Automatically set window scaling based on display pixel density (#21907)

Co-authored-by: Aaron van Geffen <aaron@aaronweb.net>

distribution/changelog.txt

@@ -6,6 +6,7 @@
 - Feature: [#22213] [Plugin] Allow plugins to focus on textboxes in custom windows.
 - Feature: [#22301] Loading save games or scenarios now indicates loading progress.
 - Feature: [OpenMusic#54] Added Progressive ride music style (feat. Approaching Nirvana).
+- Change: [#21494] Display pixel density is now taken into account for the initial window scale setting.
 - Change: [#22230] The plugin/script engine is now initialised off the main thread.
 - Change: [#22251] Hide author info in the scenery window unless debug tools are active.
 - Change: [#22309] The scenario editor now supports loading landscapes from .sea save files.

src/openrct2-ui/UiContext.cpp

@@ -732,6 +732,24 @@ private:
         LOG_VERBOSE("SDL2 version: %d.%d.%d", version.major, version.minor, version.patch);
     }
 
+    void InferDisplayDPI()
+    {
+        auto& config = Config::Get().general;
+        if (!config.InferDisplayDPI)
+            return;
+
+        int wWidth, wHeight;
+        SDL_GetWindowSize(_window, &wWidth, &wHeight);
+
+        auto renderer = SDL_GetRenderer(_window);
+        int rWidth, rHeight;
+        if (SDL_GetRendererOutputSize(renderer, &rWidth, &rHeight) == 0)
+            config.WindowScale = rWidth / wWidth;
+
+        config.InferDisplayDPI = false;
+        Config::Save();
+    }
+
     void CreateWindow(const ScreenCoordsXY& windowPos)
     {
         // Get saved window size
@@ -763,6 +781,7 @@ private:
 
         // Initialise the surface, palette and draw buffer
         DrawingEngineInit();
+        InferDisplayDPI();
         OnResize(width, height);
 
         UpdateFullscreenResolutions();

src/openrct2/config/Config.cpp

@@ -213,6 +213,7 @@ namespace OpenRCT2::Config
             model->DisableLightningEffect = reader->GetBoolean("disable_lightning_effect", false);
             model->SteamOverlayPause = reader->GetBoolean("steam_overlay_pause", true);
             model->WindowScale = reader->GetFloat("window_scale", Platform::GetDefaultScale());
+            model->InferDisplayDPI = reader->GetBoolean("infer_display_dpi", true);
             model->ShowFPS = reader->GetBoolean("show_fps", false);
 #ifdef _DEBUG
             // Always have multi-threading disabled in debug builds, this makes things slower.
@@ -303,6 +304,7 @@ namespace OpenRCT2::Config
         writer->WriteBoolean("disable_lightning_effect", model->DisableLightningEffect);
         writer->WriteBoolean("steam_overlay_pause", model->SteamOverlayPause);
         writer->WriteFloat("window_scale", model->WindowScale);
+        writer->WriteBoolean("infer_display_dpi", model->InferDisplayDPI);
         writer->WriteBoolean("show_fps", model->ShowFPS);
         writer->WriteBoolean("multithreading", model->MultiThreading);
         writer->WriteBoolean("trap_cursor", model->TrapCursor);

src/openrct2/config/Config.h

@@ -36,6 +36,7 @@ namespace OpenRCT2::Config
         int32_t FullscreenWidth;
         int32_t FullscreenHeight;
         float WindowScale;
+        bool InferDisplayDPI;
         ::DrawingEngine DrawingEngine;
         bool UncapFPS;
         bool UseVSync;