Merge pull request #181 from Wacky404/feature/css_files_to_html_str

feat: added the ability for css_files to be used on html_str when using screenshot function.

Author: vgalin

README.md

@@ -359,7 +359,7 @@ If you want to contribute to `html2image` or run tests locally, follow these ste
 
 4.  **Install dependencies (including development tools):**
     ```bash
-    uv pip install -e .[dev]
+    uv pip install -e ".[dev]"
     ```
     This installs the package in editable mode along with all dependencies needed for testing and linting.
 

html2image/html2image.py

@@ -421,6 +421,29 @@ def _prepare_html_string(html_body, css_style_string):
         """
         return dedent(prepared_html)
 
+    @staticmethod
+    def _prepare_css_str(css_file):
+        """ Creates a basic string fromatted from a css file.
+
+        Parameters
+        ----------
+        - `css_file`: str
+
+        Returns
+        -------
+        - str
+            The contents of each css file.
+
+        """
+        css_str = ""
+        for css in css_file:
+            temp_css_str = ''
+            with open(css, "r") as fd:
+                temp_css_str = fd.read()
+                css_str += temp_css_str + '\n'
+
+        return css_str
+
     def screenshot(
         self,
         html_str=[],  # html_str: Union[str, list] = [],
@@ -515,7 +538,8 @@ def screenshot(
             base_name, _ = os.path.splitext(name)
             html_filename = base_name + '.html'
             content = Html2Image._prepare_html_string(
-                html, css_style_string
+                html, css_style_string if css_style_string != '' else Html2Image._prepare_css_str(
+                    css_file)
             )
             self.load_str(content=content, as_filename=html_filename)
             self.screenshot_loaded_file(