Scale resolution to true values

Source/options.cpp

@@ -39,6 +39,7 @@
 #include "options.h"
 #include "qol/monhealthbar.h"
 #include "qol/xpbar.h"
+#include "utils/display.h"
 #include "utils/file_util.h"
 #include "utils/language.h"
 #include "utils/log.hpp"
@@ -677,6 +678,7 @@ void OptionEntryResolution::CheckResolutionsAreInitialized() const
 		return;
 
 	std::vector<Size> sizes;
+	float scaleFactor = GetDpiScalingFactor();
 
 	// Add resolutions
 #ifdef USE_SDL1
@@ -687,7 +689,9 @@ void OptionEntryResolution::CheckResolutionsAreInitialized() const
 			if (modes[i]->w < modes[i]->h) {
 				std::swap(modes[i]->w, modes[i]->h);
 			}
-			sizes.emplace_back(Size { modes[i]->w, modes[i]->h * scaleFactor });
+			sizes.emplace_back(Size {
+			    static_cast<int>(modes[i]->w * scaleFactor),
+			    static_cast<int>(modes[i]->h * scaleFactor) });
 		}
 	}
 #else
@@ -700,7 +704,9 @@ void OptionEntryResolution::CheckResolutionsAreInitialized() const
 		if (mode.w < mode.h) {
 			std::swap(mode.w, mode.h);
 		}
-		sizes.emplace_back(Size { mode.w, mode.h * scaleFactor });
+		sizes.emplace_back(Size {
+		    static_cast<int>(mode.w * scaleFactor),
+		    static_cast<int>(mode.h * scaleFactor) });
 	}
 #endif
 

Source/utils/display.cpp

@@ -110,8 +110,32 @@ Size GetPreferredWindowSize()
 	AdjustToScreenGeometry(windowSize);
 	return windowSize;
 }
+
 } // namespace
 
+float GetDpiScalingFactor()
+{
+#ifdef USE_SDL1
+	return 1.0F;
+#else
+	if (renderer == nullptr)
+		return 1.0F;
+
+	int renderWidth;
+	int renderHeight;
+	SDL_GetRendererOutputSize(renderer, &renderWidth, &renderHeight);
+
+	int windowWidth;
+	int windowHeight;
+	SDL_GetWindowSize(ghMainWnd, &windowWidth, &windowHeight);
+
+	float hfactor = static_cast<float>(renderWidth) / windowWidth;
+	float vhfactor = static_cast<float>(renderHeight) / windowHeight;
+
+	return std::min(hfactor, vhfactor);
+#endif
+}
+
 #ifdef USE_SDL1
 void SetVideoMode(int width, int height, int bpp, uint32_t flags)
 {

Source/utils/display.h

@@ -26,6 +26,8 @@ extern SDLPaletteUniquePtr Palette;
 extern SDL_Surface *PalSurface;
 extern unsigned int pal_surface_palette_version;
 
+float GetDpiScalingFactor();
+
 #ifdef USE_SDL1
 void SetVideoMode(int width, int height, int bpp, uint32_t flags);
 void SetVideoModeToPrimary(bool fullscreen, int width, int height);