[studio] Add handling for DPI changes

src/olympic/studio/applib/src/studioui.cpp

@@ -121,25 +121,7 @@ using StudioConfig = StudioConfigV2;
 StudioUI::StudioUI(turbine::Context &tctx, ox::StringParam projectDataDir) noexcept:
 		m_sctx{*this, tctx},
 		m_projectDataDir{std::move(projectDataDir)} {
-	{
-		auto const scale = turbine::isWayland() || ox::defines::OS == ox::OS::Darwin ?
-			1.f : turbine::scale(m_tctx);
-		ImFontConfig fontCfg;
-		fontCfg.FontDataOwnedByAtlas = false;
-		auto const &io = ImGui::GetIO();
-		auto const font = files::RobotoMedium_ttf();
-		// const_cast is needed because this data is definitely const,
-		// but AddFontFromMemoryTTF requires a mutable buffer.
-		// However, setting fontCfg.FontDataOwnedByAtlas ensures
-		// that it will still be treated as const.
-		// ImGui documentation recognizes that this is a bad design,
-		// and hopefully it will change at some point.
-		io.Fonts->AddFontFromMemoryTTF(
-			const_cast<uint8_t*>(font.data()),
-			static_cast<int>(font.size()),
-			13 * scale,
-			&fontCfg);
-	}
+	loadFont();
 	auto &kctx = keelCtx(m_tctx);
 	kctx.converters.emplace_back(keel::Converter::make<convertStudioConfigV1ToStudioConfigV2>());
 	oxLogError(headerizeConfigFile<StudioConfigV1>(kctx));
@@ -206,6 +188,7 @@ void StudioUI::draw() noexcept {
 	if (turbine::isWayland() || ox::defines::OS == ox::OS::Darwin) {
 		ig::setDpiScale(1.f);
 	} else {
+		loadFont();
 		ig::setDpiScale(ImGui::GetWindowDpiScale());
 	}
 	glutils::clearScreen();
@@ -240,6 +223,29 @@ void StudioUI::draw() noexcept {
 	procFileMoves();
 }
 
+void StudioUI::loadFont() noexcept {
+	auto const scale = turbine::isWayland() || ox::defines::OS == ox::OS::Darwin ?
+		1.f : turbine::scale(m_tctx);
+	if (m_fontScale != scale) {
+		m_fontScale = scale;
+		ImFontConfig fontCfg;
+		fontCfg.FontDataOwnedByAtlas = false;
+		auto const &io = ImGui::GetIO();
+		auto const font = files::RobotoMedium_ttf();
+		// const_cast is needed because this data is definitely const,
+		// but AddFontFromMemoryTTF requires a mutable buffer.
+		// However, setting fontCfg.FontDataOwnedByAtlas ensures
+		// that it will still be treated as const.
+		// ImGui documentation recognizes that this is a bad design,
+		// and hopefully it will change at some point.
+		io.Fonts->AddFontFromMemoryTTF(
+			const_cast<uint8_t*>(font.data()),
+			static_cast<int>(font.size()),
+			13 * scale,
+			&fontCfg);
+	}
+}
+
 bool StudioUI::handleShutdown() noexcept {
 	auto const out = ox::all_of(m_editors.begin(), m_editors.end(), [](ox::UPtr<BaseEditor> const &e) {
 		return !e->unsavedChanges();

src/olympic/studio/applib/src/studioui.hpp

@@ -84,6 +84,7 @@ class StudioUI final: public ox::SignalHandler {
 			ox::String args;
 		};
 		ox::Optional<NavAction> m_navAction;
+		float m_fontScale{};
 
 	public:
 		explicit StudioUI(turbine::Context &tctx, ox::StringParam projectDataDir) noexcept;
@@ -105,6 +106,8 @@ class StudioUI final: public ox::SignalHandler {
 		void draw() noexcept;
 
 	private:
+		void loadFont() noexcept;
+
 		void drawMenu() noexcept;
 
 		void drawTabBar() noexcept;