NAME

ts_read, ts_read_raw, ts_read_mt, ts_read_raw_mt - read tslib touch samples

SYNOPSIS

#include <tslib.h>

int ts_read(struct tsdev *dev, struct ts_sample *samp, int nr);

int ts_read_raw(struct tsdev *dev, struct ts_sample *samp, int nr);

int ts_read_mt(struct tsdev *dev, struct ts_sample_mt **samp, int slots, int nr);

int ts_read_raw_mt(struct tsdev *dev, struct ts_sample_mt **samp, int slots, int nr);

DESCRIPTION

ts_read() reads nr input samples with tslib's filters applied. struct ts_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. struct ts_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.

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.

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);


                        }


                }


        }
}

SEE ALSO

ts_setup(3), ts_config(3), ts_open(3), ts_close(3), ts.conf(5)