png_test.py

import png
from board_config import display_drv
from displaybuf import DisplayBuffer, alloc_buffer
from collections import namedtuple
from time import sleep
import os


png_image = namedtuple("png_image", ["width", "height", "pixels", "metadata"])


# iterator to recursively find all .png files in a directory
def png_files(directory):
    for root, _, files in os.walk(directory):
        for file in files:
            if file.endswith(".png"):
                yield os.path.join(root, file)


png_path = "/home/brad/gh2/material-design-icons/png/"
fg_color = 0xFFFF
bg_color = 0x001F

canvas = DisplayBuffer(display_drv)
canvas.fill(bg_color)
canvas.show()

while True:
    for file_name in png_files(png_path):
        p = png_image(*png.Reader(filename=file_name).read())
        if not p.metadata["greyscale"] or p.metadata["bitdepth"] != 8:
            print(f"Only 8-bit PNGs are supported {file_name}")
            continue
        pos_x, pos_y = (canvas.width - p.width) // 2, (canvas.height - p.height) // 2
        offset = 1 if p.metadata["alpha"] else 0
        planes = p.metadata["planes"]
        buf = alloc_buffer(p.width * p.height * 2)
        for y, row in enumerate(p.pixels):
            for x in range(p.width):
                if row[x * planes + offset] > 127:
                    buf[(y * p.width + x) * 2 : (y * p.width + x) * 2 + 2] = fg_color.to_bytes(
                        2, "little"
                    )
                else:
                    buf[(y * p.width + x) * 2 : (y * p.width + x) * 2 + 2] = bg_color.to_bytes(
                        2, "little"
                    )
        canvas.blit_rect(buf, pos_x, pos_y, p.width, p.height)
        lines = os.path.relpath(file_name, png_path).rpartition("/")
        canvas.text16(lines[0] + "/", 0, 0, 0xFFFF)
        canvas.text16("    " + lines[2], 0, 16, 0xFFFF)
        canvas.show()
        sleep(1)
        canvas.fill_rect(pos_x, pos_y, p.width, p.height, bg_color)
        canvas.fill_rect(0, 0, canvas.width, 32, bg_color)