WIP

examples/tanks/gems.rb

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+source "https://rubygems.org"
+
+gem "live"
+gem "lively", path: "../../"
+
+gem "activerecord", "~> 7.1"
+gem "sqlite3", "~> 1.4"
+gem "markly"
+
+gem "base64"

examples/tanks/png.rb

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+require 'zlib'
+
+module PNG
+	def self.greyscale(width, height, data)
+		# PNG file signature
+		png_signature = "\x89PNG\r\n\x1a\n".b
+
+		# IHDR chunk
+		bit_depth = 8  # 8 bits per pixel
+		color_type = 0  # Greyscale
+		compression_method = 0
+		filter_method = 0
+		interlace_method = 0
+
+		ihdr_data = [width, height, bit_depth, color_type, compression_method, filter_method, interlace_method].pack('N2C5')
+		ihdr_crc = Zlib.crc32("IHDR" + ihdr_data)
+		ihdr_chunk = [ihdr_data.bytesize].pack('N') + "IHDR" + ihdr_data + [ihdr_crc].pack('N')
+
+		# IDAT chunk
+		raw_data = ""
+		height.times do |y|
+			row = data.get_string(y * width, width)
+			raw_data << "\x00" + row
+		end
+
+		# Compress data with no compression (just to fit PNG structure)
+		compressed_data = Zlib::Deflate.deflate(raw_data, Zlib::NO_COMPRESSION)
+		idat_crc = Zlib.crc32("IDAT" + compressed_data)
+		idat_chunk = [compressed_data.bytesize].pack('N') + "IDAT" + compressed_data + [idat_crc].pack('N')
+
+		# IEND chunk
+		iend_crc = Zlib.crc32("IEND")
+		iend_chunk = [0].pack('N') + "IEND" + [iend_crc].pack('N')
+
+		# Combine all parts into the final PNG
+		return png_signature + ihdr_chunk + idat_chunk + iend_chunk
+	end
+end

examples/tanks/public/_static/index.css

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+/* Center the table in the page */
+
+body {
+	display: flex;
+	justify-content: center;
+	align-items: center;
+	height: 100vh;
+	margin: 0;
+}
+
+/* Make a table display as a regular size 10px x 10px per cell */
+
+table {
+	border-collapse: collapse;
+	border-spacing: 0;
+}
+
+td {
+	width: 2rem;
+	height: 2rem;
+	padding: 0;
+	margin: 0;
+	border: 1px solid black;
+
+	/* Center the character in the cell */
+	text-align: center;
+	vertical-align: middle;
+}