V5 Controller printing utility

controller_print.cpp

// arrays to store the three lines of text
std::array<std::string, 3> lines = {};
// used to compare with previous text to see if an update to the controller is needed
std::array<std::string, 3> lastLines = {};

// to print text, all you need to do is write to the `lines` array
// lines[lineNum] = "text";

void controller_print(void*){
  // the code will fill the text with spaces or trim the end of the text, 
  // so that the length of the text is exactly 15 characters
  const int maxWidth = 15;

  while(true) {

    // make sure there is no starving, if main loop delay does not get called.
    // throughout all the code, if no delays get called (happens if text does not change),
    // then a delay will be called so the task can yield
    bool delayed = false; 

    // loop through each line, i = lineNum
    for(int i = 0; i < lines.size(); i++) {

      // check to see if the line needs to be reprinted (if it changed).
      // to find out if this optimization makes any difference, replace with `if(true)`,
      // then it will update each line every 52ms
      if(lines.at(i) != lastLines.at(i)) {

        // make a copy of the text
        std::string str = lines.at(i);
        // if the text is smaller than 15 characters
        if(str.size() < maxWidth) {
          // insert spaces at the end so the text is 15 characters long
          // hopefully this overwrites everything on the screen
          str.insert(str.end(), maxWidth - str.size(), ' ');
        } else {
          // if the text is larger than 15 characters,
          // trim the end of the text so it is 15 characters long.
          // that text won't be shown on the display anyways.
          str.erase(str.begin() + maxWidth, str.end());
        }

        // send the padded/sized text to the controller
        // `str.c_str()` is needed to convert the `std::string` into a `const char*`
        pros::c::controller_set_text(pros::E_CONTROLLER_MASTER, i, 0, str.c_str());
        // record the text for future comparison
        lastLines.at(i) = lines.at(i);
        // the important delay
        pros::delay(52);
        // lets the code know a delay occured, so another one is not neccecary
        delayed = true;
      }
    }

    // if the printing was skipped, make sure the loop has a delay
    if(!delayed) {
      pros::delay(52);
    }
  }
}