RGB565 have inverted channels for display

[dimitre]

I've noticed today that display uses wrong colors for RGB565

this is Blue 0b111111 << 10 this is Red 0b11111 << 5 and this is Green 0b11111

Bit	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
RGB565	r	r	r	r	r	g	g	g	g	g	g	b	b	b	b	b
Maixduino	b	b	b	b	b	b	r	r	r	r	r	g	g	g	g	g

So channels are inverted and bit depth also, the correct order would be RGB with Green with 6 bits instead of blue. Thank you

[dimitre]

it seems to work OK on display if bits are swapped like this

uint16_t rgbto565(uint8_t r, uint8_t g, uint8_t b) {
    return ((b >> 3) << 11) | ((r>>3) << 6) | g >> 2;
}

instead of normal RGB565 bit order:

uint16_t rgbto5651(uint8_t r, uint8_t g, uint8_t b) {
    return ((b>>3) << 11) | ((g>>2) << 5) | r >> 3;
}

[Neutree]

we only set invert rgb to bgr on maixcube maixamigo, but maixduino seems no need to invert anything.(it's benn long time last I play k210, so I can not remember it clearly now, you can find code in MaixPy-v1 repo)

https://github.com/sipeed/MaixPy-v1/blob/a95e2eee386a34c99fd990394fcbba19f149e149/components/drivers/lcd/src/lcd_rgb.c#L510

https://github.com/sipeed/MaixPy-v1/blob/a95e2eee386a34c99fd990394fcbba19f149e149/components/drivers/lcd/src/lcd_mcu.c#L242

[dimitre]

Now I understand better, if I draw to the LCD, RGB565 is correct but if I draw to a canvas GFXCanvas16, then COLOR_RED draws blue.