Displaying Icons on 3.5in TFT Touch Screen (ILI9481)

Other Hardware Displays
1

Hi everyone,
This is my first post on an Arduino forum, so if my post isn't at the right spot just let me know :). I'm currently working on a automatic bonsai tree care program. I'm now it the stage of building and programming the TFT interface and as mentioned in the title I'm using a 3.5in TFT touchscreen with a Arduino Mega 2650. I have problem displaying icons on the screen. I tried to find online for hours and all i could find either wasn't what i wanted to do or didn't work... This forum is my last resort. I need your help hahaha! I've attached my sketch folder with the program I have so far and the icon I'm trying to display. If anybody would be so kind to help me understand why it isn't working and what I need to do to make it work, it would be awesome!

Thank you very much!
Arcadia117

Auto_Bonsai_Care__v1.0.zip (10.1 KB)

2

You have generated a C array of (uint16_t) pixels in your Icons directory.
But then you changed the type to uint8_t in the icons.c tab.

There are several ways to show a colour bitmap e.g.

...
extern const uint16_t SoilMoisture48[];  //pixel array in PROGMEM i.e uint16_t
...
     tft.drawRGBBitmap(260, 120, SoilMoisture48, 48, 48);

or

...
extern const uint16_t SoilMoisture48[];
...
    tft.setAddrWindow(260, 120, 260+48-1, 120+48-1); //this takes start, end arguments
    //pushColors() understands uint8_t arrays or uint16_t arrays in SRAM
    //pushColors() just expects a stream of bytes from PROGMEM.  It defaults to little-endian 
    tft.pushColors((const uint8_t*)SoilMoisture48,48*48,1);

I would advise using the GFX method. It may be SLOW but it is straightforward.

pushColors() is much faster. It can display images that are stored in big-endian or little-endian.

In practice, if your application has lots of icons you would write a helper function that does any horrible casting in one place.
If you only have one icon, just use the drawRGBBitmap() method.

void displayIcon(int x, int y, const uint16_t bitmap[], int w, int h)
{
#if 0
    tft.drawRGBBitmap(x, y, bitmap, w, h);  //GFX method
#else
    tft.setAddrWindow(x, y, x + w - 1, y + h - 1); //hardware method
    tft.pushColors((const uint8_t*)bitmap,w * h,true);
#endif
}
    ...
    // Display Icons
    displayIcon(260, 120, SoilMoisture48, 48, 48);
    ...

David.

3

Wow thank you very much !!! it finally worked !!

1 Like
4

Which did you choose?

GFX method or hardware method?

Thanks for pointing out the ambiguity.
If and when I issue a new Release of the library, I will clarify the example.

David.

5

Hi David,
I used the hardware method since i have about 11 icons to display at different moment on the screen depending on temperature, water tank level, etc..! so this method worked best for me ! I have another question thought that might be in the same category of this post. I'm currently working on updating the value of different sensor and i want to only display them when I'm on the home screen (currentPage = 1). When I start the program it only gets the first reading and when it goes for the second reading, my home screen disappear and the TFT display goes white. If i look on the serial monitor thought, I can see my programm working and to what it supposed to do (i.e. activate step motor, turn on/off relays, etc..). Could you help me with that ? I've attached the program and a picture of the wiring if you want to try it!
Thank you so much for your help!
Arcadia117

Auto_Bonsai_Care__v1.0_2020-03-06.zip (277 KB)

6

I strongly recommend that you study the "button_simple" example.
Life is easier with Adafruit_GFX_Button
And Touch is easier with copy-paste of "const int" statements instead of #defines.

Your white screen is due to:

  digitalWrite(13, HIGH);
  TSPoint p = ts.getPoint();   // Read touchscreen
  digitalWrite(13, LOW);
  
  pinMode(XM, OUTPUT);
  pinMode(YM, OUTPUT);

The Analog Touch pins are XM, YP. You will crash if you don't restore after a ts.getPoint() call.

const char softwareVersion[4] = "v1.0";

Your array is too small to hold the NUL. (hence the garbage print)

David.

7

Thanks for the fast reply!! i really appreciate it ! so to my understanding the only problem was that YM instead of YP in the loop ? god i would have looked a long time to find that problem if it wasn't for you. On the subject of the touch button, is the Adafruit_GFX_button is include in the Adafruit_GFX library? because i'm looking for the "button_simple" example but i can't find it

Thanks a lot !
Arcadia117

8

Button_simple.ino is a MCUFRIEND_kbv example.