Fix creation of loaders.cache on win32

Author: RedFantom

README.md

@@ -79,6 +79,7 @@ gttk = GTTK(window)
 style = ttk.Style()
 style.theme_use("gttk")
 print(gttk.get_current_theme()) # Prints the active GTK theme
+gttk.set_gtk_theme("Yaru") # Sets GTK theme, provided by developer
 ttk.Button(window, text="Destroy", command=window.destroy).pack()
 
 window.mainloop()
@@ -93,30 +94,6 @@ sys.path = sys.path[2:]
 import gttk
 ```
 
-## Applying themes
-Themes are applied in the standard GTK+-2.0 manner: By reading a 
-resource file. On **Linux**, the GTK libraries that are installed will point
-`gttk` in the direction of the globally enabled GTK theme. Currently,
-no method for overriding this behaviour is available.
-
-On **Windows**, the behaviour is a little different. GTK will look for 
-for the configuration files that point it towards the theme to be loaded
-in the files reported by
-```python
-GTTK.get_default_files()
-```
-and themes should be placed in the folder
-```python
-GTTK.get_themes_directory()
-```
-
-A method for reliably loading user themes is being researched, but for
-now this is the way to go. A `gtkrc` file may for example simply be
-```gtkrc
-gtk-theme-name = "Yaru"
-```
-where `some_path_here/share/themes/Yaru` is a valid GTK theme folder.
-
 ## Screenshots
 `gttk` should work with any GTK theme you can throw at it, but below
 are the themes Yaru and Adwaita as examples.

gttk/__init__.py

@@ -51,16 +51,20 @@ def __init__(self, window: tk.Tk, theme: Optional[str] = None, theme_dir_prefix:
         # Create loaders.cache on win32 platforms to find pixbuf loaders properly
         if "win" in sys.platform:
             target = os.path.join(temp_dir, "loaders.cache")
-            with open(os.path.join(folder, "loaders.cache")) as fi, open(target, "w") as fo:
+            source = os.path.join(folder, "lib", "gdk-pixbuf-2.0", "2.10.0", "loaders.cache")
+            with open(os.path.join(source)) as fi, open(target, "w") as fo:
                 cache = fi.read()
-                abspath = (os.path.join(folder, "lib", "gdk-pixbuf-2.0", "2.10.0", "loaders") + "\\")\
-                    .replace("\\", "\\\\")  # loaders.cache uses double \ everywhere
-                cache_w_abspaths = cache.replace("\\\\lib", abspath)
+                # loaders.cache uses double \ everywhere
+                abspath = (os.path.join(folder, "lib", ) + "\\").replace("\\", "\\\\")
+                cache_w_abspaths = cache.replace("lib\\\\", abspath)
                 fo.write(cache_w_abspaths)
             # Set GDK_PIXBUF_MODULE_FILE to the path of the new cache file
             # GDK_PIXBUF_MODULEDIR does not do anything for plain GDK!
             os.environ["GDK_PIXBUF_MODULE_FILE"] = target
 
+            # Set GTK_EXE_PREFIX on win32 to ensure theme engine loading
+            os.environ["GTK_EXE_PREFIX"] = folder
+
         with chdir(folder):
             # Evaluate pkgIndex.tcl, Tcl does not handle \ as a pathsep, so with /
             self.tk.eval("set dir {0}; source {0}/pkgIndex.tcl".format(folder.replace("\\", "/")))

setup.py

@@ -159,7 +159,7 @@ def copy_to_target(self, target: str):
     specials={
         "libpixmap.dll": "/lib/gtk-2.0/2.10.0/engines/", 
         "libwimp.dll": "/lib/gtk-2.0/2.10.0/engines/",
-        "loaders.cache": "/"}  # loaders.cache is used to specify abspaths to the loaders
+        "loaders.cache": "/lib/gdk-pixbuf-2.0/2.10.0/"}  # loaders.cache is used to specify abspaths to the loaders
     specials.update({"libpixbufloader-{}.dll".format(fmt): "/lib/gdk-pixbuf-2.0/2.10.0/loaders/"
                      for fmt in ["ani", "bmp", "gif", "icns", "ico", "jpeg", "png", "pnm", "qtif", "svg", "tga", "tiff", "xbm", "xpm"]})
     DependencyWalker("libgttk.dll", specials=specials).copy_to_target("gttk")