I have the Arduino MEGA and an adafruit touch screen 2.8 inches.

My goal is to draw a pixel given a specific RGB

I am using the ILI9341, GFX, and TFT.h libraries to draw and control the touch screen. I noticed the drawPixel function given, in which it takes in three parameters and draws the pixel:


But, I am trying to draw a pixel with specific a RGB. So instead, the function would ideally need 5 parameters instead of 3, x, y, and then R, G, and B:


I tried putting in a number as the third parameter and not ILI9341_COLOR, and the screen just prints blue:


Is there a function that allows me to draw RGB pixels specifically? Thanks for any help!

1 Answer 1


As noted in the second paragraph on Adafruit's Graphics Library webpage,

First thing to note is that color is 16-bit, and that includes Red, Green and Blue in a 16-bit variable. The way the color is packed in is the top 5 bits are red, the middle 6 bits are green and the bottom 5 bits are blue.

If you want to specify 8-bit color components, you could write an intermediary routine to translate from that form to the 565 form. For example:

#define rgbDrawPixel(x,y,r,g,b) drawPixel(x,y,(((r)&0b11111000)<<8)|(((g)&0b11111100)<<3)|(((b)&0b11111000)>>3))

Note, this assumes the TFT library you're using has the same specs as Adafruit's. That might or might not be; I don't know how to account for a 255 color number showing up as blue rather than white.

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