Bug? TFT_eFEX ignores screen offset set on TFT_eSPI

[zaraken]

I have roughly the following setup

I have an ESP32 TTGO with ST7789_DRIVER
CGRAM_OFFSET is defined
my code is:

TFT_eSPI tft = TFT_eSPI();
TFT_eFEX tft_x = TFT_eFEX(&tft);

tft.begin();
// tft.setOrientation(1); // setting the orientation on tft object

tft_x.drawJpg(img_buff, buff_size, 0, 0); // ESP32 optimized 

The problem is (was) that the TFT_eFEX::drawJpg was not applying the necessary offset to the picture and as a result the picture was cropped/not centered. And in fact it looked like it was ignoring configurations that are applied to the TFT_eSPI object such as the setOrientation.

I traced it to this line

TFT_eFEX/TFT_eFEX.cpp

Line 1488 in 2b12725

jpeg.tft = this;

where jpeg.tft is assigned the extended TFT_eFEX object (this same as tft_x from my code above) which is itself also a TFT_eSPI object but not the original one on which the configurations are applied. The original object (tft from my code) is stored in tft_x during TFT_eFEX instantiation here

TFT_eFEX/TFT_eFEX.cpp

Line 18 in 2b12725

_tft = tft; // Pointer to tft class so we can call member functions

So I changed the line 1488 to
jpeg.tft = _tft;
and that fixed this particular problem that I had. But I'm not sure if this would create other problems. Is this a bug that I found, or is this just a workaround for my lack of understanding on how to use the library properly?

Alternatively could I instead apply configurations on the extended object directly like so

TFT_eSPI tft = TFT_eSPI();
TFT_eFEX tft_x = TFT_eFEX(&tft);

tft_x.begin();
// tft_x.setOrientation(1); // setting the orientation on tft object

tft_x.drawJpg(img_buff, buff_size, 0, 0); // ESP32 optimized 

And if that is possible do I need to instantiate TFT_eSPI at all ? Can't I just use TFT_eFEX?

[zaraken]

One clarification, my code was based on the library's examples https://github.com/Bodmer/TFT_eFEX/blob/master/examples/Jpeg_ESP32/Jpeg_ESP32.ino

[jsmestad]

@zaraken thanks for the fix. I was having the same issue 👍