From 99379a9835195760b4b7b35eb21773a24eccff18 Mon Sep 17 00:00:00 2001
From: Marek Mazij <112333347+Mrk-Mzj@users.noreply.github.com>
Date: Sat, 21 Oct 2023 02:30:08 +0200
Subject: [PATCH 1/3] feat: code functional, commented, tested

---
 conversions/rgb_cmyk_conversion.py | 68 ++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 conversions/rgb_cmyk_conversion.py

diff --git a/conversions/rgb_cmyk_conversion.py b/conversions/rgb_cmyk_conversion.py
new file mode 100644
index 000000000000..acecf41f757b
--- /dev/null
+++ b/conversions/rgb_cmyk_conversion.py
@@ -0,0 +1,68 @@
+def rgb_to_cmyk(r_input, g_input, b_input: int) -> tuple[int, int, int, int]:
+    """
+    Simple RGB to CMYK conversion. Returns percentages of CMYK paint.
+    https://www.programmingalgorithms.com/algorithm/rgb-to-cmyk/
+
+    Note: this is a very popular algorithm that converts colors linearly and gives
+    only approximate results. Actual preparation for printing requires advanced color
+    conversion considering the color profiles and parameters of the target device.
+
+    >>> rgb_to_cmyk(255, 200, "a")
+    Traceback (most recent call last):
+        ...
+    ValueError: Expected int as input, found (<class 'int'>, <class 'int'>, <class 'str'>)
+
+    >>> rgb_to_cmyk(255, 255, 999)
+    Traceback (most recent call last):
+        ...
+    ValueError: Expected int of the range 0..255
+
+    >>> rgb_to_cmyk(255, 255, 255)  # white
+    (0, 0, 0, 0)
+
+    >>> rgb_to_cmyk(128, 128, 128)  # gray
+    (0, 0, 0, 50)
+
+    >>> rgb_to_cmyk(0, 0, 0)    # black
+    (0, 0, 0, 100)
+
+    >>> rgb_to_cmyk(255, 0, 0)  # red
+    (0, 100, 100, 0)
+
+    >>> rgb_to_cmyk(0, 255, 0)  # green
+    (100, 0, 100, 0)
+
+    >>> rgb_to_cmyk(0, 0, 255)    # blue
+    (100, 100, 0, 0)
+    """
+
+    if type(r_input) != int or type(g_input) != int or type(b_input) != int:
+        raise ValueError(
+            f"Expected int as input, found {type(r_input), type(g_input), type(b_input)}"
+        )
+
+    if not 0 <= r_input < 256 or not 0 <= g_input < 256 or not 0 <= b_input < 256:
+        raise ValueError("Expected int of the range 0..255")
+
+    # changing range from 0..255 to 0..1
+    r = r_input / 255
+    g = g_input / 255
+    b = b_input / 255
+
+    k = 1 - max(r, g, b)
+
+    if k == 1:  # pure black
+        return 0, 0, 0, 100
+
+    c = round(100 * (1 - r - k) / (1 - k))
+    m = round(100 * (1 - g - k) / (1 - k))
+    y = round(100 * (1 - b - k) / (1 - k))
+    k = round(100 * k)
+
+    return c, m, y, k
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()

From 75979fb7c2d04b3e9d675eb6aa889a9fac8c0be9 Mon Sep 17 00:00:00 2001
From: Marek Mazij <112333347+Mrk-Mzj@users.noreply.github.com>
Date: Sat, 21 Oct 2023 03:08:26 +0200
Subject: [PATCH 2/3] fix: compering types, exception msg, line length

---
 conversions/rgb_cmyk_conversion.py | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/conversions/rgb_cmyk_conversion.py b/conversions/rgb_cmyk_conversion.py
index acecf41f757b..740f3db1b4ab 100644
--- a/conversions/rgb_cmyk_conversion.py
+++ b/conversions/rgb_cmyk_conversion.py
@@ -10,7 +10,7 @@ def rgb_to_cmyk(r_input, g_input, b_input: int) -> tuple[int, int, int, int]:
     >>> rgb_to_cmyk(255, 200, "a")
     Traceback (most recent call last):
         ...
-    ValueError: Expected int as input, found (<class 'int'>, <class 'int'>, <class 'str'>)
+    ValueError: Expected int, found (<class 'int'>, <class 'int'>, <class 'str'>)
 
     >>> rgb_to_cmyk(255, 255, 999)
     Traceback (most recent call last):
@@ -36,10 +36,13 @@ def rgb_to_cmyk(r_input, g_input, b_input: int) -> tuple[int, int, int, int]:
     (100, 100, 0, 0)
     """
 
-    if type(r_input) != int or type(g_input) != int or type(b_input) != int:
-        raise ValueError(
-            f"Expected int as input, found {type(r_input), type(g_input), type(b_input)}"
-        )
+    if (
+        not isinstance(r_input, int)
+        or not isinstance(g_input, int)
+        or not isinstance(b_input, int)
+    ):
+        msg = f"Expected int, found {type(r_input), type(g_input), type(b_input)}"
+        raise ValueError(msg)
 
     if not 0 <= r_input < 256 or not 0 <= g_input < 256 or not 0 <= b_input < 256:
         raise ValueError("Expected int of the range 0..255")

From 063e2c45364f2d470ce940c13135f8715fe380af Mon Sep 17 00:00:00 2001
From: Marek Mazij <112333347+Mrk-Mzj@users.noreply.github.com>
Date: Sat, 21 Oct 2023 03:13:38 +0200
Subject: [PATCH 3/3] fix: type hints

---
 conversions/rgb_cmyk_conversion.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/conversions/rgb_cmyk_conversion.py b/conversions/rgb_cmyk_conversion.py
index 740f3db1b4ab..07d65b704c44 100644
--- a/conversions/rgb_cmyk_conversion.py
+++ b/conversions/rgb_cmyk_conversion.py
@@ -1,4 +1,4 @@
-def rgb_to_cmyk(r_input, g_input, b_input: int) -> tuple[int, int, int, int]:
+def rgb_to_cmyk(r_input: int, g_input: int, b_input: int) -> tuple[int, int, int, int]:
     """
     Simple RGB to CMYK conversion. Returns percentages of CMYK paint.
     https://www.programmingalgorithms.com/algorithm/rgb-to-cmyk/