ESP32 + HX8357d + Squareline Studio + Touchscreen

Going back to Squareline Studio (SLS), I incorporated the TouchScreen library and code from this previous experiment. I added a, very very simple, second screen:

Then added an Event to each screen with the “Released” trigger:

Here’s the complete code, interesting bits are bolded:

//Arduino-TFT_eSPI board-template main routine. There's a TFT_eSPI create+flush driver already in LVGL-9.1 but we create our own here for more control (like e.g. 16-bit color swap).

#include <lvgl.h>
#include <TFT_eSPI.h>
#include <ui.h>
#include <TouchScreen.h>

/*Don't forget to set Sketchbook location in File/Preferences to the path of your UI project (the parent foder of this INO file)*/

/*Change to your screen resolution*/
static const uint16_t screenWidth  = 480;
static const uint16_t screenHeight = 320;

enum { SCREENBUFFER_SIZE_PIXELS = screenWidth * screenHeight / 10 };
static lv_color_t buf [SCREENBUFFER_SIZE_PIXELS];

TFT_eSPI tft = TFT_eSPI( screenWidth, screenHeight ); /* TFT instance */

#define YP A19 // must be an analog pin, use "An" notation!
#define XM A15 // must be an analog pin, use "An" notation!
#define YM 14  // can be a digital pin
#define XP 27  // can be a digital pin

// Touchscreen coordinates: (x, y) and pressure (z)
// For better pressure precision, we need to know the resistance
// between X+ and X- Use any multimeter to read it
// For the one we're using, its 281 ohms across the X plate
TouchScreen ts = TouchScreen(XP, YP, XM, YM, 281);

int x, y, z;

#if LV_USE_LOG != 0
/* Serial debugging */
void my_print(const char * buf)
{
    Serial.printf(buf);
    Serial.flush();
}
#endif

/* Display flushing */
void my_disp_flush (lv_display_t *disp, const lv_area_t *area, uint8_t *pixelmap)
{
    uint32_t w = ( area->x2 - area->x1 + 1 );
    uint32_t h = ( area->y2 - area->y1 + 1 );

    if (LV_COLOR_16_SWAP) {
        size_t len = lv_area_get_size( area );
        lv_draw_sw_rgb565_swap( pixelmap, len );
    }

    tft.startWrite();
    tft.setAddrWindow( area->x1, area->y1, w, h );
    tft.pushColors( (uint16_t*) pixelmap, w * h, true );
    tft.endWrite();

    lv_disp_flush_ready( disp );
}

/*Read the touchpad*/
void my_touchpad_read (lv_indev_t * indev_driver, lv_indev_data_t * data)
{
    uint16_t touchX = 0, touchY = 0, touchZ = 0;

    // Get Touchscreen points
    TSPoint p = ts.getPoint();

    // Checks if Touchscreen was touched, and prints X, Y and Pressure (Z)
    if ( p.z > 15 ) {
    
      // Calibrate Touchscreen points with map function to the correct width and height
      touchX = map(p.y, 970, 205, 1, screenWidth);
      touchY = map(p.x, 248, 875, 1, screenHeight);
      touchZ = p.z;

      data->state = LV_INDEV_STATE_PR;

      // Set the coordinates
      data->point.x = touchX;
      data->point.y = touchY;

      Serial.print( "Data x " );
      Serial.println( touchX );

      Serial.print( "Data y " );
      Serial.println( touchY );

      Serial.print( "Data z " );
      Serial.println( touchZ );
    }
    else
    {
        data->state = LV_INDEV_STATE_REL;
    }
}

/*Set tick routine needed for LVGL internal timings*/
static uint32_t my_tick_get_cb (void) { return millis(); }

void setup ()
{
    Serial.begin( 115200 ); /* prepare for possible serial debug */

    // Set ADC resolution required for TouchScreen library
    analogReadResolution(10);

    String LVGL_Arduino = "Hello Arduino! ";
    LVGL_Arduino += String('V') + lv_version_major() + "." + lv_version_minor() + "." + lv_version_patch();

    Serial.println( LVGL_Arduino );
    Serial.println( "I am LVGL_Arduino" );

    lv_init();

#if LV_USE_LOG != 0
    lv_log_register_print_cb( my_print ); /* register print function for debugging */
#endif

    tft.begin();          /* TFT init */
    tft.setRotation( 3 ); /* Landscape orientation, flipped */

    static lv_disp_t* disp;
    disp = lv_display_create( screenWidth, screenHeight );
    lv_display_set_buffers( disp, buf, NULL, SCREENBUFFER_SIZE_PIXELS * sizeof(lv_color_t), LV_DISPLAY_RENDER_MODE_PARTIAL );
    lv_display_set_flush_cb( disp, my_disp_flush );

    static lv_indev_t* indev;
    indev = lv_indev_create();
    lv_indev_set_type( indev, LV_INDEV_TYPE_POINTER );
    lv_indev_set_read_cb( indev, my_touchpad_read );

    lv_tick_set_cb( my_tick_get_cb );

    ui_init();

    Serial.println( "Setup done" );
}

void loop ()
{
    lv_timer_handler(); /* let the GUI do its work */
    delay(5);
}