Hello everybody!
Today I placed s light installation at an festival and noticed that one led string in one object was mounted the wrong way! Is there a way to reverse one led string at the start of the program so we don’t havre to alter the code? This is what I use:
FastLED.addLeds<APA102, 12, 14, BGR>(leds, NUM_LEDS).setCorrection(CORRECTION);
FastLED.addLeds<APA102, 15, 13, BGR>(leds, NUM_LEDS).setCorrection(CORRECTION);
Thanks in advance 
Unfortunately - no, there isn’t : / You have to have two leds arrays, one which is a mirror image of the other (e.g.
FastLED.addLeds<APA102, 12, 14, BGR>(leds, NUM_LEDS).setCorrection(CORRECTION);
FastLED.addLeds<APA102, 15, 13, BGR>(leds_reversed, NUM_LEDS).setCorrection(CORRECTION);
and then before you call FastLED.show() do (to fill in the reverse led array:
for(i=0; i < NUM_LEDS; i++) { leds_reversed[(NUM_LEDS-1)-i] = leds[i]; }
FastLED.show();