Use retina icons for the main toolbar if first opened on a retina display

aegisub/src/osx_utils.mm

@@ -61,3 +61,8 @@ void SetPlaceholderText(wxWindow *window, wxString const& placeholder) {
         cell.placeholderString = wxCFStringRef(placeholder).AsNSString();
     }
 }
+
+double GetScaleFactor(wxWindow *window) {
+    NSWindow *nsWindow = [window->GetHandle() window];
+    return [nsWindow respondsToSelector:@selector(backingScaleFactor)] ? nsWindow.backingScaleFactor : 1.0;
+}

aegisub/src/toolbar.cpp

@@ -26,6 +26,7 @@
 #include "include/aegisub/hotkey.h"
 #include "libresrc/libresrc.h"
 #include "options.h"
+#include "utils.h"
 
 #include <libaegisub/hotkey.h>
 #include <libaegisub/json.h>
@@ -186,7 +187,7 @@ namespace {
 		, icon_size(OPT_GET("App/Toolbar Icon Size")->GetInt())
 		, icon_size_slot(OPT_SUB("App/Toolbar Icon Size", &Toolbar::OnIconSizeChange, this))
 #else
-		, icon_size(32)
+		, icon_size(32 * GetScaleFactor(parent))
 #endif
 		, hotkeys_changed_slot(hotkey::inst->AddHotkeyChangeListener(&Toolbar::RegenerateToolbar, this))
 		{

aegisub/src/utils.cpp

@@ -271,6 +271,7 @@ size_t MaxLineLength(std::string const& text, bool ignore_whitespace) {
 #ifndef __WXOSX_COCOA__
 void AddFullScreenButton(wxWindow *) { }
 void SetFloatOnParent(wxWindow *) { }
+double GetScaleFactor(wxWindow *) { return 1; }
 #endif
 
 wxString FontFace(std::string opt_prefix) {

aegisub/src/utils.h

@@ -49,6 +49,7 @@
 
 class wxMouseEvent;
 class wxWindow;
+namespace cmd { class Command; }
 
 wxString PrettySize(int bytes);
 
@@ -77,6 +78,8 @@ void SetFloatOnParent(wxWindow *window);
 
 void SetPlaceholderText(wxWindow *window, wxString const& placeholder);
 
+double GetScaleFactor(wxWindow *window);
+
 /// Forward a mouse wheel event to the window under the mouse if needed
 /// @param source The initial target of the wheel event
 /// @param evt The event