offset-gcode.c

/*  Offset gcode tool (with speed change)
 *  -------------------------------------
 *
 *  Compile: 'cc -o offset-gcode offset-gcode.c'
 *
 *  Use: 'offset-gcode -x 12.0 -y 12.0 -f 1.2 file.gcode > newfile.gcode'
 *
 */

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

static const char *program_name = "offset-gcode";

void print_usage() {
  printf("Usage: %s [-x nn.nn] [-y nn.nn] [-f nn.nn] <filename>\n", program_name);
}

enum {
  G1_X = 0x01,
  G1_Y = 0x02,
  G1_Z = 0x04,
  G1_E = 0x08,
  G1_F = 0x10
};

struct s_gmove {
  int gcode;
  int contains;
  double x;
  double y;
  double z;
  double e;
  int f;
};
typedef struct s_gmove gmove;

void decode_gmove(gmove *data, char *line);
void output_gmove(gmove *data);

double offset_x = 0.0;
double offset_y = 0.0;
double factor_f = 1.0;

int main(int argc, char *argv[]) {
  int opt;
      
  while ((opt = getopt(argc, argv, "hx:y:f:")) != -1) { 
    switch(opt) { 
      case 'x': 
        offset_x = atof(optarg);
        break; 

      case 'y': 
        offset_y = atof(optarg);
        break; 

      case 'f': 
        factor_f = atof(optarg);
        break; 

      case 'h':
        print_usage();        
        return 1;
    } 
  } 

  if (optind >= argc) {
    print_usage();
    return 2;
  }

  FILE *fp = fopen(argv[optind], "rt");
  if (fp == NULL) {
    print_usage();
    printf("Could not open: '%s'\n", argv[optind]);
    return 2;
  }

  int active = 1;
  char buffer[256];

  while (fgets(buffer, 256, fp) == buffer) {
    if (active &&
        (!strncmp("G0 ", buffer, 3) ||
         !strncmp("G1 ", buffer, 3))) {
      gmove data;
      decode_gmove(&data, buffer);
      data.x += offset_x;
      data.y += offset_y;
      if (data.contains & (G1_X | G1_Y | G1_Z)) {
        data.f *= factor_f;
      }
      output_gmove(&data);
    } else if (!strncmp("G90", buffer, 3)) {
      active = 1;
      printf("%s", buffer);
    } else if (!strncmp("G91", buffer, 3)) {
      active = 0;
      printf("%s", buffer);
    } else {
      printf("%s", buffer);
    }
  }

  fclose(fp);
  return 0;
}

void decode_gmove(gmove *data, char *line) {
  data->contains = 0;
  if (line[0] == 'G' &&
      (line[1] == '0' || line[1] == '1')) {
    char *x = strstr(line, "X");
    char *y = strstr(line, "Y");
    char *z = strstr(line, "Z");
    char *e = strstr(line, "E");
    char *f = strstr(line, "F");
    data->gcode = line[1] - '0';
    if (x) {
      data->contains |= G1_X;
      sscanf(x+1, "%lg", &data->x);
    }
    if (y) {
      data->contains |= G1_Y;
      sscanf(y+1, "%lg", &data->y);
    }
    if (z) {
      data->contains |= G1_Z;
      sscanf(z+1, "%lg", &data->z);
    }
    if (e) {
      data->contains |= G1_E;
      sscanf(e+1, "%lg", &data->e);
    }
    if (f) {
      data->contains |= G1_F;
      sscanf(f+1, "%d", &data->f);
    }
  }
}

void output_double(double value) {
  char buffer[32];
  sprintf(buffer, "%lg", value);
}

void output_gmove(gmove *data) {
  printf("G%d", data->gcode);
  if (data->contains & G1_X) {
    printf(" X%lg", data->x);
  }
  if (data->contains & G1_Y) {
    printf(" Y%lg", data->y);
  }
  if (data->contains & G1_Z) {
    printf(" Z%lg", data->z);
  }
  if (data->contains & G1_E) {
    printf(" E%lg", data->e);
  }
  if (data->contains & G1_F) {
    printf(" F%d", data->f);
  }
  printf("\n");
}