Ability to set image as GDM background

Closes #40.

README.md

@@ -79,6 +79,9 @@ Icon theme: https://github.com/vinceliuice/Colloid-icon-theme
 ## 🖥️ GDM theme
 
 ![GDM theme](./readme-images/gdm.png)
+> **Image:** [Network Abstract](https://4kwallpapers.com/abstract/network-abstract-background-blue-background-5k-8k-8270.html).
+> 
+> **Config:** `sudo python install.py --gdm --blue --gdm-image /path/to/image.jpg --gdm-blur=40 --gdm-darken=30`
 
 > [!NOTE]  
 > This theme only supports GNOME Display Manager. Ubuntu Display Manager is currently not supported.
@@ -86,9 +89,9 @@ Icon theme: https://github.com/vinceliuice/Colloid-icon-theme
 > [!WARNING]  
 > I am not responsible for any damage caused by the installation of the theme. If you have any problems, please open an issue.
 
-> [!IMPORTANT]  
-> Install `glib2-devel` package before running the program. 
-> For Debian-based systems, use the `libglib2.0-dev` package.
+### 🚧 Additional requirements
+- `glib2-devel` (`libglib2.0-dev` on Debian-based distros).
+- `imagemagick` (if you want to apply filters to the background image).
 
 1. Open the terminal.
 2. Go to the directory with the theme.
@@ -100,6 +103,9 @@ Icon theme: https://github.com/vinceliuice/Colloid-icon-theme
         ```shell
         sudo python install.py --gdm --blue --filled
         ```
+        ```shell
+        sudo python install.py --gdm --gray --gdm-image /path/to/image.jpg --gdm-blur=40 --gdm-darken=30
+        ```
 4. After successful file restart GDM service:
    ```shell
    sudo systemctl restart gdm
@@ -153,6 +159,15 @@ Icon theme: https://github.com/vinceliuice/Colloid-icon-theme
 | --mode | light / dark     | light / dark theme only                                    |
 | --sat  | (0 - 250)        | custom color saturation (<100% - reduce, >100% - increase) |
 
+#### GDM tweaks
+
+| Option        | Secondary option         | Description                 |
+|---------------|--------------------------|-----------------------------|
+| --gdm-image   | /absolute/path/to/image/ | set background image to GDM |
+| --gdm-blur    | 0+                       | apply blur to image (px)    |
+| --gdm-darken  | 0 - 100                  | darken image (%)            |
+| --gdm-lighten | 0 - 100                  | lighten image (%)           |
+
 #### Panel tweaks
 
 **Panel default size**
@@ -182,10 +197,11 @@ Icon theme: https://github.com/vinceliuice/Colloid-icon-theme
 
 #### Examples
 | Command                                                   | Description                                                              |
-|------------------------------------------------|----------------------------------------------------------------------|
+|-----------------------------------------------------------|--------------------------------------------------------------------------|
 | -a                                                        | Install all accent colors with light & dark mode                         |
 | --all --mode dark                                         | Install all accent colors with dark mode only                            |
 | --purple --mode=light                                     | Install purple accent color with light mode only                         |
 | --hue 150 --name coldgreen                                | Install custom coldgreen accent color, light & dark mode                 |
 | --red --green --sat=70                                    | red, green accent colors, 70% of the stock saturation                    |
 | --hue=200 --name=grayblue --sat=50 --mode=dark            | custom grayblue accent color, 50% of the stock saturation, dark mode     |
+| --gdm --blue --gdm-image /path/to/image.jpg --gdm-blur=40 | Install GDM theming in blue color with own GDM background image and blur |

install.py

@@ -16,6 +16,7 @@
 
 import json       # working with json files
 import argparse   # command-line options
+import os.path
 import shutil
 import textwrap   # example text in argparse
 
@@ -155,10 +156,10 @@ def global_theme(args, colors):
     :param args: parsed arguments
     :param colors: colors from colors.json
     """
-
+    gdm_temp = os.path.join(config.temp_folder, config.gdm_folder)
     gdm_theme = GlobalTheme(colors, f"{config.raw_theme_folder}/{config.gnome_folder}",
                             config.global_gnome_shell_theme, config.gnome_shell_gresource,
-                            config.temp_folder, mode=args.mode, is_filled=args.filled)
+                            gdm_temp, mode=args.mode, is_filled=args.filled)
 
     if args.remove:
         gdm_rm_status = gdm_theme.remove()
@@ -166,6 +167,8 @@ def global_theme(args, colors):
             print("GDM theme removed successfully.")
         return
 
+    for theme in gdm_theme.themes:
+        apply_tweaks(args, theme.theme, colors)
 
     if apply_colors(args, gdm_theme, colors, gdm=True) is None:
         print("\nGDM theme installed successfully.")

scripts/config.py

@@ -2,6 +2,7 @@ from tempfile import gettempdir
 
 # folder definitions
 temp_folder = f"{gettempdir()}/marble"
+gdm_folder = "gdm"
 gnome_folder = "gnome-shell"
 temp_gnome_folder = f"{temp_folder}/{gnome_folder}"
 tweaks_folder = "tweaks"

scripts/gdm.py

@@ -34,7 +34,7 @@ class GlobalTheme:
         self.theme_folder = theme_folder
         self.destination_folder = destination_folder
         self.destination_file = destination_file
-        self.temp_folder = os.path.join(temp_folder, "gdm")
+        self.temp_folder = temp_folder
 
         self.backup_file = f"{self.destination_file}.backup"
         self.backup_trigger = "\n/* Marble theme */\n"  # trigger to check if theme is installed

scripts/utils/is_photo.py

@@ -0,0 +1,21 @@
+image_extensions = [
+        'jpg', 'jpeg', 'png', 'gif', 'bmp',
+        'webp', 'tiff', 'tif', 'svg', 'heic', 'heif'
+    ]
+
+def is_photo(extension: str):
+    """
+    Check if extension is supported photo format
+    """
+
+    return extension.lower() in image_extensions
+
+class NotSupportedPhotoExtension(Exception):
+    """
+    Exception for not supported photo extension
+    """
+
+    def __init__(self, extension):
+        self.message = (f"Photo extension {extension} is not supported. "
+                        f"Supported formats: {", ".join(image_extensions)}.")
+        super().__init__(self.message)

tweaks/gdm/tweak.py

@@ -0,0 +1,86 @@
+import os.path
+import shutil
+import subprocess
+from argparse import ArgumentParser
+from scripts import config
+from scripts.utils.is_photo import is_photo, NotSupportedPhotoExtension
+
+def define_arguments(parser: ArgumentParser):
+    gdm_args = parser.add_argument_group("GDM tweaks")
+    gdm_args.add_argument("--gdm-image", type=str, nargs="?", help="Set GDM background image")
+    gdm_args.add_argument("--gdm-blur", type=int, nargs="?", help="Blur GDM background image (px)")
+    gdm_args.add_argument("--gdm-darken", type=int, choices=range(0, 100), help="Darken GDM background image (%)", metavar="(0 - 100)")
+    gdm_args.add_argument("--gdm-lighten",  type=int, choices=range(0, 100), help="Lighten GDM background image", metavar="(0 - 100)")
+
+
+def apply_tweak(args, theme, colors):
+    if args.gdm_image:
+        gdm_image = GDMImage(args.gdm_image, config.temp_folder, args.gdm_blur)
+
+        destination_dir = os.path.join(config.temp_folder, config.gdm_folder, config.raw_theme_folder)
+        os.makedirs(destination_dir, exist_ok=True)
+
+        gdm_image.copy_image(destination_dir)
+
+        theme += f"""
+            .login-dialog {{
+                background-image: url("{gdm_image.image_name}");
+                background-size: cover;
+                {f"box-shadow: inset 0 0 0 9999px rgba(0, 0, 0, {args.gdm_darken/100});" if args.gdm_darken else ""}
+                {f"box-shadow: inset 0 0 0 9999px rgba(255, 255, 255, {args.gdm_lighten/100});" if args.gdm_lighten else ""}
+            }}
+        """
+
+
+class GDMImage:
+    """
+    Class to apply effects to GDM background image
+    """
+
+    image_name: str
+
+    def __init__(self, path: str, temp_folder: str, blur: int = None):
+        self.path = path
+
+        extension = path.split(".")[-1]
+        if not is_photo(extension):
+            raise NotSupportedPhotoExtension(extension)
+
+        self.image_name = f"gdm-image.{extension}"
+        self.destination_dir = temp_folder
+        self.destination_file = os.path.join(self.destination_dir, self.image_name)
+
+        if not os.path.exists(self.destination_file):
+            self._create_file()
+            self._magick_tweaks(blur)
+
+    def copy_image(self, destination: str):
+        dest_path = os.path.join(destination, self.image_name)
+        shutil.copyfile(self.destination_file, dest_path)
+
+    def _create_file(self):
+        os.makedirs(self.destination_dir, exist_ok=True)
+        shutil.copyfile(self.path, self.destination_file)
+
+    def _magick_tweaks(self, blur: int = None):
+        if not shutil.which("magick"):
+            print("Warning: ImageMagick not found. Image effects will be skipped.")
+            return
+
+        file = self.destination_file
+
+        modified = False
+        command = ["magick", file]
+
+        if blur:
+            command.extend(["-blur", f"0x{blur}"])
+            modified = True
+
+        if modified:
+            print("Applying image filters... This may take a while.")
+            output_file = file
+            command.append(output_file)
+            try:
+                subprocess.run(command, check=True)
+            except subprocess.CalledProcessError:
+                print(f"Error: Failed to apply image effects to {file}")