fix ui flashing on reloading and fast scrollong

modules/shared_gradio_themes.py

@@ -69,3 +69,44 @@ def reload_gradio_theme(theme_name=None):
     # append additional values gradio_theme
     shared.gradio_theme.sd_webui_modal_lightbox_toolbar_opacity = shared.opts.sd_webui_modal_lightbox_toolbar_opacity
     shared.gradio_theme.sd_webui_modal_lightbox_icon_opacity = shared.opts.sd_webui_modal_lightbox_icon_opacity
+
+
+def resolve_var(name: str, gradio_theme=None, history=None):
+    """
+    Attempt to resolve a theme variable name to its value
+
+    Parameters:
+        name (str): The name of the theme variable
+            ie "background_fill_primary", "background_fill_primary_dark"
+            spaces and asterisk (*) prefix is removed from name before lookup
+        gradio_theme (gradio.themes.ThemeClass): The theme object to resolve the variable from
+            blank to use the webui default shared.gradio_theme
+        history (list): A list of previously resolved variables to prevent circular references
+            for regular use leave blank
+    Returns:
+        str: The resolved value
+
+    Error handling:
+        return either #000000 or #ffffff depending on initial name ending with "_dark"
+    """
+    try:
+        if history is None:
+            history = []
+        if gradio_theme is None:
+            gradio_theme = shared.gradio_theme
+
+        name = name.strip()
+        name = name[1:] if name.startswith("*") else name
+
+        if name in history:
+            raise ValueError(f'Circular references: name "{name}" in {history}')
+
+        if value := getattr(gradio_theme, name, None):
+            return resolve_var(value, gradio_theme, history + [name])
+        else:
+            return name
+
+    except Exception:
+        name = history[0] if history else name
+        errors.report(f'resolve_color({name})', exc_info=True)
+        return '#000000' if name.endswith("_dark") else '#ffffff'

modules/ui_gradio_extensions.py

@@ -41,6 +41,11 @@ def stylesheet(fn):
     if os.path.exists(user_css):
         head += stylesheet(user_css)
 
+    from modules.shared_gradio_themes import resolve_var
+    light = resolve_var('background_fill_primary')
+    dark = resolve_var('background_fill_primary_dark')
+    head += f'<style>html {{ background-color: {light}; }} @media (prefers-color-scheme: dark) {{ html {{background-color:  {dark}; }} }}</style>'
+
     return head