WIP SHR snowflake effect (not hooked up)

res/notes/transitions/shr_snowflake.py

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+#!/usr/bin/env python3
+
+import PIL.Image # https://pillow.readthedocs.io/
+import util
+
+# snowflake.png is the source image. The source image MUST have a white background,
+# but other colors and pixel depth are irrelevant. This one is black & white.
+# Due to the Apple II pixel aspect ratio, we do a 1-time aspect-ratio-losing resize
+# to squash the image to 92% height.
+#
+# $ gm convert snowflake.png -resize "100%x92%!" squash.png
+# (Depending on your shell, you may need to escape the exclamation point. Grr.)
+#
+# Now we can create individual images for each "frame" of the animation, by
+# resizing the (squashed) source image and putting it in a 280x192 frame.
+#
+# $ for w in `seq 1 500`; do \
+#     gm convert -size 160x100 squash.png \
+#                -resize "$w" \
+#                -background white \
+#                -compose Copy \
+#                -gravity center \
+#                -extent 160x100 thumb"$w".png; \
+#   done
+#
+# Depending on the source image, you may need more or fewer than 500 frames. This
+# number is duplicated below in the |frames| variable. Sorry.
+#
+
+frames = 500 # number of "thumbN.png" files
+
+coords = []
+for i in range(1,frames):
+    p = PIL.Image.open("snowflake/thumb%s.png" % i)
+    for x in range(0, 160//2):
+        for y in range(0, 100//2):
+            if p.getpixel((x,99-y))[0] != 255:
+                coords.append((y*2,x))
+
+unique_coords = util.unique(coords)
+
+util.write("../../../src/fx/fx.shr.snowflake.data.a", unique_coords, header="""!cpu 6502
+!to "build/FX/SHR.FLAKE.DATA",plain
+*=$9F00
+""")

src/fx/fx.shr.snowflake.a

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+;license:MIT
+;(c) 2021 by 4am
+;
+!cpu 6502
+;!to "build/FX.INDEXED/SHR.SNOWFLAKE",plain
+*=$A000
+
+         !source "src/fx/fx.shr.precomputed.a"
+
+CoordinatesFile
+         !byte 17
+         !text "FX/SHR.FLAKE.DATA"