Add rgb_hsv_conversion.py (#4334)

* Add rgb_hsv_conversion.py

* updating DIRECTORY.md

* snake-case

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: algobytewise

Diff for: DIRECTORY.md

@@ -112,6 +112,7 @@
   * [Molecular Chemistry](https://github.com/TheAlgorithms/Python/blob/master/conversions/molecular_chemistry.py)
   * [Octal To Decimal](https://github.com/TheAlgorithms/Python/blob/master/conversions/octal_to_decimal.py)
   * [Prefix Conversions](https://github.com/TheAlgorithms/Python/blob/master/conversions/prefix_conversions.py)
+  * [Rgb Hsv Conversion](https://github.com/TheAlgorithms/Python/blob/master/conversions/rgb_hsv_conversion.py)
   * [Roman Numerals](https://github.com/TheAlgorithms/Python/blob/master/conversions/roman_numerals.py)
   * [Temperature Conversions](https://github.com/TheAlgorithms/Python/blob/master/conversions/temperature_conversions.py)
   * [Weight Conversion](https://github.com/TheAlgorithms/Python/blob/master/conversions/weight_conversion.py)

Diff for: conversions/rgb_hsv_conversion.py

@@ -0,0 +1,159 @@
+"""
+The RGB color model is an additive color model in which red, green, and blue light
+are added together in various ways to reproduce a broad array of colors. The name
+of the model comes from the initials of the three additive primary colors, red,
+green, and blue. Meanwhile, the HSV representation models how colors appear under
+light. In it, colors are represented using three components: hue, saturation and
+(brightness-)value. This file provides functions for converting colors from one
+representation to the other.
+
+(description adapted from https://en.wikipedia.org/wiki/RGB_color_model and
+https://en.wikipedia.org/wiki/HSL_and_HSV).
+"""
+
+
+def hsv_to_rgb(hue: float, saturation: float, value: float) -> list[int]:
+    """
+    Conversion from the HSV-representation to the RGB-representation.
+    Expected RGB-values taken from
+    https://www.rapidtables.com/convert/color/hsv-to-rgb.html
+
+    >>> hsv_to_rgb(0, 0, 0)
+    [0, 0, 0]
+    >>> hsv_to_rgb(0, 0, 1)
+    [255, 255, 255]
+    >>> hsv_to_rgb(0, 1, 1)
+    [255, 0, 0]
+    >>> hsv_to_rgb(60, 1, 1)
+    [255, 255, 0]
+    >>> hsv_to_rgb(120, 1, 1)
+    [0, 255, 0]
+    >>> hsv_to_rgb(240, 1, 1)
+    [0, 0, 255]
+    >>> hsv_to_rgb(300, 1, 1)
+    [255, 0, 255]
+    >>> hsv_to_rgb(180, 0.5, 0.5)
+    [64, 128, 128]
+    >>> hsv_to_rgb(234, 0.14, 0.88)
+    [193, 196, 224]
+    >>> hsv_to_rgb(330, 0.75, 0.5)
+    [128, 32, 80]
+    """
+    if hue < 0 or hue > 360:
+        raise Exception("hue should be between 0 and 360")
+
+    if saturation < 0 or saturation > 1:
+        raise Exception("saturation should be between 0 and 1")
+
+    if value < 0 or value > 1:
+        raise Exception("value should be between 0 and 1")
+
+    chroma = value * saturation
+    hue_section = hue / 60
+    second_largest_component = chroma * (1 - abs(hue_section % 2 - 1))
+    match_value = value - chroma
+
+    if hue_section >= 0 and hue_section <= 1:
+        red = round(255 * (chroma + match_value))
+        green = round(255 * (second_largest_component + match_value))
+        blue = round(255 * (match_value))
+    elif hue_section > 1 and hue_section <= 2:
+        red = round(255 * (second_largest_component + match_value))
+        green = round(255 * (chroma + match_value))
+        blue = round(255 * (match_value))
+    elif hue_section > 2 and hue_section <= 3:
+        red = round(255 * (match_value))
+        green = round(255 * (chroma + match_value))
+        blue = round(255 * (second_largest_component + match_value))
+    elif hue_section > 3 and hue_section <= 4:
+        red = round(255 * (match_value))
+        green = round(255 * (second_largest_component + match_value))
+        blue = round(255 * (chroma + match_value))
+    elif hue_section > 4 and hue_section <= 5:
+        red = round(255 * (second_largest_component + match_value))
+        green = round(255 * (match_value))
+        blue = round(255 * (chroma + match_value))
+    else:
+        red = round(255 * (chroma + match_value))
+        green = round(255 * (match_value))
+        blue = round(255 * (second_largest_component + match_value))
+
+    return [red, green, blue]
+
+
+def rgb_to_hsv(red: int, green: int, blue: int) -> list[float]:
+    """
+    Conversion from the RGB-representation to the HSV-representation.
+    The tested values are the reverse values from the hsv_to_rgb-doctests.
+    Function "approximately_equal_hsv" is needed because of small deviations due to
+    rounding for the RGB-values.
+
+    >>> approximately_equal_hsv(rgb_to_hsv(0, 0, 0), [0, 0, 0])
+    True
+    >>> approximately_equal_hsv(rgb_to_hsv(255, 255, 255), [0, 0, 1])
+    True
+    >>> approximately_equal_hsv(rgb_to_hsv(255, 0, 0), [0, 1, 1])
+    True
+    >>> approximately_equal_hsv(rgb_to_hsv(255, 255, 0), [60, 1, 1])
+    True
+    >>> approximately_equal_hsv(rgb_to_hsv(0, 255, 0), [120, 1, 1])
+    True
+    >>> approximately_equal_hsv(rgb_to_hsv(0, 0, 255), [240, 1, 1])
+    True
+    >>> approximately_equal_hsv(rgb_to_hsv(255, 0, 255), [300, 1, 1])
+    True
+    >>> approximately_equal_hsv(rgb_to_hsv(64, 128, 128), [180, 0.5, 0.5])
+    True
+    >>> approximately_equal_hsv(rgb_to_hsv(193, 196, 224), [234, 0.14, 0.88])
+    True
+    >>> approximately_equal_hsv(rgb_to_hsv(128, 32, 80), [330, 0.75, 0.5])
+    True
+    """
+    if red < 0 or red > 255:
+        raise Exception("red should be between 0 and 255")
+
+    if green < 0 or green > 255:
+        raise Exception("green should be between 0 and 255")
+
+    if blue < 0 or blue > 255:
+        raise Exception("blue should be between 0 and 255")
+
+    float_red = red / 255
+    float_green = green / 255
+    float_blue = blue / 255
+    value = max(max(float_red, float_green), float_blue)
+    chroma = value - min(min(float_red, float_green), float_blue)
+    saturation = 0 if value == 0 else chroma / value
+
+    if chroma == 0:
+        hue = 0.0
+    elif value == float_red:
+        hue = 60 * (0 + (float_green - float_blue) / chroma)
+    elif value == float_green:
+        hue = 60 * (2 + (float_blue - float_red) / chroma)
+    else:
+        hue = 60 * (4 + (float_red - float_green) / chroma)
+
+    hue = (hue + 360) % 360
+
+    return [hue, saturation, value]
+
+
+def approximately_equal_hsv(hsv_1: list[float], hsv_2: list[float]) -> bool:
+    """
+    Utility-function to check that two hsv-colors are approximately equal
+
+    >>> approximately_equal_hsv([0, 0, 0], [0, 0, 0])
+    True
+    >>> approximately_equal_hsv([180, 0.5, 0.3], [179.9999, 0.500001, 0.30001])
+    True
+    >>> approximately_equal_hsv([0, 0, 0], [1, 0, 0])
+    False
+    >>> approximately_equal_hsv([180, 0.5, 0.3], [179.9999, 0.6, 0.30001])
+    False
+    """
+    check_hue = abs(hsv_1[0] - hsv_2[0]) < 0.2
+    check_saturation = abs(hsv_1[1] - hsv_2[1]) < 0.002
+    check_value = abs(hsv_1[2] - hsv_2[2]) < 0.002
+
+    return check_hue and check_saturation and check_value