Enable RDStyle by default, add style selection in the settings dialog

qrenderdoc/Code/qrenderdoc.cpp

@@ -166,6 +166,26 @@ int main(int argc, char *argv[])
 
     config.SetupFormatting();
 
+    bool isDarkTheme = false;
+
+    {
+      float baseLum = getLuminance(application.palette().color(QPalette::Base));
+      float textLum = getLuminance(application.palette().color(QPalette::Text));
+
+      // if the base is dark than the text, then it's a light-on-dark theme (aka dark theme)
+      isDarkTheme = (baseLum < textLum);
+    }
+
+    bool styleSet = config.SetStyle();
+
+    // unrecognised style, or empty (none set), choose a default
+    if(!styleSet)
+    {
+      config.UIStyle = isDarkTheme ? lit("RDDark") : lit("RDLight");
+
+      config.SetStyle();
+    }
+
     Resources::Initialise();
 
     GUIInvoke::init();