Bug 1745589 - Ensure we also draw headerbar parent if the headerbar has no background. r=stransky

Even if it has a radius. This can happen in older ElementaryOS themes...

Differential Revision: https://phabricator.services.mozilla.com/D133588

widget/gtk/WidgetStyleCache.cpp

@@ -10,6 +10,7 @@
 #include "gtkdrawing.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/PodOperations.h"
+#include "mozilla/ScopeExit.h"
 #include "nsDebug.h"
 #include "nsPrintfCString.h"
 #include "nsString.h"
@@ -26,6 +27,8 @@ enum class CSDStyle {
   Normal,
 };
 
+static bool gHeaderBarShouldDrawContainer = false;
+static bool gMaximizedHeaderBarShouldDrawContainer = false;
 static CSDStyle gCSDStyle = CSDStyle::Unknown;
 static GtkWidget* sWidgetStorage[MOZ_GTK_WIDGET_NODE_COUNT];
 static GtkStyleContext* sStyleStorage[MOZ_GTK_WIDGET_NODE_COUNT];
@@ -440,6 +443,21 @@ static GtkWidget* CreateNotebookWidget() {
   return widget;
 }
 
+static bool HasBackground(GtkStyleContext* aStyle) {
+  GdkRGBA gdkColor;
+  gtk_style_context_get_background_color(aStyle, GTK_STATE_FLAG_NORMAL,
+                                         &gdkColor);
+  if (gdkColor.alpha != 0.0) {
+    return true;
+  }
+
+  GValue value = G_VALUE_INIT;
+  gtk_style_context_get_property(aStyle, "background-image",
+                                 GTK_STATE_FLAG_NORMAL, &value);
+  auto cleanup = mozilla::MakeScopeExit([&] { g_value_unset(&value); });
+  return g_value_get_boxed(&value);
+}
+
 static void CreateHeaderBarWidget(WidgetNodeType aAppearance) {
   GtkWidget* window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
   GtkStyleContext* windowStyle = gtk_widget_get_style_context(window);
@@ -489,7 +507,27 @@ static void CreateHeaderBarWidget(WidgetNodeType aAppearance) {
   }
 
   gtk_container_add(GTK_CONTAINER(window), fixed);
-  gtk_container_add(GTK_CONTAINER(fixed), sWidgetStorage[aAppearance]);
+  gtk_container_add(GTK_CONTAINER(fixed), headerBar);
+
+  gtk_style_context_invalidate(headerBarStyle);
+  gtk_style_context_invalidate(fixedStyle);
+
+  // Some themes like Elementary's style the container of the headerbar rather
+  // than the header bar itself.
+  bool& shouldDrawContainer = aAppearance == MOZ_GTK_HEADER_BAR
+                                  ? gHeaderBarShouldDrawContainer
+                                  : gMaximizedHeaderBarShouldDrawContainer;
+  shouldDrawContainer = [&] {
+    const bool headerBarHasBackground = HasBackground(headerBarStyle);
+    if (headerBarHasBackground && GetBorderRadius(headerBarStyle)) {
+      return false;
+    }
+    if (HasBackground(fixedStyle) &&
+        (GetBorderRadius(fixedStyle) || !headerBarHasBackground)) {
+      return true;
+    }
+    return false;
+  }();
 }
 
 #define ICON_SCALE_VARIANTS 2
@@ -554,7 +592,7 @@ static void CreateHeaderBarButton(GtkWidget* aParentWidget,
 
   // We bypass GetWidget() here because we create all titlebar
   // buttons at once when a first one is requested.
-  NS_ASSERTION(sWidgetStorage[aAppearance] == nullptr,
+  NS_ASSERTION(!sWidgetStorage[aAppearance],
                "Titlebar button is already created!");
   sWidgetStorage[aAppearance] = widget;
 
@@ -754,6 +792,8 @@ static GtkWidget* CreateWidget(WidgetNodeType aAppearance) {
       return CreateComboBoxEntryArrowWidget();
     case MOZ_GTK_HEADERBAR_WINDOW:
     case MOZ_GTK_HEADERBAR_WINDOW_MAXIMIZED:
+    case MOZ_GTK_HEADERBAR_FIXED:
+    case MOZ_GTK_HEADERBAR_FIXED_MAXIMIZED:
     case MOZ_GTK_HEADER_BAR:
     case MOZ_GTK_HEADER_BAR_MAXIMIZED:
     case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
@@ -1461,6 +1501,15 @@ void StyleContextSetScale(GtkStyleContext* style, gint aScaleFactor) {
   }
 }
 
+bool HeaderBarShouldDrawContainer(WidgetNodeType aNodeType) {
+  MOZ_ASSERT(aNodeType == MOZ_GTK_HEADER_BAR ||
+             aNodeType == MOZ_GTK_HEADER_BAR_MAXIMIZED);
+  mozilla::Unused << GetWidget(aNodeType);
+  return aNodeType == MOZ_GTK_HEADER_BAR
+             ? gHeaderBarShouldDrawContainer
+             : gMaximizedHeaderBarShouldDrawContainer;
+}
+
 gint GetBorderRadius(GtkStyleContext* aStyle) {
   GValue value = G_VALUE_INIT;
   // NOTE(emilio): In an ideal world, we'd query the two longhands

widget/gtk/WidgetStyleCache.h

@@ -58,4 +58,6 @@ void StyleContextSetScale(GtkStyleContext* style, gint aScaleFactor);
 
 gint GetBorderRadius(GtkStyleContext* aStyle);
 
+bool HeaderBarShouldDrawContainer(WidgetNodeType);
+
 #endif  // WidgetStyleCache_h

widget/gtk/gtk3drawing.cpp

@@ -2177,15 +2177,12 @@ static gint moz_gtk_header_bar_paint(WidgetNodeType widgetType, cairo_t* cr,
 
   // Some themes like Elementary's style the container of the headerbar rather
   // than the header bar itself.
-  if (!GetBorderRadius(style)) {
+  if (HeaderBarShouldDrawContainer(widgetType)) {
     auto containerType = widgetType == MOZ_GTK_HEADER_BAR
                              ? MOZ_GTK_HEADERBAR_FIXED
                              : MOZ_GTK_HEADERBAR_FIXED_MAXIMIZED;
-    GtkStyleContext* containerStyle = GetStyleContext(
+    style = GetStyleContext(
         containerType, state->scale, GTK_TEXT_DIR_NONE, state_flags);
-    if (GetBorderRadius(containerStyle)) {
-      style = containerStyle;
-    }
   }
 
 // Some themes (Adwaita for instance) draws bold dark line at

widget/gtk/nsLookAndFeel.cpp

@@ -1549,7 +1549,10 @@ void nsLookAndFeel::PerThemeData::Init() {
     g_object_unref(accelStyle);
   }
 
-  style = GetStyleContext(MOZ_GTK_HEADER_BAR);
+  const auto effectiveHeaderBarStyle =
+      HeaderBarShouldDrawContainer(MOZ_GTK_HEADER_BAR) ? MOZ_GTK_HEADERBAR_FIXED
+                                                       : MOZ_GTK_HEADER_BAR;
+  style = GetStyleContext(effectiveHeaderBarStyle);
   {
     gtk_style_context_get_color(style, GTK_STATE_FLAG_NORMAL, &color);
     mTitlebarText = GDK_RGBA_TO_NS_RGBA(color);
@@ -1559,15 +1562,7 @@ void nsLookAndFeel::PerThemeData::Init() {
     mTitlebarInactiveText = GDK_RGBA_TO_NS_RGBA(color);
     mTitlebarInactiveBackground =
         GetBackgroundColor(style, mTitlebarText, GTK_STATE_FLAG_BACKDROP);
-    mTitlebarRadius = 0;
-    if (!IsSolidCSDStyleUsed()) {
-      mTitlebarRadius = GetBorderRadius(style);
-      if (!mTitlebarRadius) {
-        // Some themes like ElementaryOS set the radius on the headerbar parent.
-        style = GetStyleContext(MOZ_GTK_HEADERBAR_FIXED);
-        mTitlebarRadius = GetBorderRadius(style);
-      }
-    }
+    mTitlebarRadius = IsSolidCSDStyleUsed() ? 0 : GetBorderRadius(style);
   }
 
   style = GetStyleContext(MOZ_GTK_MENUPOPUP);