LLEMU C API module

bool lcd_is_initialized(void)

#include <liblvgl/include/liblvgl/llemu.h>

Checks whether the emulated three-button LCD has already been initialized.

Example

if (pros::c::lcd_is_initialized()) {
  pros::c::lcd_print("LLEMU!");
}
else {
  printf("Error: LLEMU is not initialized\n");
}

bool lcd_initialize(void)

#include <liblvgl/include/liblvgl/llemu.h>

Creates an emulation of the three-button, UART-based VEX LCD on the display.

Example

#include "pros/llemu.h"

void initialize() {
  if (pros::c::lcd_initialize()) {
    pros::c::lcd_print("LLEMU!");   
  }
  else {
       printf("Error: LLEMU could not initailize\n");
  }
}

bool lcd_shutdown(void)

#include <liblvgl/include/liblvgl/llemu.h>

Turns off the Legacy LCD Emulator.

Calling this function will clear the entire display, and you will not be able to call any further LLEMU functions until another call to lcd_initialize.

This function uses the following values of errno when an error state is reached: ENXIO - The LCD has not been initialized. Call lcd_initialize() first.

Example

#include "pros/llemu.h"

void disabled() {
  pros::c::lcd_shutdown();
}

bool lcd_print(int16_t line, const char* fmt, ...)

#include <liblvgl/include/liblvgl/llemu.h>

Displays a formatted string on the emulated three-button LCD screen.

This function uses the following values of errno when an error state is reached: ENXIO - The LCD has not been initialized. Call lcd_initialize() first. EINVAL - The line number specified is not in the range [0-7]

Example

#include "pros/llemu.h"

void initialize() {
  pros::c::lcd_initialize();
  pros::c::lcd_print(0, "My formatted text: %d!", 2);
}

bool lcd_set_text(int16_t line, const char* text)

#include <liblvgl/include/liblvgl/llemu.h>

Displays a string on the emulated three-button LCD screen.

This function uses the following values of errno when an error state is reached: ENXIO - The LCD has not been initialized. Call lcd_initialize() first. EINVAL - The line number specified is not in the range [0-7]

Example

#include "pros/llemu.h"

void initialize() {
  pros::c::lcd_initialize();
  pros::c::lcd_set_text(0, "My custom LLEMU text!");
}

bool lcd_clear(void)

#include <liblvgl/include/liblvgl/llemu.h>

Clears the contents of the emulated three-button LCD screen.

This function uses the following values of errno when an error state is reached: ENXIO - The LCD has not been initialized. Call lcd_initialize() first. EINVAL - The line number specified is not in the range [0-7]

Example

#include "pros/llemu.h"

void initialize() {
  pros::c::lcd_initialize();
  pros::c::lcd_clear(); // Clear the LCD screen
}

bool lcd_clear_line(int16_t line)

#include <liblvgl/include/liblvgl/llemu.h>

Clears the contents of a line of the emulated three-button LCD screen.

This function uses the following values of errno when an error state is reached: ENXIO - The LCD has not been initialized. Call lcd_initialize() first. EINVAL - The line number specified is not in the range [0-7]

Example

#include "pros/llemu.h"

void initialize() {
  pros::c::lcd_initialize();
  pros::c::lcd_clear_line(0); // Clear line 0
}

bool lcd_register_btn0_cb(lcd_btn_cb_fn_t cb)

#include <liblvgl/include/liblvgl/llemu.h>

Registers a callback function for the leftmost button.

When the leftmost button on the emulated three-button LCD is pressed, the user-provided callback function will be invoked.

This function uses the following values of errno when an error state is reached: ENXIO - The LCD has not been initialized. Call lcd_initialize() first.

Example

#include "pros/llemu.h"

void left_callback() {
  static int i = 0;
  
  i++;
  pros::c::lcd_print(0, "Left button pressed %i times", i);
}

void initialize() {
  pros::c::lcd_initialize();
  pros::c::lcd_register_btn0_cb();
}

bool lcd_register_btn1_cb(lcd_btn_cb_fn_t cb)

#include <liblvgl/include/liblvgl/llemu.h>

Registers a callback function for the center button.

When the center button on the emulated three-button LCD is pressed, the user-provided callback function will be invoked.

This function uses the following values of errno when an error state is reached: ENXIO - The LCD has not been initialized. Call lcd_initialize() first.

Example

#include "pros/llemu.h"

void center_callback() {
  static int i = 0;
  
  i++;
  pros::c::lcd_print(0, "Center button pressed %i times", i);
}

void initialize() {
  pros::c::lcd_initialize();
  pros::c::lcd_register_btn1_cb();
}

bool lcd_register_btn2_cb(lcd_btn_cb_fn_t cb)

#include <liblvgl/include/liblvgl/llemu.h>

Registers a callback function for the rightmost button.

When the rightmost button on the emulated three-button LCD is pressed, the user-provided callback function will be invoked.

This function uses the following values of errno when an error state is reached: ENXIO - The LCD has not been initialized. Call lcd_initialize() first.

Example

#include "pros/llemu.h"

void right_callback() {
  static int i = 0;
  
  i++;
  pros::c::lcd_print(0, "Right button pressed %i times", i);
}

void initialize() {
  pros::c::lcd_initialize();
  pros::c::lcd_register_btn2_cb();
}

uint8_t lcd_read_buttons(void)

#include <liblvgl/include/liblvgl/llemu.h>

Gets the button status from the emulated three-button LCD.

The value returned is a 3-bit integer where 1 0 0 indicates the left button is pressed, 0 1 0 indicates the center button is pressed, and 0 0 1 indicates the right button is pressed. 0 is returned if no buttons are currently being pressed.

Note that this function is provided for legacy API compatibility purposes, with the caveat that the V5 touch screen does not actually support pressing multiple points on the screen at the same time.

void lcd_set_text_align(text_align_e_t alignment)

#include <liblvgl/include/liblvgl/llemu.h>

Changes the alignment of text on the LCD background.

Example

#include "pros/llemu.h"

void initialize() {
  pros::c::lcd_initialize();
  pros::c::lcd_set_alignment(pros::c::lcd_Text_Align::LEFT);
  pros::c::lcd_print(0, "Left Aligned Text");
  pros::c::lcd_set_alignment(pros::c::lcd_Text_Align::CENTER);
  pros::c::lcd_print(1, "Center Aligned Text");
  pros::c::lcd_set_alignment(pros::c::lcd_Text_Align::RIGHT);
  pros::c::lcd_print(2, "Right Aligned Text");
}

enum lcd_text_align_e

#include <liblvgl/include/liblvgl/llemu.h>

Represents how to align the text in the LCD.