tftbmp.py

from st7735 import TFT, TFTColor
from machine import SPI, Pin

spi = SPI(
    1, baudrate=20000000, polarity=0, phase=0, sck=Pin(10), mosi=Pin(11), miso=None
)
tft = TFT(spi, 16, 17, 18)
tft.initr()
tft.rgb(True)
tft.fill(TFT.BLACK)

# Note BMP file needs to be in 24 bit format
f = open("tux.bmp", "rb")
if f.read(2) == b"BM":  # header
    dummy = f.read(8)  # file size(4), creator bytes(4)
    offset = int.from_bytes(f.read(4), "little")
    hdrsize = int.from_bytes(f.read(4), "little")
    width = int.from_bytes(f.read(4), "little")
    height = int.from_bytes(f.read(4), "little")
    if int.from_bytes(f.read(2), "little") == 1:  # planes must be 1
        depth = int.from_bytes(f.read(2), "little")
        if (
            depth == 24 and int.from_bytes(f.read(4), "little") == 0
        ):  # compress method == uncompressed
            print("Image size:", width, "x", height)
            rowsize = (width * 3 + 3) & ~3
            if height < 0:
                height = -height
                flip = False
            else:
                flip = True
            w, h = width, height
            if w > 128:
                w = 128
            if h > 160:
                h = 160
            tft._setwindowloc((0, 0), (w - 1, h - 1))
            for row in range(h):
                if flip:
                    pos = offset + (height - 1 - row) * rowsize
                else:
                    pos = offset + row * rowsize
                if f.tell() != pos:
                    dummy = f.seek(pos)
                for col in range(w):
                    bgr = f.read(3)
                    tft._pushcolor(TFTColor(bgr[2], bgr[1], bgr[0]))
spi.deinit()