adds kffview.py cli to view kff files

firmware/font/kffview.py

@@ -0,0 +1,120 @@
+#!/usr/bin/env python3
+"""
+A simple Krux Font Format viewer
+
+Pass it: font_filename.kff and height-in-pixels to view all fonts,
+optionally, pass it also [ one_utf_character ] to see just that glyph
+"""
+
+# The MIT License (MIT)
+
+# Copyright (c) 2021-2023 Krux contributors
+
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+
+def str_to_bytes(comma_separated_bytes_string):
+    """
+    receives a string like "0x00,0xff" returning bytes like b'\x00\xff'
+    """
+    bytestr_list = comma_separated_bytes_string.split(",")
+    validation = [x[:2] == "0x" and len(x) == 4 for x in bytestr_list]
+    assert set(validation) == set([True])
+    return bytes([int(x[2:], 16) for x in bytestr_list])
+
+
+def main(kff_filename, height, chars=[]):
+    """
+    receives a kff-filename, height and optionally a string of characters
+    prints all kff bitmap fonts, or those requested, to stdout.
+    """
+    height = int(height)
+    zero = chr(0x2591) * 2  # display zero bits as two light-shade chars
+    one = chr(0x2588) * 2  # display one bits as two full-block chars
+
+    with open(kff_filename, "r", encoding="ascii") as file_handle:
+        contents = file_handle.read().replace("\n", "")
+    contents = str_to_bytes(contents)
+
+    num_glyphs = int.from_bytes(contents[:2], "big")
+    assert (len(contents) - 2) % num_glyphs == 0
+    bytes_per_glyph = (len(contents) - 2) // num_glyphs
+    assert (bytes_per_glyph - 2) % height == 0
+
+    print(f"{kff_filename} contains {num_glyphs:d} glyphs:")
+    for i in range(2, len(contents), bytes_per_glyph):
+        glyph = contents[i : i + bytes_per_glyph]
+        codepoint = int.from_bytes(glyph[:2], "big")
+        byte_map = glyph[2:]
+        bit_map = "".join([f"{x:08b}" for x in byte_map])
+
+        if chars and chr(codepoint) not in chars:
+            continue
+
+        print(f'\n"{chr(codepoint)}" is unicode: U+{codepoint:04X}, decimal: {codepoint:d}')
+        if len(byte_map) == height:
+            # one 8 bit column
+            for i in range(0, len(bit_map), 8):
+                print("".join(one if x == "1" else zero for x in bit_map[i : i + 8]))
+
+        elif len(byte_map) == height*2:
+            # two 8 bit columns
+            half = int(len(bit_map) / 2)
+            for i in range(0, half, 8):
+                print(
+                    "".join(
+                        one if x == "1" else zero
+                        for x in bit_map[i : i + 8] + bit_map[half + i : half + i + 8]
+                    )
+                )
+        elif len(byte_map) == height*3:
+            # three 8 bit columns
+            third = int(len(bit_map) / 3)
+            for i in range(0, third, 8):
+                print(
+                    "".join(
+                        one if x == "1" else zero
+                        for x in (
+                            bit_map[i : i + 8] +
+                            bit_map[third + i : third + i + 8] +
+                            bit_map[2 * third + i : 2 * third + i + 8]
+                        )
+                    )
+                )
+        elif len(byte_map) == height*4:
+            # four 8 bit columns
+            qtr = int(len(bit_map) / 4)
+            for i in range(0, qtr, 8):
+                print(
+                    "".join(
+                        one if x == "1" else zero
+                        for x in (
+                            bit_map[i : i + 8] +
+                            bit_map[qtr + i : qtr + i + 8] +
+                            bit_map[2 * qtr + i : 2 * qtr + i + 8] +
+                            bit_map[3 * qtr + i : 3 * qtr + i + 8]
+                        )
+                    )
+                )
+
+
+if __name__ == "__main__":
+    import sys
+
+    main(*sys.argv[1:])