Merge pull request #600 from Sjoerd1993/Set-headerbar-CSS-on-style-ch…

…ange

Set headerbar css on style change

src/styles.py

@@ -194,6 +194,19 @@ def _on_style_change(self, override: bool = False) -> None:
                 figure_settings.bind_property(prop, canvas, prop, 1 | 2)
         data.bind_property("items", canvas, "items", 2)
         window = self.props.application.get_window()
+        headerbar = window.get_content_headerbar()
+        headerbar.provider = Gtk.CssProvider()
+
+        # Set headerbar color and contrast
+        bg_color = self._selected_style_params["figure.facecolor"]
+        contrast = utilities.get_luminance(bg_color)
+        color = "@dark_5" if contrast > 150 else "@light_1"
+        css = f"headerbar {{ background-color: {bg_color}; color: {color}; }}"
+        context = headerbar.get_style_context()
+        headerbar.provider.load_from_data(css.encode())
+        context.add_provider(headerbar.provider,
+                             Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION)
+
         window.set_canvas(canvas)
         window.get_cut_button().bind_property(
             "sensitive", canvas, "highlight_enabled", 2,

src/utilities.py

@@ -18,6 +18,14 @@ def hex_to_rgba(hex_str):
     return rgba
 
 
+def get_luminance(hex_color):
+    color = hex_color[1:]
+    hex_red = int(color[0:2], base=16)
+    hex_green = int(color[2:4], base=16)
+    hex_blue = int(color[4:6], base=16)
+    return hex_red * 0.2126 + hex_green * 0.7152 + hex_blue * 0.0722
+
+
 def sig_fig_round(number, digits):
     """Round a number to the specified number of significant digits."""
     try:

src/window.vala

@@ -60,6 +60,9 @@ namespace Graphs {
         [GtkChild]
         private unowned Adw.ToastOverlay toast_overlay { get; }
 
+        [GtkChild]
+        public unowned Adw.HeaderBar content_headerbar { get; }
+
         public int mode {
             set {
                 this.pan_button.set_active (value == 0);