feat: support for custom colors (#76)

* support for custom colors

* linting fixed

* really fixed linting for flake8.

---------

Co-authored-by: dshaw0004 <dipankarshaw692@gmail.com>

Author: dshaw0004

README.md

@@ -41,6 +41,21 @@ image.write('1234', 'out.png')
 This is the APIs for your daily works. We do have built-in voice data and font
 data. But it is suggested that you use your own voice and font data.
 
+### Use Custom Colors
+
+In order to change colors you have to specify your desired color as a tuple of Red, Green and Blue value.
+Example:- `(255, 255, 0)` for yellow color, (255, 0, 0)` for red color.
+
+```python
+from captcha.image import ImageCaptcha
+
+image = ImageCaptcha(fonts=['/path/A.ttf', '/path/B.ttf'])
+
+data = image.generate('1234')
+image.write('1234', 'out.png', bg_color=(255, 255, 0), fg_color=(255, 0, 0)) # red text in yellow background
+```
+
+
 ## Useful Links
 
 1. GitHub: https://github.com/lepture/captcha

src/captcha/image.py

@@ -187,39 +187,53 @@ def create_captcha_image(
 
         return image
 
-    def generate_image(self, chars: str) -> Image:
+    def generate_image(self, chars: str,
+                       bg_color: ColorTuple | None = None,
+                       fg_color: ColorTuple | None = None) -> Image:
         """Generate the image of the given characters.
 
         :param chars: text to be generated.
+        :param bg_color: background color of the image in rgb format (r, g, b).
+        :param fg_color: foreground color of the text in rgba format (r,g,b,a).
         """
-        background = random_color(238, 255)
-        color = random_color(10, 200, random.randint(220, 255))
+        background = bg_color if bg_color else random_color(238, 255)
+        random_fg_color = random_color(10, 200, random.randint(220, 255))
+        color: ColorTuple = fg_color if fg_color else random_fg_color
+
         im = self.create_captcha_image(chars, color, background)
         self.create_noise_dots(im, color)
         self.create_noise_curve(im, color)
         im = im.filter(SMOOTH)
         return im
 
-    def generate(self, chars: str, format: str = 'png') -> BytesIO:
+    def generate(self, chars: str, format: str = 'png',
+                 bg_color: ColorTuple | None = None,
+                 fg_color: ColorTuple | None = None) -> BytesIO:
         """Generate an Image Captcha of the given characters.
 
         :param chars: text to be generated.
         :param format: image file format
+        :param bg_color: background color of the image in rgb format (r, g, b).
+        :param fg_color: foreground color of the text in rgba format (r,g,b,a).
         """
-        im = self.generate_image(chars)
+        im = self.generate_image(chars, bg_color=bg_color, fg_color=fg_color)
         out = BytesIO()
         im.save(out, format=format)
         out.seek(0)
         return out
 
-    def write(self, chars: str, output: str, format: str = 'png') -> None:
+    def write(self, chars: str, output: str, format: str = 'png',
+              bg_color: ColorTuple | None = None,
+              fg_color: ColorTuple | None = None) -> None:
         """Generate and write an image CAPTCHA data to the output.
 
         :param chars: text to be generated.
         :param output: output destination.
         :param format: image file format
+        :param bg_color: background color of the image in rgb format (r, g, b).
+        :param fg_color: foreground color of the text in rgba format (r,g,b,a).
         """
-        im = self.generate_image(chars)
+        im = self.generate_image(chars, bg_color=bg_color, fg_color=fg_color)
         im.save(output, format=format)