' with linespoints ,"log2" using 1:2 title 'log2' with linespoints ,"log3" using 1:2 title 'log3' with linespoints ,"log4" using 1:2 title 'log4' with linespoints
#where <style> is either `lines`, `points`, `linespoints`, `impulses`, `dots`, `steps`, `fsteps`, `histeps`, `errorbars`, `labels`, `xerrorbars`, `yerrorbars`, `xyerrorbars`, `errorlines`, `xerrorlines`, `yerrorlines`, `xyerrorlines`, `boxes`, `histograms`, `filledcurves`, `boxerrorbars`, `boxxyerrorbars`, `financebars`, `candlesticks`, `vectors`, `image`, `rgbimage` or `pm3d`.

log1:

2707 3332
2732 3429
2754 3542
2779 3652
2803 3764
2824 3877
2841 3963
2852 4029
2863 4076
2866 4118
2867 4128
2867 4132
2866 4146
2866 4142
2869 4139
2868 4137
2871 4124
2872 4121
2870 4122
2869 4115
2869 4119
2868 4113
2869 4111
2869 4115
2866 4110
2867 4096
2889 4423

log2:

2889 4423
1351 4708
1364 1205
1352 1205

log3:

1352 1205
1404 1205
1352 1221
1404 1221
1350 1222
1350 1506
1350 1222
1364 1221
1352 1221
1350 1506
1350 1650
1352 1505
1350 1506
1352 1505
1350 1206
1352 1505
1351 1340

log4:

1351 1340
1351 2084
1350 1506
1352 1649
1351 1696
1351 2084
1352 1649
1351 1696
1351 1792
1351 2084
1351 1792
1351 2084
1351 1792
1350 1718
1351 1792
1350 1938
1350 2086
1351 1792
1350 1938
1351 1792
1351 2084
1351 1792
1351 2084
1350 1650
1351 2084
1350 1650

以上这些轨迹点都是从input event得到的，

首先是dump出input event，

# cat /dev/touchscreen > file

然后是用自己写的程序转化成坐标点。

# event_analyzer file

代码

event_analyzer.c

#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <linux/input.h>

//typedef __signed__ short __s16;
//typedef unsigned short __u16;
//
//typedef __signed__ int __s32;
//typedef unsigned int __u32;
//
//typedef long        __kernel_time_t;
//typedef long        __kernel_suseconds_t;
//
//struct timeval {
//    __kernel_time_t        tv_sec;        /* seconds */
//    __kernel_suseconds_t    tv_usec;    /* microseconds */
//};
//
//struct input_event {
//    struct timeval time;
//    __u16 type;
//    __u16 code;
//    __s32 value;
//};

char updown[2][10]={"up","down"};
char keyname[5][10]={"left","middle","right","finger","touch"};

int main( int argc, char **argv )
{
    int i,fd,fd_out,readin;
    FILE *stream;
    int x,y,unknown;
    char name[256],name_out[256];
    int key[5]={};
    struct input_event buf;
    bzero(&buf,sizeof(buf));
    for (i=1 ; i<argc ; i++) {
        strcpy(name,argv[i]);
        strcpy(name_out,name);
        strcat(name_out,"_out");
        //puts(name_out);
        if((fd = open(name,O_RDONLY)) == -1) {
            perror(name);
            continue;
        }
        else {
            printf("------------------------------------------------------------\n%s:\n",name);
            x=0;
            y=0;
            unknown=0;
            bzero(&buf,sizeof(buf));
            bzero(&key,sizeof(key));

            stream = fopen( name_out , "w+");
            if (stream == NULL) {
                perror(name_out);
//                continue;
            }

            while((readin = read(fd,&buf,sizeof(buf))) == sizeof(buf)) {
                //printf("%u-%u-%hu-%hu-%d\n",buf.time.tv_sec,buf.time.tv_usec,buf.type,buf.code,buf.value);
                if (buf.type == EV_ABS) {
                    if (buf.code == ABS_X) {
                    x = buf.value ;
                    } else if (buf.code == ABS_Y) {
                    y = buf.value ;
                    } else {
                        unknown |= 1;
                    }
                } else if (buf.type == EV_REL) {
                        unknown |= 2;
                } else if (buf.type == EV_KEY) {
                    switch (buf.code) {
                    case BTN_LEFT: key[0] |= 2 | buf.value; break;
                    case BTN_MIDDLE: key[1] |= 2 | buf.value; break;
                    case BTN_RIGHT: key[2] |= 2 | buf.value; break;
                    case BTN_TOOL_FINGER: key[3] |= 2 | buf.value; break;
                    case BTN_TOUCH: key[4] |= 2 | buf.value; break;
                    default: unknown |= 4; break;
                    }
                } else if (buf.type == EV_SYN && buf.code == SYN_REPORT) {
//                    if ( !x || !y ) {
//                          continue;
//                    }
                    char tmp[256]={};
                    char tmp2[256]={};
                    snprintf(tmp,256,"%d\t%d\t",x,y);
                    int i;
                    for (i=0 ; i<5 ; i++) {
                        if ( key[i] & 0x02 ) {
                              snprintf(tmp2,256,"%s <%s %s>",tmp,keyname[i],updown[key[i] & 0x01]);
                              strcpy(tmp,tmp2);
                        }
                    }
//                    if ( unknown )
//                          snprintf(tmp,256,"%s ",tmp,unknown);
                    printf("%s\n",tmp);
                    fprintf(stream,"%s\n",tmp);
//                    x=0;
//                    y=0;
                    unknown=0;
                    bzero(&buf,sizeof(buf));
                    bzero(&key,sizeof(key));
                } else {
                    unknown |= 8;
                }
            }
            if (readin > 0) {
                fprintf(stdout,"readin = %d\n",readin);
            }
        }
        close(fd);
        fclose(stream);
    }

    return 0;
}