tft.setTextColor with variable

[schnello]

Hello.

I build an PV Monitor and my target was to send via MQTT the power value and value color

 DynamicJsonDocument doc(64);
  deserializeJson(doc, value);
  String color = doc["color"];
  String power = doc["value"];

tft.print(power); ==> Works fine.

but if i try to do the same with the color i get only an error:
tft.setTextColor(color);

Content of color is the string "TFT_GREEN"

C:\Users\schne\Documents\Arduino\PV_Monitor\pv_monitor\pv_monitor.ino: In function 'void callback(char*, byte*, unsigned int)':
C:\Users\schne\Documents\Arduino\PV_Monitor\pv_monitor\pv_monitor.ino:66:20: error: 'color' was not declared in this scope
   66 |   tft.setTextColor(color);
      |                    ^~~~~
C:\Users\schne\Documents\Arduino\PV_Monitor\pv_monitor\pv_monitor.ino:113:25: error: no matching function for call to 'TFT_eSPI::setTextColor(String&)'
  113 |   tft.setTextColor(color);
      |                         ^
In file included from C:\Users\schne\Documents\Arduino\PV_Monitor\pv_monitor\pv_monitor.ino:18:
c:\Users\schne\Documents\Arduino\libraries\TFT_eSPI/TFT_eSPI.h:645:12: note: candidate: 'void TFT_eSPI::setTextColor(uint16_t)'
  645 |   void     setTextColor(uint16_t color),                    // Set character (glyph) color only (background not over-written)
      |            ^~~~~~~~~~~~
c:\Users\schne\Documents\Arduino\libraries\TFT_eSPI/TFT_eSPI.h:645:34: note:   no known conversion for argument 1 from 'String' to 'uint16_t' {aka 'short unsigned int'}
  645 |   void     setTextColor(uint16_t color),                    // Set character (glyph) color only (background not over-written)
      |                         ~~~~~~~~~^~~~~
c:\Users\schne\Documents\Arduino\libraries\TFT_eSPI/TFT_eSPI.h:646:12: note: candidate: 'void TFT_eSPI::setTextColor(uint16_t, uint16_t, bool)'
  646 |            setTextColor(uint16_t fgcolor, uint16_t bgcolor, bool bgfill = false),  // Set character (glyph) foreground and background colour, optional background fill for smooth fonts
      |            ^~~~~~~~~~~~
c:\Users\schne\Documents\Arduino\libraries\TFT_eSPI/TFT_eSPI.h:646:12: note:   candidate expects 3 arguments, 1 provided

exit status 1

Compilation error: 'color' was not declared in this scope

Atm i avoid this issue with an if contruct:

if( color == "TFT_GREEN"){  
  tft.setTextColor(TFT_GREEN);
}
if( color == "TFT_RED"){  
  tft.setTextColor(TFT_RED);
}
if( color == "TFT_YELLOW"){  
  tft.setTextColor(TFT_YELLOW);
}

But it would be great to be able to send directly the color via MQTT
Can someone give me a tip here?

[Bodmer]

The tft.setTextColor() function expects a 16 bit colour value (uint16_t) so the sourve will have to provide an integer colour or you will need to use the code you suggested above. This is where the colour values are defined:
https://github.com/Bodmer/TFT_eSPI/blob/master/TFT_eSPI.h#L300-L327