ts_read, ts_read_raw, ts_read_mt, ts_read_raw_mt - read tslib touch samples
Contents
Description
ts_read() reads nr input samples with tslib's filters applied. structts_sample is define as follows:
struct ts_sample {
int x;
int y;
unsigned int pressure;
struct timeval tv;
};
ts_read_mt() reads nr * slots input samples with tslib's filters applied. structts_sample_mt is defined
as follows:
struct ts_sample_mt {
/* most recent ABS_MT_* event codes.
* see linux/input.h for descriptions */
int x;
int y;
unsigned int pressure;
int slot;
int tracking_id;
int tool_type;
int tool_x;
int tool_y;
unsigned int touch_major;
unsigned int width_major;
unsigned int touch_minor;
unsigned int width_minor;
int orientation;
int distance;
int blob_id;
struct timeval tv;
/* BTN_TOUCH state */
short pen_down;
/* the TSLIB_MT_VALID bit is set in valid if this sample
* contains new data;
* valid is set to 0 otherwise */
short valid;
};
The user has to provide the amount of memory described in nr and slots to hold them.
ts_read_raw() and ts_read_raw_mt() do the same thing without tslib's filters applied.
Example
The following program continuously reads tslib multitouch input samples and prints slot and position
values to stdout as the touch screen is touched.
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <tslib.h>
#define READ_SAMPLES 1
#define MAX_SLOTS 5
int main(int argc, char **argv)
{
struct tsdev *ts;
struct ts_sample_mt **samp_mt = NULL;
int i, j;
int ret;
ts = ts_setup(NULL, 0);
if (!ts)
return -1;
samp_mt = malloc(READ_SAMPLES * sizeof(struct ts_sample_mt **));
if (!samp_mt)
return -1;
for (i = 0; i < READ_SAMPLES; i++) {
samp_mt[i] = calloc(MAX_SLOTS, sizeof(struct ts_sample_mt));
if (!samp_mt[i])
return -1;
}
while(1) {
ret = ts_read_mt(ts, samp_mt, MAX_SLOTS, READ_SAMPLES);
for (i = 0; i < ret; i++) {
printf("sample nr %d0, i);
for (j = 0; i < MAX_SLOTS; j++) {
if (!(samp_mt[i][j].valid & TSLIB_MT_VALID))
continue;
printf("slot %d: X:%d Y: %d0,
samp_mt[i][j].slot,
samp_mt[i][j].x,
samp_mt[i][j].y);
}
}
}
}
Name
ts_read, ts_read_raw, ts_read_mt, ts_read_raw_mt - read tslib touch samples
Return Value
The number of actually read samples is returned. Especially when opened in non-blocking mode, see
ts_setup() , that can be less than requested in the call. On failure, a negative error number is
returned.
See Also
ts_setup(3), ts_config(3), ts_open(3), ts_close(3), ts.conf(5) TS_READ(3)
Synopsis
#include<tslib.h>intts_read(structtsdev*dev,structts_sample*samp,intnr);intts_read_raw(structtsdev*dev,structts_sample*samp,intnr);intts_read_mt(structtsdev*dev,structts_sample_mt**samp,intslots,intnr);intts_read_raw_mt(structtsdev*dev,structts_sample_mt**samp,intslots,intnr);
