Examples: initial version of 'image_gallery.py'

examples/image_gallery.py

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+'''
+An image gallery demo to turn your Pimoroni Presto into a desktop photo frame!
+
+- Create a folder called 'gallery' on the root of your SD card and fill it with JPEGs.
+- The image will change automatically every 5 minutes
+- You can also tap the right side of the screen to skip next image and left side to go to the previous :)
+
+'''
+import os
+import time
+
+import jpegdec
+import machine
+import plasma
+import sdcard
+import uos
+from ft6236 import FT6236
+from picographics import DISPLAY_PRESTO, PicoGraphics
+from presto import Presto
+
+machine.freq(264000000)
+
+# The total number of LEDs to set, the Presto has 7
+NUM_LEDS = 7
+
+# Where our images are located on the SD card
+DIR = 'sd/gallery'
+
+# Seconds between changing the image on screen
+# This interval shows us a new image every 5 minutes
+INTERVAL = 60 * 5
+
+LEDS_LEFT = [4, 5, 6]
+LEDS_RIGHT = [0, 1, 2]
+
+# Setup for the Presto display
+portal = Presto()
+display = PicoGraphics(DISPLAY_PRESTO, buffer=memoryview(portal)[240 * 240 * 2:], layers=2)
+WIDTH, HEIGHT = display.get_bounds()
+
+BACKGROUND = display.create_pen(1, 1, 1)
+WHITE = display.create_pen(255, 255, 255)
+BLACK = display.create_pen(0, 0, 0)
+
+# We'll need this for the touch element of the screen
+touch = FT6236()
+
+# JPEG Dec
+j = jpegdec.JPEG(display)
+
+# Plasma setup
+bl = plasma.WS2812(7, 0, 0, 33)
+bl.start()
+
+# Stores the total number of images in the user gallery
+total_image_count = 0
+
+# Store our current location within the user gallery
+current_image = 1   # First image in our gallery
+
+
+# We might not have enough space to load the entire directory list into RAM
+# so we iterate though 'os.ilistdir' and store each file name in a .txt file for later
+def create_index(dir):
+
+    # check to see if contents.txt exists and skip the indexing if it does.
+    if not file_exists(dir + "/index.txt"):
+
+        f = open(dir + "/index.txt", "a")
+
+        for file in os.ilistdir(dir):
+            # We're only looking for jpeg images, we don't want to index any other file type
+            if ".jpg" in file[0] or ".jpeg" in file[0]:
+                f.write(str(file[0]) + "\n")
+
+        f.close()
+
+        print("'index.txt' generated successfully!")
+
+    else:
+        print("\nindex.txt already generated! \nIf you have changed the files in the current directory you will need to delete 'content.txt' and run the program again.\n\n")
+
+
+def count_files(dir):
+    c = 0
+    for file in os.ilistdir(dir):
+        c += 1
+    return c - 1
+
+
+# Delete the current index file if it exists
+# This will force it to recreate it on the next boot.
+def delete_index(dir):
+    print("Removing 'index.txt'")
+    os.remove(dir + "/index.txt")
+
+
+lfsr = 1
+tap = 0xdc29
+
+
+def return_point():
+    global lfsr
+
+    x = lfsr & 0x00ff
+    y = (lfsr & 0xff00) >> 8
+
+    lsb = lfsr & 1
+    lfsr >>= 1
+
+    if lsb:
+        lfsr ^= tap
+
+    if x - 1 < 240 and y < 240:
+        return x - 1, y
+
+    return -1, -1
+
+
+def fizzlefade():
+    display.set_pen(BLACK)
+    display.set_layer(1)
+
+    while True:
+
+        for i in range(2000):
+            x, y = return_point()
+            if x > -1 and y > -1:
+                display.pixel(x, y)
+            if lfsr == 1:
+                break
+
+        portal.update(display)
+        if lfsr == 1:
+            break
+
+
+def show_image(show_next=False, show_previous=False):
+    global current_image
+    global total_image_count
+
+    # Get the next image in the gallery
+    # If we're at the end of the gallery, loop back and start from 1.
+    if show_next:
+        if current_image < total_image_count:
+            current_image += 1
+        else:
+            current_image = 1
+    if show_previous:
+        if current_image > 1:
+            current_image -= 1
+        else:
+            current_image = total_image_count
+
+    # Open the index file and read lines until we're at the correct position
+    try:
+        f = open(DIR + "/index.txt", 'r')
+        for i in range(current_image - 1):
+            f.readline()
+        file = f.readline()
+        f.close()
+
+        j.open_file(f"{DIR}/{file}")
+
+        img_height, img_width = j.get_height(), j.get_width()
+
+        img_x = 0
+        img_y = 0
+
+        # if the image isn't exactly 240x240 then we'll try to centre the image
+        if img_width < WIDTH:
+            img_x = (WIDTH // 2) - (img_width // 2)
+
+        if img_height < HEIGHT:
+            img_y = (HEIGHT // 2) - (img_height // 2)
+
+        display.set_layer(0)
+        display.set_pen(BACKGROUND)
+        display.clear()
+        j.decode(img_x, img_y, jpegdec.JPEG_SCALE_FULL, dither=True)
+
+        fizzlefade()
+
+        # Now draw the current image to Layer 1
+        display.set_layer(1)
+        # Decode the JPEG
+        j.decode(img_x, img_y, jpegdec.JPEG_SCALE_FULL, dither=True)
+
+    except OSError:
+        display_error("Unable to find/read file.\n\nCheck that the 'gallery' folder in the root of your SD card contains JPEG images!")
+
+
+def clear():
+    display.set_pen(BACKGROUND)
+    display.set_layer(0)
+    display.clear()
+    display.set_layer(1)
+    display.clear()
+
+
+# Display an error msg on screen and keep it looping
+def display_error(text):
+    while 1:
+        display.set_pen(BACKGROUND)
+        display.clear()
+        display.set_pen(WHITE)
+        display.text(f"Error: {text}", 10, 10, WIDTH - 10, 1)
+        portal.update(display)
+        time.sleep(1)
+
+
+try:
+    # Setup for SD Card
+    sd_spi = machine.SPI(0, sck=machine.Pin(34, machine.Pin.OUT), mosi=machine.Pin(35, machine.Pin.OUT), miso=machine.Pin(36, machine.Pin.OUT))
+    sd = sdcard.SDCard(sd_spi, machine.Pin(39))
+
+    # Mount the SD to the directory 'sd'
+    uos.mount(sd, "/sd")
+except OSError:
+    display_error("Unable to mount SD card")
+
+
+# Function to check if a file is present on the filesystem
+def file_exists(filename):
+    try:
+        return (os.stat(filename)[0] & 0x4000) == 0
+    except OSError:
+        return False
+
+
+try:
+    # Delete the index to force it to recreate the file in the next step
+    delete_index(DIR)
+except OSError:
+    print("Unable to delete index")
+
+# Create the index
+# And count the images
+try:
+    create_index(DIR)
+    total_image_count = count_files(DIR)
+except OSError:
+    display_error("Unable to create index file. \nCheck that your file names do not contain non unicode characters.")
+
+
+# Store the last time the screen was updated
+last_updated = time.time()
+
+# Show the first image on the screen so it's not just noise :)
+# We're not passing the arg for 'show_next' or 'show_previous' so it'll show whichever image is current
+clear()
+show_image()
+portal.update(display)
+portal.update(display)
+
+while True:
+
+    # Poll the touch so we can see if anything changed since the last time
+    touch.poll()
+
+    # Check if it's time to update the image!
+    if time.time() - last_updated > INTERVAL:
+
+        last_updated = time.time()
+        show_image(show_next=True)
+        portal.update(display)
+
+    # if the screen is reporting that there is touch we want to handle that here
+    if touch.state:
+        # Right half of the screen moves to the next image
+        # The LEDs on the right side of the presto light up to show it is working
+        if touch.x > WIDTH // 2:
+            for i in LEDS_RIGHT:
+                bl.set_rgb(i, 255, 255, 255)
+            show_image(show_next=True)
+            portal.update(display)
+            last_updated = time.time()
+            for i in LEDS_RIGHT:
+                bl.set_rgb(i, 0, 0, 0)
+
+        # Left half of the screen moves to the previous image
+        elif touch.x < WIDTH // 2:
+            for i in LEDS_LEFT:
+                bl.set_rgb(i, 255, 255, 255)
+            show_image(show_previous=True)
+            portal.update(display)
+            last_updated = time.time()
+            for i in LEDS_LEFT:
+                bl.set_rgb(i, 0, 0, 0)
+
+        # Wait here until the user stops touching the screen
+        while touch.state:
+            touch.poll()
+            time.sleep(0.02)