Add CircuitPython RLCD migration prototype

circuitpython/lib/gif_player.py

@@ -0,0 +1,48 @@
+"""GIF playback helper for the custom RLCD CircuitPython driver."""
+
+import gc
+import time
+
+import gifio
+
+
+class GIFPlayer:
+    def __init__(self, display):
+        self.display = display
+
+    def play(self, filename, *, loops=1, x=40, y=0, threshold=1, clear_between_frames=False):
+        """Decode a GIF from disk and push frames to the reflective LCD.
+
+        CircuitPython gifio currently supports GIFs up to 320 pixels wide, so
+        x defaults to 40 to center a 320-wide GIF on this 400-wide display.
+        The ST7305/RLCD display is monochrome in this project, so frames are
+        thresholded from palette indexes: palette index 0 is white; any index
+        >= threshold is black.
+        """
+        gif = gifio.OnDiskGif(filename)
+        try:
+            count = 0
+            while loops < 0 or count < loops:
+                while True:
+                    delay = gif.next_frame()
+                    if delay is None:
+                        break
+                    if clear_between_frames:
+                        self.display.clear(0)
+                    self.display.draw_bitmap_threshold(gif.bitmap, x, y, threshold=threshold)
+                    self.display.show()
+                    # gifio delay is seconds in modern CircuitPython builds. If
+                    # an older build plays 100x too slowly, divide by 100 here.
+                    time.sleep(max(0.0, delay))
+                count += 1
+                if loops < 0 or count < loops:
+                    # OnDiskGif has no reliable seek/rewind API; reopen to loop.
+                    gif.deinit()
+                    gc.collect()
+                    gif = gifio.OnDiskGif(filename)
+        finally:
+            try:
+                gif.deinit()
+            except AttributeError:
+                pass
+            gc.collect()