B4R Question TTGO32 display drawing?

sorex · Mar 31, 2021

Hello,

A while ago I bought a TTGO32(?) which is an esp32 variant with LCD and other thing default on the board.
As it required an USB-C cable (which I didn't have back then) to connect to it or to power it it went out of sight untill I bumped onto such cable today at work.

I can compile the basic program to it so that not the problem.

I didn't figure out yet how I can put text to the display.

I did some searching and found an Adafruit Gfx lib from Erel. I don't know if this will work with this board or not as it refuses to compile.

It always gives these errors in @Cableguy 's lcd example ...

In file included from C:\Users\xxx\DOWNLO~1\lcd-test\Objects\bin\sketch\rAdafruit_ST7735.h:3:0,
from C:\Users\xxx\DOWNLO~1\lcd-test\Objects\bin\sketch\B4RDefines.h:26,
from C:\Users\xxx\DOWNLO~1\lcd-test\Objects\src\src.ino:1:
Adafruit_ST7735.h:29:26: fatal error: Adafruit_GFX.h: No such file or directory

I installed the wrapped lib into the additional libs folder.
I also installed the lib in the arduino application but the error remains.

Any idea?

sorex · Mar 31, 2021

got a small step further...

when using the guidelines of @Peter Simpson in this link > https://www.b4x.com/android/forum/t...-in-oled-display-progress-bar-inline-c.81391/
(copy the lib files to %userprofile%\documents\arduino\libraries and untag the lib in B4R)
it compiles and runs altho nothing gets displayed.

my board might use different ports or something.

after some more net searching it appears that I need tft_espi so I'll do some more testing tomorrow.

RJB · Apr 1, 2021

Hi,
not sure if this is the same board as the Lilygo TTGO T-Display?
I got this working for text and graphics(565RGB and JPeg) following the information in:
https://sites.google.com/site/jmaathuis/arduino/lilygo-ttgo-t-display-esp32
and Bodmer on Github (TFT_eSPI.h / SPI.h)
Unfortunately my implementation is a bit piecemeal as I don't know how to 'wrap' the library.

example (cut and paste so may not work exactly as shown!:

B4X:

Sub JpgImage(FileName As String)
  
   Dim bb() As Byte = FileName
   RunNative("JPegImage", bb)
  
End Sub


#If C

#include <TFT_eSPI.h>
#include <SPI.h>
#include <JPEGDecoder.h>  // JPEG decoder library
#include <FS.h>

TFT_eSPI tft = TFT_eSPI(135, 240);
void JPegImage(B4R::Object* o) {

       B4R::Array* b = (B4R::Array*)B4R::Object::toPointer(o);
        char* c = (char*)b->data;
        File jpgFile = SPIFFS.open(c, FILE_READ);
        JpegDec.decodeFsFile(jpgFile);
        renderJPEG(0, 0);

}

//from: https://stackoverflow.com/questions/54182286/how-To-convert-jpeg-byte-stream-into-jpeg-image-And-display-On-1-8-inch-tft-disp
void renderJPEG(int xpos, int ypos) {

  // retrieve infomration about the image
  uint16_t *pImg;
  uint16_t mcu_w = JpegDec.MCUWidth;
  uint16_t mcu_h = JpegDec.MCUHeight;
  uint32_t max_x = JpegDec.width;
  uint32_t max_y = JpegDec.height;

  // Jpeg images are draw as a set of image block (tiles) called Minimum Coding Units (MCUs)
  // Typically these MCUs are 16x16 pixel blocks
  // Determine the width and height of the right and bottom edge image blocks
  uint32_t min_w = minimum(mcu_w, max_x % mcu_w);
  uint32_t min_h = minimum(mcu_h, max_y % mcu_h);

  // save the current image block size
  uint32_t win_w = mcu_w;
  uint32_t win_h = mcu_h;

  // save the coordinate of the right and bottom edges to assist image cropping
  // to the screen size
  max_x += xpos;
  max_y += ypos;

  // read each MCU block until there are no more
  while ( JpegDec.read()) {

    // save a pointer to the image block
    pImg = JpegDec.pImage;

    // calculate where the image block should be drawn on the screen
    int mcu_x = JpegDec.MCUx * mcu_w + xpos;
    int mcu_y = JpegDec.MCUy * mcu_h + ypos;

    // check if the image block size needs to be changed for the right and bottom edges
    if (mcu_x + mcu_w <= max_x) win_w = mcu_w;
    else win_w = min_w;
    if (mcu_y + mcu_h <= max_y) win_h = mcu_h;
    else win_h = min_h;

    // calculate how many pixels must be drawn
    uint32_t mcu_pixels = win_w * win_h;

    // draw image block if it will fit on the screen
    if ( ( mcu_x + win_w) <= tft.width() && ( mcu_y + win_h) <= tft.height()) {

    //  Write all MCU pixels to the TFT window


      for (int jj=mcu_y;jj<mcu_y + win_h;jj++)
    {
        for (int ii=mcu_x;ii<mcu_x + win_w ;ii++)
        {
            tft.drawPixel(ii,jj,*pImg++ );
             //Serial.print  ("Pixel    : "); Serial.print(ii); Serial.print("   "); Serial.print(jj); Serial.print("   "); Serial.println(*pImg++);
        }
     } 
 }

    // stop drawing blocks if the bottom of the screen has been reached
    // the abort function will close the file
    else if ( ( mcu_y + win_h) >= tft.height()) JpegDec.abort();
 }

}

#end if

sorex · Apr 1, 2021

indeed it is a TTGO T-Display.

and I managed to get it working aswell but as you wrote a wrapped lib would be usefull as the library has a lot of functions
( (fill)rect, (fill)circle, (fill)elipse, (fill)triangle, lines etc) but I don't know how to pass the parameters from B4R to the inline C routines.

this is the library that I've put in my %userprofile%\documents\arduino\libraries

~~https://github.com/Bodmer/TFT_eSPI~~

Edit: {
correction...

I used this but it seems to be the same or based on the Bodmer one but only has the parts needed for the TTGO T-Display and ports set correctly in the user_setup

GitHub - Xinyuan-LilyGO/TTGO-T-Display

Contribute to Xinyuan-LilyGO/TTGO-T-Display development by creating an account on GitHub.

github.com

}

here's the basic hello, world and the voltage example for those who are struggling to get this working aswell ...

B4X:

Sub Process_Globals
    Public Serial1 As Serial
End Sub

Private Sub AppStart
    Serial1.Initialize(115200)
    Log("AppStart")

    RunNative("tftInit", Null)

    Do While True
    Delay(1000)
    RunNative("tftShowVoltage", Null)
    Loop

End Sub


#if c

#include "TFT_eSPI.h"

//#define ADC_EN              14  //ADC_EN is the ADC detection enable port
#define ADC_PIN             34
//#define BUTTON_1            35
//#define BUTTON_2            0

TFT_eSPI tft = TFT_eSPI(135, 240); // Invoke custom library

void tftInit(B4R::Object* unused)
{
//    pinMode(ADC_EN, OUTPUT);
//    digitalWrite(ADC_EN, HIGH);

    tft.init();
    tft.setRotation(1);
    tft.fillScreen(TFT_BLACK);
    tft.setTextSize(2);
    tft.setTextColor(TFT_WHITE);
    tft.setTextDatum(MC_DATUM);    //centered string
    tft.drawString("Hello, world.", tft.width() / 2, tft.height() / 4);
}


void tftShowVoltage(B4R::Object* unused)
{
    int vref = 1100;
    uint16_t v = analogRead(ADC_PIN);
    float battery_voltage = ((float)v / 4095.0) * 2.0 * 3.3 * (vref / 1000.0);
    String voltage = "Voltage :" + String(battery_voltage) + "V";

    tft.fillRect(155,135/2-8,62,16,TFT_BLACK);    // only erase the value portion of the bitmap
    tft.setTextColor(TFT_GREEN);
    tft.setCursor(50,60);
    tft.print(voltage);                            // this gives less flashing than .drawString

//     tft.fillRect(0,135/2-8,240,14,TFT_BLACK);
//   tft.setTextDatum(MC_DATUM);
//   tft.drawString(voltage,  tft.width() / 2, tft.height() / 2 );
}
#End If

RJB · Apr 1, 2021

FYI The Bodmer files are also easy to configure for other displays. I have it working with 240 x 240 and 480 x 240 displays using ESP32s to drive them

B4R Question TTGO32 display drawing?

sorex

Expert

sorex

Expert

RJB

Active Member

sorex

Expert

GitHub - Xinyuan-LilyGO/TTGO-T-Display

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RJB

Active Member