Add 'usedpiscale' boolean (true by default) to love.window.setMode's settings table and love.conf's t.window table. Add love.window.getNativeDPIScale.

When usedpiscale=false, love will no longer automatically scale coordinates by the screen's DPI scale factor (so all coordinates will be in pixels), even when highdpi=true. love.window.getDPIScale will return 1, love.graphics.newCanvas will default to a dpi scale of 1 instead of the screen's dpi scale, etc.

love.window.getNativeDPIScale() will return the screen's DPI scale as reported by the OS no matter what usedpiscale is set to.

src/modules/window/sdl/Window.cpp

@@ -593,6 +593,7 @@ void Window::updateSettings(const WindowSettings &newsettings, bool updateGraphi
 	getPosition(settings.x, settings.y, settings.display);
 
 	settings.highdpi = (wflags & SDL_WINDOW_ALLOW_HIGHDPI) != 0;
+	settings.usedpiscale = newsettings.usedpiscale;
 
 	// Only minimize on focus loss if the window is in exclusive-fullscreen mode
 	if (settings.fullscreen && settings.fstype == FULLSCREEN_EXCLUSIVE)
@@ -1114,6 +1115,11 @@ void Window::DPIToWindowCoords(double *x, double *y) const
 }
 
 double Window::getDPIScale() const
+{
+	return settings.usedpiscale ? getNativeDPIScale() : 1.0;
+}
+
+double Window::getNativeDPIScale() const
 {
 #ifdef LOVE_ANDROID
 	return love::android::getScreenScale();

src/modules/window/sdl/Window.h

@@ -111,6 +111,7 @@ public:
 	void DPIToWindowCoords(double *x, double *y) const override;
 
 	double getDPIScale() const override;
+	double getNativeDPIScale() const override;
 
 	double toPixels(double x) const override;
 	void toPixels(double wx, double wy, double &px, double &py) const override;