initial commit

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

colorhash/__main__.py

@@ -0,0 +1,114 @@
+import hashlib
+import sys
+
+
+# TODO - WASM compile for embedding directly in HTML
+# TODO - command line parsing for hash type, infile, forcing a palette, etc
+# TODO - file streaming for infile so we aren't loading e.g. 4GB into memory unnecessarily
+
+
+def hash2matrix(data: bytes, w: int, h: int) -> list[list[int]]:
+    """
+    Convert a hash to a list of rows of nibbles.
+    """
+    # Split the data into nibbles first, in case the width is an odd number
+    nibbles = []
+    for b in data:
+        top = (b & 0xF0) >> 4
+        bottom = b & 0x0F
+        nibbles += [top, bottom]
+
+    if len(nibbles) != w * h:
+        raise ValueError(
+            f"input data length ({len(nibbles)}) must match matrix dimensions ({w}x{h} = {w * h})"
+        )
+
+    cols = []
+    row = []
+    for b in nibbles:
+        row += [b]
+        if len(row) == w:
+            cols += [row]
+            row = []
+
+    return cols
+
+
+def gensvg(matrix: list[list[int]], square_size: int = 32):
+    h = len(matrix)
+    w = len(matrix[0])
+
+    # Start SVG string
+    svg = f'<svg width="{w * square_size}" height="{h * square_size}" xmlns="http://www.w3.org/2000/svg">\n'
+
+    # Generate grid
+    for r in range(h):
+        for c in range(w):
+            x = c * square_size
+            y = r * square_size
+            color = matrix[r][c]
+            svg += f'  <rect x="{x}" y="{y}" width="{square_size}" height="{square_size}" fill="{color}" />\n'
+
+    # Close SVG string
+    svg += "</svg>"
+    return svg
+
+
+color_table = [
+    # red
+    [f"#{0x110000 * i:06x}" for i in range(0x10)],
+    # green
+    [f"#{0x001100 * i:06x}" for i in range(0x10)],
+    # blue
+    [f"#{0x000011 * i:06x}" for i in range(0x10)],
+    # black
+    [f"#{0x111111 * i:06x}" for i in range(0x10)],
+    # cyan
+    [f"#{0x001111 * i:06x}" for i in range(0x10)],
+    # yellow
+    [f"#{0x111100 * i:06x}" for i in range(0x10)],
+    # magenta
+    [f"#{0x110011 * i:06x}" for i in range(0x10)],
+    # white
+    [f"#{0x111111 * (0xF - i):06x}" for i in range(0x10)],
+]
+
+dimensions_table = {
+    "md5": (8, 4),
+    "sha1": (8, 5),
+    "sha224": (8, 7),
+    "sha256": (8, 8),
+    "sha384": (12, 8),
+    "sha512": (16, 8),
+}
+
+
+hash_algo = "sha512"
+
+infile = sys.stdin.buffer
+
+
+if len(sys.argv) > 1:
+    inpath = sys.argv[1]
+    if inpath != '-':
+        infile = open(inpath, 'rb')
+
+
+hashdata = hashlib.file_digest(infile, hash_algo).digest()
+w, h = dimensions_table[hash_algo]
+matrix = hash2matrix(hashdata, w, h)
+
+# Print matrix
+# pprint.pprint([[hex(c) for c in row] for row in matrix])
+
+palette_no = sum(hashdata) % 8
+# print('using palette:', palette_no)
+palette = color_table[palette_no]
+
+colors = [[palette[v] for v in row] for row in matrix]
+
+# Print colors
+# pprint.pprint([[hex(c) for c in row] for row in colors])
+
+# Print SVG
+print(gensvg(colors))