67 lines
2 KiB
Python
67 lines
2 KiB
Python
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
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# SPDX-License-Identifier: MIT
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#!/usr/bin/python3
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# This example runs on SBC devices like Raspberry Pi.
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# It cannot run on microcontrollers.
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# Light-painting example for Adafruit DotStar RGB LED strip.
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# Loads image, displays column-at-a-time on LEDs at a reasonable
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# speed for long exposure photography.
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# See dotstar_simpletest.py for a much simpler example script.
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# See dotstar_image_pov.py for a faster persistence-of-vision example.
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import time
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import board
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from PIL import Image
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import adafruit_dotstar as dotstar
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NUMPIXELS = 30 # Number of LEDs in strip
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FILENAME = "hello.png" # Image file to load
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# First two arguments in strip declaration identify the clock and data pins
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# (here we're using the hardware SPI pins). Last argument identifies the
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# color order -- older DotStar strips use GBR instead of BRG.
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DOTS = dotstar.DotStar(
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board.SCK,
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board.MOSI,
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NUMPIXELS,
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brightness=0.25,
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auto_write=False,
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pixel_order=dotstar.BGR,
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)
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# Load image in RGB format and get dimensions:
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print("Loading...")
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IMG = Image.open(FILENAME).convert("RGB")
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PIXELS = IMG.load()
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WIDTH = IMG.size[0]
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HEIGHT = IMG.size[1]
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print("%dx%d pixels" % IMG.size)
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HEIGHT = min(HEIGHT, NUMPIXELS)
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# Calculate gamma correction table, makes mid-range colors look 'right':
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GAMMA = bytearray(256)
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for i in range(256):
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GAMMA[i] = int(pow(float(i) / 255.0, 2.7) * 255.0 + 0.5)
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print("Displaying...")
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while True: # Loop forever
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for x in range(WIDTH): # For each column of image...
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for y in range(HEIGHT): # For each pixel in column...
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value = PIXELS[x, y] # Read pixel in image
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DOTS[y] = ( # Set pixel #y in strip
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GAMMA[value[0]], # Gamma-corrected red
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GAMMA[value[1]], # Gamma-corrected green
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GAMMA[value[2]], # Gamma-corrected blue
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)
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DOTS.show() # Refresh LED strip
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time.sleep(0.01) # Pause 1/100 sec.
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DOTS.fill(0) # Clear strip and pause 1/4 sec.
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DOTS.show()
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time.sleep(0.25)
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