From ce8eb4cda242963af51df39887021c5ec7207046 Mon Sep 17 00:00:00 2001
From: "Matthew J. Milner" <matterhorn103@proton.me>
Date: Thu, 18 Jan 2024 15:28:22 +0100
Subject: [PATCH] Add code to check for current palette being a dark theme

Signed-off-by: Matthew J. Milner <matterhorn103@proton.me>
---
 avogadro/qtgui/toolplugin.cpp | 11 +++++++++++
 avogadro/qtgui/toolplugin.h   |  3 +++
 2 files changed, 14 insertions(+)

diff --git a/avogadro/qtgui/toolplugin.cpp b/avogadro/qtgui/toolplugin.cpp
index 249c2a2638..dfce653258 100644
--- a/avogadro/qtgui/toolplugin.cpp
+++ b/avogadro/qtgui/toolplugin.cpp
@@ -4,6 +4,7 @@
 ******************************************************************************/
 
 #include "toolplugin.h"
+#include <QtGui/QPalette>
 
 namespace Avogadro::QtGui {
 
@@ -58,4 +59,14 @@ bool ToolPlugin::handleCommand(const QString& command,
 
 ToolPluginFactory::~ToolPluginFactory() {}
 
+// Method suggested by Qt to determine if theme is dark pre Qt6.5
+static bool shouldApplyDarkFrame()
+{
+  const QPalette defaultPalette;
+    return defaultPalette.color(QPalette::WindowText).lightness()
+      > defaultPalette.color(QPalette::Window).lightness();
+}
+
+bool ToolPlugin::darkTheme = shouldApplyDarkFrame();
+
 } // namespace Avogadro::QtGui
diff --git a/avogadro/qtgui/toolplugin.h b/avogadro/qtgui/toolplugin.h
index 0c72b0f3bb..36c344f877 100644
--- a/avogadro/qtgui/toolplugin.h
+++ b/avogadro/qtgui/toolplugin.h
@@ -40,6 +40,9 @@ class AVOGADROQTGUI_EXPORT ToolPlugin : public QObject
 {
   Q_OBJECT
 
+private:
+  static bool darkTheme;
+
 public:
   explicit ToolPlugin(QObject* parent = nullptr);
   ~ToolPlugin() override;