When applying video defaults, set the aspect ratio to the monitor's. In windowed mode, automatically adjust the window width to make pixels square.

stepmania/src/ScreenOptionsMasterPrefs.cpp

@@ -556,7 +556,7 @@ static void RefreshRate( int &sel, bool ToSel, const ConfOption *pConfOption )
 
 static void DisplayAspectRatio( int &sel, bool ToSel, const ConfOption *pConfOption )
 {
-	const float mapping[] = { 3/4.f,1,4/3.0f,16/10.0f,16/9.f, 8/3.f };
+	const float mapping[] = { 3/4.f, 1, 4/3.0f, 16/10.0f, 16/9.f, 8/3.f };
 	MoveMap( sel, pConfOption, ToSel, mapping, ARRAYLEN(mapping) );
 }
 
@@ -701,7 +701,7 @@ static void InitializeConfOptions()
 	ADD( ConfOption( "DisplayResolution",		DisplayResolutionM, DisplayResolutionChoices ) );
 	g_ConfOptions.back().m_iEffects = OPT_APPLY_GRAPHICS | OPT_APPLY_ASPECT_RATIO;
 	ADD( ConfOption( "DisplayAspectRatio",		DisplayAspectRatio,	"|3:4","|1:1","|4:3","|16:10","|16:9","|8:3" ) );
-	g_ConfOptions.back().m_iEffects = OPT_APPLY_ASPECT_RATIO;
+	g_ConfOptions.back().m_iEffects = OPT_APPLY_GRAPHICS | OPT_APPLY_ASPECT_RATIO;	// need OPT_APPLY_GRAPHICS because if windowed the width may change to make square pixels
 	ADD( ConfOption( "WideScreen16_10",		WideScreen16_10,	"Off", "On" ) );
 	g_ConfOptions.back().m_sPrefName = "DisplayAspectRatio";
 	g_ConfOptions.back().m_iEffects = OPT_APPLY_ASPECT_RATIO;

stepmania/src/StepMania.cpp

@@ -84,21 +84,34 @@ static Preference<bool> g_bAllowMultipleInstances( "AllowMultipleInstances", fal
 
 void StepMania::GetPreferredVideoModeParams( VideoModeParams &paramsOut )
 {
+	/*
+	 * We can't rely on there being full-screen video modes that give us square pixels 
+	 * at non-4:3 aspects.  The lowest non-4:3 resolution my new laptop with Radeon supports is 1280x720.  
+	 * In most cases, we'll using a 4:3 resolution when full-screen let the monitor stretch to the correct 
+	 * aspect.  When windowed (no monitor stretching), we will tweak the width so that we get square pixels.
+	 * -Chris
+	 */
+	int iWidth = PREFSMAN->m_iDisplayWidth;
+	if( PREFSMAN->m_bWindowed )
+	{
+		iWidth = PREFSMAN->m_iDisplayHeight * PREFSMAN->m_fDisplayAspectRatio;
+	}
+
 	paramsOut = VideoModeParams(
-			PREFSMAN->m_bWindowed,
+		PREFSMAN->m_bWindowed,
-			PREFSMAN->m_iDisplayWidth,
+		iWidth,
-			PREFSMAN->m_iDisplayHeight,
+		PREFSMAN->m_iDisplayHeight,
-			PREFSMAN->m_iDisplayColorDepth,
+		PREFSMAN->m_iDisplayColorDepth,
-			PREFSMAN->m_iRefreshRate,
+		PREFSMAN->m_iRefreshRate,
-			PREFSMAN->m_bVsync,
+		PREFSMAN->m_bVsync,
-			PREFSMAN->m_bInterlaced,
+		PREFSMAN->m_bInterlaced,
-			PREFSMAN->m_bSmoothLines,
+		PREFSMAN->m_bSmoothLines,
-			PREFSMAN->m_bTrilinearFiltering,
+		PREFSMAN->m_bTrilinearFiltering,
-			PREFSMAN->m_bAnisotropicFiltering,
+		PREFSMAN->m_bAnisotropicFiltering,
-			CommonMetrics::WINDOW_TITLE,
+		CommonMetrics::WINDOW_TITLE,
-			THEME->GetPathG("Common","window icon"),
+		THEME->GetPathG("Common","window icon"),
-			PREFSMAN->m_bPAL,
+		PREFSMAN->m_bPAL,
-			PREFSMAN->m_fDisplayAspectRatio
+		PREFSMAN->m_fDisplayAspectRatio
 	);
 }
 
@@ -131,11 +144,21 @@ static RString GetActualGraphicOptionsString()
 
 static void StoreActualGraphicOptions()
 {
-	// find out what we actually have
+	/* Store the settings that RageDisplay was actually able to use so that
+	 * we don't go through the process of auto-detecting a usable video mode
+	 * every time.
+	 */
 	const VideoModeParams &params = DISPLAY->GetActualVideoModeParams();
 	PREFSMAN->m_bWindowed		.Set( params.windowed );
-	PREFSMAN->m_iDisplayWidth	.Set( params.width );
+
-	PREFSMAN->m_iDisplayHeight	.Set( params.height );
+	/* If we're windowed, we may have tweaked the width based on the aspect ratio.  
+	 * Don't save this new value over the preferred value.
+	 */
+	if( !PREFSMAN->m_bWindowed )
+	{
+		PREFSMAN->m_iDisplayWidth	.Set( params.width );
+		PREFSMAN->m_iDisplayHeight	.Set( params.height );
+	}
 	PREFSMAN->m_iDisplayColorDepth	.Set( params.bpp );
 	if( PREFSMAN->m_iRefreshRate != REFRESH_DEFAULT )
 		PREFSMAN->m_iRefreshRate.Set( params.rate );
@@ -649,6 +672,7 @@ found_defaults:
 		PREFSMAN->m_iMovieColorDepth.Set( defaults.iMovieColor );
 		PREFSMAN->m_iMaxTextureResolution.Set( defaults.iTextureSize );
 		PREFSMAN->m_bSmoothLines.Set( defaults.bSmoothLines );
+		PREFSMAN->m_fDisplayAspectRatio.Set( HOOKS->GetDisplayAspectRatio() );
 
 		// Update last seen video card
 		PREFSMAN->m_sLastSeenVideoDriver.Set( GetVideoDriverName() );

stepmania/src/arch/ArchHooks/ArchHooks.h

@@ -113,6 +113,8 @@ public:
 	 */
 	virtual bool GoToURL( RString sUrl );
 
+	virtual float GetDisplayAspectRatio() = 0;
+
 private:
 	/* This are helpers for GetMicrosecondsSinceStart on systems with a timer
 	 * that may loop or move backwards. */

stepmania/src/arch/ArchHooks/ArchHooks_Win32.cpp

@@ -183,6 +183,16 @@ bool ArchHooks_Win32::GoToURL( RString sUrl )
 	return ::GotoURL( sUrl );
 }
 
+float ArchHooks_Win32::GetDisplayAspectRatio()
+{
+	DEVMODE dm;
+	ZERO( dm );
+	dm.dmSize = sizeof(dm);
+	BOOL bResult = EnumDisplaySettings( NULL, ENUM_REGISTRY_SETTINGS, &dm );
+	ASSERT( bResult );
+	return dm.dmPelsWidth / (float)dm.dmPelsHeight;
+}
+
 /*
  * (c) 2003-2004 Glenn Maynard, Chris Danford
  * All rights reserved.

stepmania/src/arch/ArchHooks/ArchHooks_Win32.h

@@ -22,6 +22,7 @@ public:
 	void SetupConcurrentRenderingThread();
 	
 	bool GoToURL( RString sUrl );
+	virtual float GetDisplayAspectRatio();
 };
 
 #ifdef ARCH_HOOKS