Sorry. I was confused because it is using a 16-bit color space. You are right that each pixel is allocated three bytes.
// Expand 16-bit input color (Adafruit_GFX colorspace) to 24-bit (NeoPixel)
// (w/gamma adjustment)
static uint32_t expandColor(uint16_t color) {
return ((uint32_t)pgm_read_byte(&gamma5[color >> 11]) << 16) |
((uint32_t)pgm_read_byte(&gamma6[(color >> 5) & 0x3F]) << 8) |
pgm_read_byte(&gamma5[color & 0x1F]);
}
uint16_t Adafruit_NeoMatrix::Color(uint8_t r, uint8_t g, uint8_t b) {
return ((uint16_t)(r & 0xF8) << 8) | ((uint16_t)(g & 0xFC) << 3) | (b >> 3);
}