TFT_eSPI must be included before Adafruit_GFX for Free Fonts to function

[allanyates]

I have been making use of both the Adafruit_LEDBackpack library, for 7 segment display functionality, as well as TFT_eSPI for a TFT LCD display. Everything was proceeding well, until I tried to use the Free Font capability of the TFT library. I would then get compile errors like:

Free_Fonts.h:82:15: error: 'FreeSans9pt7b' was not declared in this scope
#define FSS9 &FreeSans9pt7b
               ^~~~~~~~~~~~~
C:\Users\ayates\My Drive\AJY\Marine\Clock\font\font.ino:190:19: note: in expansion of macro 'FSS9'
   tft.setFreeFont(FSS9);

I could get past the compile errors by manually including the specific font files. For example, like:

#include <Fonts/FreeSerifBold9pt7b.h>

However, I would get garbage displayed on the LCD.

I finally tracked down the issue being the inclusion of the Adafruit_LEDBackpack library before the include of the TFT_eSPI library. Specifically, it is the inclusion of the Adafruit_GFX library before the TFT_eSPI library. Adafruit_GFX is included by Adafruit_LEDBackpack.

Once I reversed the order, the compile is clean, and the Free Fonts are displayed correctly.

Bad:

#include <Adafruit_GFX.h>
#include <TFT_eSPI.h>

Good:

#include <TFT_eSPI.h>
#include <Adafruit_GFX.h>

I don't know that this is a bug somewhere, on one side or the other, or just the way things work. But documenting it in case other folk encounter.

Allan.

[Bodmer]

The TFT_eSPI library is not intended to work in tandem with Adafruit_GFX as both incorporate the same Free Fonts files.

Putting TFT_eSPI first is important in this case so it loads the required files before the Adafruit library loads and claims sole access.

[tochinet]

Hi Bodmer, ChatGPT made me discover this post, intersting. I expected that tft_eSPI.h would not be "compatible" with a later call on adafruit. I really prefer your library to Lady Ada's, but I sometimes have trouble migrating sketches, both for font usage as for TFT_WIDTH/HEIGHT and other definitions. FYI, the LLM also pointed out (I didn't verify) that your library didn't provide the followng functions : drawFastVLine(), drawFastHLine(), drawRoundRect(), fillRoundRect()] weirdly referring to this discussion as source of information. No big deal for me anyway.

I tried this path, and loading both libraries works, but when I replace teh adafruit object by a tft_espi object, it looks like many functions are missing (such ass setfont). Would you be so kind as recommending the best "path" for the migration ?

[dizcza]

Hi @tochinet I'm facing the same issue: I'm migrating Adafruit_SharpMem, which is a subclass of Adafruit_GFX, to TFT_eSPI. Lots of functions seem to either have a different name or are not implemented.

Have you advanced further than just this comment?