Really properly be per-monitor DPI aware

This is so hard...

src/frontend/main.h

@@ -1,28 +1,30 @@
-// Copyright 2019 threeSD Project
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include <memory>
-#include <QDialog>
-#include "core/importer.h"
-
-namespace Ui {
-class MainDialog;
-}
-
-class MainDialog : public QDialog {
-    Q_OBJECT
-
-public:
-    explicit MainDialog(QWidget* parent = nullptr);
-    ~MainDialog() override;
-
-private:
-    void LoadPresetConfig();
-    void LaunchImportDialog();
-
-    std::vector<Core::Config> preset_config_list;
-    std::unique_ptr<Ui::MainDialog> ui;
-};
+// Copyright 2019 threeSD Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include "core/importer.h"
+#include "frontend/helpers/dpi_aware_dialog.h"
+
+namespace Ui {
+class MainDialog;
+}
+
+class MainDialog final : public DPIAwareDialog {
+    Q_OBJECT
+
+public:
+    explicit MainDialog(QWidget* parent = nullptr);
+    ~MainDialog() override;
+
+private:
+    void SetContentSizes(int previous_width, int previous_height) override;
+
+    void LoadPresetConfig();
+    void LaunchImportDialog();
+
+    std::vector<Core::Config> preset_config_list;
+    std::unique_ptr<Ui::MainDialog> ui;
+};