From 6017481d736fd3ae7aa8b1055913e873c0d514c6 Mon Sep 17 00:00:00 2001
From: Loek Le Blansch <loek@pipeframe.xyz>
Date: Fri, 4 Oct 2024 23:53:16 +0200
Subject: implement png2pc

---
 experiments/conv/consts.py | 38 ++++++++++++++++++-------------
 experiments/conv/makefile  |  2 ++
 experiments/conv/pc2png    | 26 +++------------------
 experiments/conv/png2pc    | 56 ++++++++++++++++++++++++++++++++++++++++++++++
 experiments/conv/shared.py | 19 ++++++++++++++++
 5 files changed, 102 insertions(+), 39 deletions(-)
 create mode 100644 experiments/conv/makefile
 create mode 100755 experiments/conv/png2pc
 create mode 100644 experiments/conv/shared.py

diff --git a/experiments/conv/consts.py b/experiments/conv/consts.py
index 898bd3d..e50c51a 100644
--- a/experiments/conv/consts.py
+++ b/experiments/conv/consts.py
@@ -1,18 +1,24 @@
+DS_TILE_SIZE = 8
+TILE_BYTES = 32 # tiles are stored in 32 bytes chunks
+
+TILES_HORIZONTAL = 32
+
 PICTOCHAT_PALETTE = (
-  (0xff, 0xff, 0xff),
-  (0x00, 0x00, 0x00),
-  (0xd3, 0xcb, 0xc3),
-  (0xeb, 0x00, 0xeb),
-  (0xfb, 0x00, 0x8a),
-  (0xfb, 0x00, 0x28),
-  (0xfb, 0x49, 0x00),
-  (0xfb, 0xa2, 0x00),
-  (0xe3, 0xf3, 0x00),
-  (0x82, 0xfb, 0x00),
-  (0x10, 0xfb, 0x20),
-  (0x00, 0xfb, 0xba),
-  (0x00, 0xc3, 0xfb),
-  (0x00, 0x79, 0xfb),
-  (0x00, 0x30, 0xfb),
-  (0x28, 0x00, 0xfb),
+	(0xff, 0xff, 0xff),
+	(0x00, 0x00, 0x00),
+	(0xd3, 0xcb, 0xc3),
+	(0xeb, 0x00, 0xeb),
+	(0xfb, 0x00, 0x8a),
+	(0xfb, 0x00, 0x28),
+	(0xfb, 0x49, 0x00),
+	(0xfb, 0xa2, 0x00),
+	(0xe3, 0xf3, 0x00),
+	(0x82, 0xfb, 0x00),
+	(0x10, 0xfb, 0x20),
+	(0x00, 0xfb, 0xba),
+	(0x00, 0xc3, 0xfb),
+	(0x00, 0x79, 0xfb),
+	(0x00, 0x30, 0xfb),
+	(0x28, 0x00, 0xfb),
 )
+
diff --git a/experiments/conv/makefile b/experiments/conv/makefile
new file mode 100644
index 0000000..f4f3cd5
--- /dev/null
+++ b/experiments/conv/makefile
@@ -0,0 +1,2 @@
+%.png: %.bin
+	./pc2png $<
diff --git a/experiments/conv/pc2png b/experiments/conv/pc2png
index 4fa7a1a..c7f131a 100755
--- a/experiments/conv/pc2png
+++ b/experiments/conv/pc2png
@@ -1,18 +1,10 @@
 #!/bin/python3
-
-import sys
-import re
 import math
 import io
-
 from PIL import Image
 
-from consts import PICTOCHAT_PALETTE
-
-DS_TILE_SIZE = 8
-TILE_BYTES = 32 # tiles are stored in 32 bytes chunks
-
-TILES_HORIZONTAL = 32
+from consts import *
+from shared import main
 
 # convert a single DS tile (8x8) from packed palette index format to RGB colors
 def convert_chunk(img, chunk, offset):
@@ -53,18 +45,6 @@ def pc2png(data):
 	img.save(output, format='PNG')
 	return output.getvalue()
 
-def convert_file(input_filename, output_filename):
-	with open(input_filename, 'rb') as input_file:
-		content = input_file.read()
-		output = pc2png(content)
-		with open(output_filename, 'wb+') as output_file:
-			output_file.write(output)
-
 if __name__ == "__main__":
-	del sys.argv[0]
-	for input_filename in sys.argv:
-		output_filename = re.sub('.bin$', '.png', input_filename)
-		if not output_filename.endswith('.png'):
-			output_filename += '.png'
-		convert_file(input_filename, output_filename)
+	main("bin", "png", pc2png)
 
diff --git a/experiments/conv/png2pc b/experiments/conv/png2pc
new file mode 100755
index 0000000..d1eaab8
--- /dev/null
+++ b/experiments/conv/png2pc
@@ -0,0 +1,56 @@
+#!/bin/python3
+import itertools
+import io
+from PIL import Image
+
+from consts import *
+from shared import main
+
+palette_img = Image.new('P', (1, 1))
+palette_img.putpalette(list(itertools.chain.from_iterable([
+	*PICTOCHAT_PALETTE,
+	*[PICTOCHAT_PALETTE[0] for x in range(256 - len(PICTOCHAT_PALETTE))],
+])))
+
+def convert_chunk(img, offset):
+	palette_indices = []
+	for y in range(DS_TILE_SIZE):
+		for x in range(DS_TILE_SIZE):
+			palette_indices.append(img.getpixel((x + offset[0], y + offset[1])))
+
+	bytes = bytearray()
+	for i in range(0, len(palette_indices), 2):
+		bytes.append((palette_indices[i+0] << 0) | (palette_indices[i+1] << 4))
+	
+	return bytes
+
+def png2pc(data):
+	img = Image.open(io.BytesIO(data))
+	if img.width != TILES_HORIZONTAL * DS_TILE_SIZE:
+		print(f"error: input image is not {TILES_HORIZONTAL * DS_TILE_SIZE} pixels wide")
+		exit(1)
+	if img.height % DS_TILE_SIZE != 0:
+		print(f"error: input image height not a muliple of {DS_TILE_SIZE}")
+		exit(1)
+	tile_count = (img.width * img.height) // (DS_TILE_SIZE ** 2)
+	
+	img = img.convert('RGB')
+	img = img.quantize(palette=palette_img)
+
+	output = b""
+	for tile_idx in range(tile_count):
+		tile = (
+			tile_idx % TILES_HORIZONTAL,
+			tile_idx // TILES_HORIZONTAL,
+		)
+		offset = (
+			tile[0] * DS_TILE_SIZE,
+			tile[1] * DS_TILE_SIZE,
+		)
+		output += convert_chunk(img, offset)
+
+	return output
+
+if __name__ == "__main__":
+	main("png", "bin", png2pc)
+
diff --git a/experiments/conv/shared.py b/experiments/conv/shared.py
new file mode 100644
index 0000000..be883be
--- /dev/null
+++ b/experiments/conv/shared.py
@@ -0,0 +1,19 @@
+import sys
+
+def convert_file(input_filename, output_filename, converter):
+	with open(input_filename, 'rb') as input_file:
+		content = input_file.read()
+		output = converter(content)
+		with open(output_filename, 'wb+') as output_file:
+			output_file.write(output)
+
+def main(from_ext, to_ext, converter):
+	del sys.argv[0]
+	if len(sys.argv) == 0:
+		print("error: no input files!", file=sys.stderr)
+		exit(1)
+
+	for input_filename in sys.argv:
+		output_filename = input_filename.removesuffix(f".{from_ext}") + f".{to_ext}"
+		convert_file(input_filename, output_filename, converter)
+
-- 
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