tabs and tab overview

scripts/srgb.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+import argparse
+import math
+
+
+# Note: we use a pure gamma 2.2 function, rather than the piece-wise
+# sRGB transfer function, since that is what all compositors do.
+
+def srgb_to_linear(f: float) -> float:
+    assert(f >= 0 and f <= 1.0)
+    return math.pow(f, 2.2)
+
+
+def linear_to_srgb(f: float) -> float:
+    return math.pow(f, 1 / 2.2)
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('c_output', type=argparse.FileType('w'))
+    parser.add_argument('h_output', type=argparse.FileType('w'))
+    opts = parser.parse_args()
+
+    linear_table: list[int] = []
+
+    for i in range(256):
+        linear_table.append(int(srgb_to_linear(float(i) / 255) * 65535 + 0.5))
+
+
+    opts.h_output.write("#pragma once\n")
+    opts.h_output.write("#include <stdint.h>\n")
+    opts.h_output.write("\n")
+    opts.h_output.write('/* 8-bit input, 16-bit output */\n')
+    opts.h_output.write("extern const uint16_t srgb_decode_8_to_16_table[256];")
+
+    opts.h_output.write('\n')
+    opts.h_output.write('static inline uint16_t\n')
+    opts.h_output.write('srgb_decode_8_to_16(uint8_t v)\n')
+    opts.h_output.write('{\n')
+    opts.h_output.write('    return srgb_decode_8_to_16_table[v];\n')
+    opts.h_output.write('}\n')
+
+    opts.h_output.write('\n')
+    opts.h_output.write('/* 8-bit input, 8-bit output */\n')
+    opts.h_output.write("extern const uint8_t srgb_decode_8_to_8_table[256];\n")
+
+    opts.h_output.write('\n')
+    opts.h_output.write('static inline uint8_t\n')
+    opts.h_output.write('srgb_decode_8_to_8(uint8_t v)\n')
+    opts.h_output.write('{\n')
+    opts.h_output.write('    return srgb_decode_8_to_8_table[v];\n')
+    opts.h_output.write('}\n')
+
+    opts.c_output.write('#include "srgb.h"\n')
+    opts.c_output.write('\n')
+
+    opts.c_output.write("const uint16_t srgb_decode_8_to_16_table[256] = {\n")
+    for i in range(256):
+        opts.c_output.write(f'    {linear_table[i]},\n')
+    opts.c_output.write('};\n')
+
+    opts.c_output.write("const uint8_t srgb_decode_8_to_8_table[256] = {\n")
+    for i in range(256):
+        opts.c_output.write(f'    {linear_table[i] >> 8},\n')
+    opts.c_output.write('};\n')
+
+
+if __name__ == '__main__':
+    main()