Merge lp:~stellarium/stellarium/gz_viewportOffset into lp:stellarium

[gzotti]

Introducing the option to have a vertically offset screen center. Useful to have e.g. cylindrical views with straight landcape horizon in lower part of the screen.

Object tracking&centering brings those objects into visible screen center. Centering on coordinates puts those coordinates into the offset projection center now, this is intended.

I hope I have not overlooked something in the view geometry?

[Alexander Wolf (alexwolf)]

Current implementation has stepwise centering of the object when zooming. Can it be smooth zooming?

review: Needs Fixing

[gzotti (georg-zotti)]

Oops... yes, I must have a look into that!

[lp:~stellarium/stellarium/gz_viewportOffset]

7736. By gzotti on 2015-07-21

add a "galactic" projection mode for scripting.

7737. By gzotti on 2015-07-21

Smoothed zooming (keep centered object in center for offset view mode), and repaired offset adjusting for all view frame (mount) modes

[gzotti (georg-zotti)]

OK, zooming now runs smooth, and in all mount modes. Also made galactic mount mode reachable at least for scripting.

review: Needs Resubmitting

[Alexander Wolf (alexwolf)]

Zooming with movement is not exactly smooth. Please try simple use case for both versions (trunk and gz_viewportOffset): disable atmosphere and ground, select any object on screen near border and press "/" (zoom in). Movement is stepwize yet.

review: Needs Fixing

[gzotti (georg-zotti)]

Ouch. Again one of the keys/functions I never found in 7 years because they don't work on German keyboards. OK, after reconfiguring I can see what you mean. Practically object is immediately centered, right?

Are there any other ways of zooming/centering? I always only used the mouse or PgUp/Down.

review: Needs Information

[lp:~stellarium/stellarium/gz_viewportOffset]

7738. By gzotti on 2015-07-24

zoom+movement (default key "/") now also smoothened.

[gzotti (georg-zotti)]

OK, next try please? The selected object is now not immediately centered. I hope it was what you meant?

review: Needs Resubmitting

[Alexander Wolf (alexwolf)]

Apparently he is not broke a frequently used features now.

review: Approve

[Alexander Wolf (alexwolf)]

P.S. This feature introduced an issue in projection of the sky (artifacts at the bottom side of the screen).

[gzotti (georg-zotti)]

Well, yes, if you zoom out too far, some artifacts/limitations of any projection become apparent even stronger than without offsetting center. I see some disturbing faces or lines when zooming out in stereographic projection near zenith, and faces of the "sphere border", but the "solution" would simply include an fov limit adaptation, but I think it is better like that, and users can zoom in a bit if the weird faces really disturb.

=== modified file 'src/core/StelCore.cpp'
--- src/core/StelCore.cpp	2015-07-08 10:37:11 +0000
+++ src/core/StelCore.cpp	2015-07-24 14:57:31 +0000
@@ -86,6 +86,10 @@
 	const float viewportCenterX = conf->value("projection/viewport_center_x",0.5f*viewport_width).toFloat();
 	const float viewportCenterY = conf->value("projection/viewport_center_y",0.5f*viewport_height).toFloat();
 	currentProjectorParams.viewportCenter.set(viewportCenterX, viewportCenterY);
+	const float viewportCenterOffsetX = conf->value("projection/viewport_center_offset_x",0.f).toFloat();
+	const float viewportCenterOffsetY = conf->value("projection/viewport_center_offset_y",0.f).toFloat();
+	currentProjectorParams.viewportCenterOffset.set(viewportCenterOffsetX, viewportCenterOffsetY);
+
 	currentProjectorParams.viewportFovDiameter = conf->value("projection/viewport_fov_diameter", qMin(viewport_width,viewport_height)).toFloat();
 	currentProjectorParams.flipHorz = conf->value("projection/flip_horz",false).toBool();
 	currentProjectorParams.flipVert = conf->value("projection/flip_vert",false).toBool();
@@ -384,7 +388,7 @@
 {
 	// Maximize display when resized since it invalidates previous options anyway
 	currentProjectorParams.viewportXywh.set(x, y, width, height);
-	currentProjectorParams.viewportCenter.set(x+0.5*width, y+0.5*height);
+	currentProjectorParams.viewportCenter.set(x+(0.5+currentProjectorParams.viewportCenterOffset.v[0])*width, y+(0.5+currentProjectorParams.viewportCenterOffset.v[1])*height);
 	currentProjectorParams.viewportFovDiameter = qMin(width,height);
 }
 

=== modified file 'src/core/StelMovementMgr.cpp'
--- src/core/StelMovementMgr.cpp	2015-04-01 14:36:44 +0000
+++ src/core/StelMovementMgr.cpp	2015-07-24 14:57:31 +0000
@@ -1,6 +1,7 @@
 /*
  * Stellarium
  * Copyright (C) 2007 Fabien Chereau
+ * Copyright (C) 2015 Georg Zotti (offset view adaptations)
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -102,9 +103,7 @@
 	flagAutoZoomOutResetsDirection = conf->value("navigation/auto_zoom_out_resets_direction", true).toBool();
 	flagEnableMouseNavigation = conf->value("navigation/flag_enable_mouse_navigation",true).toBool();
 
-	minFov = 0.001389; // minimal FOV = 5"
-	// GZ: This value should be configurable! Zooming in too much is useless for archaeoastronomy.
-	minFov = conf->value("navigation/min_fov",minFov).toDouble();
+	minFov = conf->value("navigation/min_fov",0.001389).toDouble(); // default: minimal FOV = 5"
 	maxFov = 100.;
 	initFov = conf->value("navigation/init_fov",60.f).toFloat();
 	currentFov = initFov;
@@ -464,7 +463,7 @@
 }
 
 /*************************************************************************
- The selected objects changed, follow it it we were already following another one
+ The selected objects changed, follow it if we were already following another one
 *************************************************************************/
 void StelMovementMgr::selectedObjectChange(StelModule::StelModuleSelectAction)
 {
@@ -561,29 +560,24 @@
 		if (deltaAz<-0.2)
 			deltaAz = -0.2;
 	}
-	else
+	else if (deltaAz>0)
 	{
-		if (deltaAz>0)
-		{
-			deltaAz = (depl/30);
-			if (deltaAz>0.2)
-				deltaAz = 0.2;
-		}
+		deltaAz = (depl/30);
+		if (deltaAz>0.2)
+			deltaAz = 0.2;
 	}
+
 	if (deltaAlt<0)
 	{
 		deltaAlt = -depl/30;
 		if (deltaAlt<-0.2)
 			deltaAlt = -0.2;
 	}
-	else
+	else if (deltaAlt>0)
 	{
-		if (deltaAlt>0)
-		{
-			deltaAlt = depl/30;
-			if (deltaAlt>0.2)
-				deltaAlt = 0.2;
-		}
+		deltaAlt = depl/30;
+		if (deltaAlt>0.2)
+			deltaAlt = 0.2;
 	}
 
 	if (deltaFov<0)
@@ -592,14 +586,11 @@
 		if (deltaFov<-0.15*currentFov)
 			deltaFov = -0.15*currentFov;
 	}
-	else
+	else if (deltaFov>0)
 	{
-		if (deltaFov>0)
-		{
-			deltaFov = deplzoom*5;
-			if (deltaFov>20)
-				deltaFov = 20;
-		}
+		deltaFov = deplzoom*5;
+		if (deltaFov>20)
+			deltaFov = 20;
 	}
 
 	if (deltaFov != 0 )
@@ -618,7 +609,32 @@
 		if (!move.targetObject.isNull())
 		{
 			// if zooming in, object may be moving so be sure to zoom to latest position
-			move.aim = core->altAzToJ2000(move.targetObject->getAltAzPosAuto(core), StelCore::RefractionOff);
+			// In case we have offset center, we want object still visible in center.
+			// Note that if we do not center on an object, we set view direction of the potentially offset screen center!
+			// This is by design, to allow accurate setting of display coordinates.
+			Vec3d v;
+			switch (mountMode)
+			{
+				case MountAltAzimuthal:
+					v = move.targetObject->getAltAzPosAuto(core);
+					break;
+				case MountEquinoxEquatorial:
+					v = move.targetObject->getEquinoxEquatorialPos(core);
+					break;
+				case MountGalactic:
+					v = move.targetObject->getGalacticPos(core);
+					break;
+				default:
+					qWarning() << "StelMovementMgr: unexpected mountMode" << mountMode;
+					Q_ASSERT(0);
+			}
+
+			double lat, lon;
+			StelUtils::rectToSphe(&lon, &lat, v);
+			float altOffset=core->getCurrentStelProjectorParams().viewportCenterOffset[1]*currentFov*M_PI/180.0f;
+			lat+=altOffset;
+			StelUtils::spheToRect(lon, lat, v);
+			move.aim=mountFrameToJ2000(v);
 			move.aim.normalize();
 			move.aim*=2.;
 		}
@@ -686,8 +702,30 @@
 	{
 		if (flagTracking && objectMgr->getWasSelected()) // Equatorial vision vector locked on selected object
 		{
-			Vec3d v = objectMgr->getSelectedObject()[0]->getAltAzPosAuto(core);
-			setViewDirectionJ2000(core->altAzToJ2000(v, StelCore::RefractionOff));
+			Vec3d v;
+			switch (mountMode)
+			{
+				case MountAltAzimuthal:
+					v = objectMgr->getSelectedObject()[0]->getAltAzPosAuto(core);
+					break;
+				case MountEquinoxEquatorial:
+					v = objectMgr->getSelectedObject()[0]->getEquinoxEquatorialPos(core);
+					break;
+				case MountGalactic:
+					v = objectMgr->getSelectedObject()[0]->getGalacticPos(core);
+					break;
+				default:
+					qWarning() << "StelMovementMgr: unexpected mountMode" << mountMode;
+					Q_ASSERT(0);
+			}
+
+			double lat, lon; // general: longitudinal, latitudinal
+			StelUtils::rectToSphe(&lon, &lat, v);
+			float latOffset=core->getCurrentStelProjectorParams().viewportCenterOffset[1]*currentFov*M_PI/180.0f;
+			lat+=latOffset;
+			StelUtils::spheToRect(lon, lat, v);
+
+			setViewDirectionJ2000(mountFrameToJ2000(v));
 		}
 		else
 		{
@@ -705,7 +743,7 @@
 	}
 }
 
-// Go and zoom to the selected object.
+// Go and zoom to the selected object. (Action linked to key, default "/")
 void StelMovementMgr::autoZoomIn(float moveDuration, bool allowManualZoom)
 {
 	if (!objectMgr->getWasSelected())
@@ -716,7 +754,7 @@
 	float manualMoveDuration;
 	if (!getFlagTracking())
 	{
-		setFlagTracking(true);
+		setFlagTracking(true); // includes a call to moveToObject(), but without zooming=1!
 		moveToObject(objectMgr->getSelectedObject()[0], moveDuration, 1);
 		manualMoveDuration = moveDuration;
 	}
@@ -784,7 +822,7 @@
 	}
 }
 
-
+// This is called when you press SPACEBAR: slowly centering&tracking object
 void StelMovementMgr::setFlagTracking(bool b)
 {
 	if (!b || !objectMgr->getWasSelected())
@@ -801,6 +839,7 @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // Move to the given J2000 equatorial position
+
 void StelMovementMgr::moveToJ2000(const Vec3d& aim, float moveDuration, int zooming)
 {
 	moveDuration /= movementsSpeedFactor;
@@ -935,23 +974,64 @@
 		// Use a smooth function
 		double c;
 
-		if( zoomMove.start > zoomMove.aim )
+		if( zoomMove.startFov > zoomMove.aimFov )
 		{
-			// slow down as approach final view
+			// slow down as we approach final view
 			c = 1 - (1-zoomMove.coef)*(1-zoomMove.coef)*(1-zoomMove.coef);
 		}
 		else
 		{
-			// speed up as leave zoom target
+			// speed up as we leave zoom target
 			c = (zoomMove.coef)*(zoomMove.coef)*(zoomMove.coef);
 		}
 
-		setFov(zoomMove.start + (zoomMove.aim - zoomMove.start) * c);
+		double newFov=zoomMove.startFov + (zoomMove.aimFov - zoomMove.startFov) * c;
+
 		zoomMove.coef+=zoomMove.speed*deltaTime*1000;
 		if (zoomMove.coef>=1.)
 		{
 			flagAutoZoom = 0;
-			setFov(zoomMove.aim);
+			newFov=zoomMove.aimFov;
+		}
+
+		setFov(newFov); // updates currentFov->don't use newFov later!
+
+		// In case we have offset center, we want object still visible in center.
+		if (flagTracking && objectMgr->getWasSelected()) // vision vector locked on selected object
+		{
+			Vec3d v;
+			switch (mountMode)
+			{
+				case MountAltAzimuthal:
+					v = objectMgr->getSelectedObject()[0]->getAltAzPosAuto(core);
+					break;
+				case MountEquinoxEquatorial:
+					v = objectMgr->getSelectedObject()[0]->getEquinoxEquatorialPos(core);
+					break;
+				case MountGalactic:
+					v = objectMgr->getSelectedObject()[0]->getGalacticPos(core);
+					break;
+				default:
+					qWarning() << "StelMovementMgr: unexpected mountMode" << mountMode;
+					Q_ASSERT(0);
+			}
+
+			double lat, lon; // general: longitudinal, latitudinal
+			StelUtils::rectToSphe(&lon, &lat, v);
+			float latOffset=core->getCurrentStelProjectorParams().viewportCenterOffset[1]*currentFov*M_PI/180.0f;
+			lat+=latOffset;
+			StelUtils::spheToRect(lon, lat, v);
+
+			if (flagAutoMove)
+			{
+				move.aim=mountFrameToJ2000(v);
+				move.aim.normalize();
+				move.aim*=2.;
+			}
+			else
+			{
+				setViewDirectionJ2000(mountFrameToJ2000(v));
+			}
 		}
 	}
 }
@@ -961,8 +1041,8 @@
 {
 	moveDuration /= movementsSpeedFactor;
 
-	zoomMove.aim=aim_fov;
-	zoomMove.start=currentFov;
+	zoomMove.aimFov=aim_fov;
+	zoomMove.startFov=currentFov;
 	zoomMove.speed=1.f/(moveDuration*1000);
 	zoomMove.coef=0.;
 	flagAutoZoom = true;
@@ -991,7 +1071,7 @@
 
 double StelMovementMgr::getAimFov(void) const
 {
-	return (flagAutoZoom ? zoomMove.aim : currentFov);
+	return (flagAutoZoom ? zoomMove.aimFov : currentFov);
 }
 
 void StelMovementMgr::setMaxFov(double max)

=== modified file 'src/core/StelMovementMgr.hpp'
--- src/core/StelMovementMgr.hpp	2015-03-25 18:18:33 +0000
+++ src/core/StelMovementMgr.hpp	2015-07-24 14:57:31 +0000
@@ -1,6 +1,7 @@
 /*
  * Stellarium
  * Copyright (C) 2007 Fabien Chereau
+ * Copyright (C) 2015 Georg Zotti (offset view adaptations)
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -38,6 +39,8 @@
 public:
 
 	//! Possible mount modes defining the reference frame in which head movements occur.
+	//! MountGalactic is currently only available via scripting API: core.clear("galactic")
+	// TODO: add others like MountEcliptical
 	enum MountMode { MountAltAzimuthal, MountEquinoxEquatorial, MountGalactic};
 
 	StelMovementMgr(StelCore* core);
@@ -157,7 +160,7 @@
 
 	//! Change the zoom level.
 	//! @param aimFov The desired field of view in degrees.
-	//! @param moveDuration The time that the operation should take to complete.
+	//! @param moveDuration The time that the operation should take to complete. [seconds]
 	void zoomTo(double aimFov, float moveDuration = 1.);
 	//! Get the current Field Of View in degrees
 	double getCurrentFov() const {return currentFov;}
@@ -221,10 +224,10 @@
 	Vec3d j2000ToMountFrame(const Vec3d& v) const;
 	Vec3d mountFrameToJ2000(const Vec3d& v) const;
 
-	double currentFov; // The current FOV in degree
+	double currentFov; // The current FOV in degrees
 	double initFov;    // The FOV at startup
-	double minFov;     // Minimum FOV in degree
-	double maxFov;     // Maximum FOV in degree
+	double minFov;     // Minimum FOV in degrees
+	double maxFov;     // Maximum FOV in degrees
 	double initConstellationIntensity;   // The initial constellation art intensity (level at startup)
 
 	void setFov(double f)
@@ -287,7 +290,7 @@
 	double deltaFov,deltaAlt,deltaAz; // View movement
 
 	bool flagManualZoom;     // Define whether auto zoom can go further
-	float autoMoveDuration; // Duration of movement for the auto move to a selected objectin seconds
+	float autoMoveDuration; // Duration of movement for the auto move to a selected object in seconds
 
 	// Mouse control options
 	bool isDragging, hasDragged;
@@ -311,10 +314,15 @@
 
 	//! @internal
 	//! Store data for auto-zoom.
+	// Components:
+	// startFov: field of view at start
+	// aimFov: intended field of view at end of zoom move
+	// speed: rate of change. UNITS?
+	// coef: set to 0 at begin of zoom, will increase to 1 during autozoom motion.
 	struct AutoZoom
 	{
-		double start;
-		double aim;
+		double startFov;
+		double aimFov;
 		float speed;
 		float coef;
 	};

=== modified file 'src/core/StelProjector.cpp'
--- src/core/StelProjector.cpp	2014-11-06 10:59:07 +0000
+++ src/core/StelProjector.cpp	2015-07-24 14:57:31 +0000
@@ -22,6 +22,8 @@
 
 #include "StelProjector.hpp"
 #include "StelProjectorClasses.hpp"
+#include "StelApp.hpp"
+#include "StelCore.hpp"
 
 #include <QDebug>
 #include <QString>
@@ -385,7 +387,9 @@
 void StelProjector::computeBoundingCap()
 {
 	bool ok = unProject(viewportXywh[0]+0.5f*viewportXywh[2], viewportXywh[1]+0.5f*viewportXywh[3], boundingCap.n);
-	Q_ASSERT(ok);	// The central point should be at a valid position by definition
+	// The central point should be at a valid position by definition.
+	// When center is offset, this assumption may not hold however.
+	Q_ASSERT(ok || (StelApp::getInstance().getCore()->getCurrentStelProjectorParams().viewportCenterOffset.lengthSquared()>0.0) );
 	const bool needNormalization = fabs(boundingCap.n.lengthSquared()-1.)>0.00000001;
 
 	// Now need to determine the aperture

=== modified file 'src/core/StelProjector.hpp'
--- src/core/StelProjector.hpp	2014-11-06 10:59:07 +0000
+++ src/core/StelProjector.hpp	2015-07-24 14:57:31 +0000
@@ -102,6 +102,7 @@
 			, zNear(0.f)
 			, zFar(0.f)
 			, viewportCenter(128.f, 128.f)
+			, viewportCenterOffset(0.f, 0.f)
 			, viewportFovDiameter(0.f)
 			, flipHorz(false)
 			, flipVert(false)
@@ -114,6 +115,7 @@
 		StelProjectorMaskType maskType; //! The current projector mask
 		float zNear, zFar;              //! Near and far clipping planes
 		Vec2f viewportCenter;           //! Viewport center in screen pixel
+		Vec2f viewportCenterOffset;     //! GZ: Viewport center's offset in fractions of screen width/height. Usable e.g. in cylindrical projection to move horizon down.
 		float viewportFovDiameter;      //! diameter of the FOV disk in pixel
 		bool flipHorz, flipVert;        //! Whether to flip in horizontal or vertical directions
 		float devicePixelsPerPixel;     //! The number of device pixel per "Device Independent Pixels" (value is usually 1, but 2 for mac retina screens)

=== modified file 'src/gui/ConfigurationDialog.cpp'
--- src/gui/ConfigurationDialog.cpp	2015-05-23 20:00:14 +0000
+++ src/gui/ConfigurationDialog.cpp	2015-07-24 14:57:31 +0000
@@ -695,6 +695,8 @@
 	conf->setValue("gui/flag_show_flip_buttons", gui->getFlagShowFlipButtons());
 	conf->setValue("video/viewport_effect", StelApp::getInstance().getViewportEffect());
 	conf->setValue("projection/viewport", StelProjector::maskTypeToString(proj->getMaskType()));
+	conf->setValue("projection/viewport_center_offset_x", core->getCurrentStelProjectorParams().viewportCenterOffset[0]);
+	conf->setValue("projection/viewport_center_offset_y", core->getCurrentStelProjectorParams().viewportCenterOffset[1]);
 	conf->setValue("viewing/flag_gravity_labels", proj->getFlagGravityLabels());
 	conf->setValue("navigation/auto_zoom_out_resets_direction", mvmgr->getFlagAutoZoomOutResetsDirection());
 	conf->setValue("gui/flag_mouse_cursor_timeout", StelMainView::getInstance().getFlagCursorTimeout());

=== modified file 'src/gui/ViewDialog.cpp'
--- src/gui/ViewDialog.cpp	2015-05-23 20:00:14 +0000
+++ src/gui/ViewDialog.cpp	2015-07-24 14:57:31 +0000
@@ -134,8 +134,11 @@
 	connect(ui->closeStelWindow, SIGNAL(clicked()), this, SLOT(close()));
 
 	populateLists();
+	ui->viewportOffsetSpinBox->setValue((int) round(StelApp::getInstance().getCore()->getCurrentStelProjectorParams().viewportCenterOffset[1] * 100.0f));
+
 	connect(ui->culturesListWidget, SIGNAL(currentTextChanged(const QString&)), this, SLOT(skyCultureChanged(const QString&)));
 	connect(ui->projectionListWidget, SIGNAL(currentTextChanged(const QString&)), this, SLOT(projectionChanged(const QString&)));
+	connect(ui->viewportOffsetSpinBox, SIGNAL(valueChanged(int)), this, SLOT(viewportVerticalShiftChanged(int)));
 	connect(ui->landscapesListWidget, SIGNAL(itemClicked(QListWidgetItem*)), this, SLOT(landscapeChanged(QListWidgetItem*)));
 
 	// Connect and initialize checkboxes and other widgets
@@ -602,6 +605,18 @@
 	ui->projectionTextBrowser->setHtml(core->getProjection(StelCore::FrameJ2000)->getHtmlSummary());
 }
 
+void ViewDialog::viewportVerticalShiftChanged(const int shift)
+{
+	StelCore* core = StelApp::getInstance().getCore();
+	StelProjector::StelProjectorParams params=core->getCurrentStelProjectorParams();
+	params.viewportCenterOffset[1]=qMax(-0.5f, qMin(shift/100.0f, 0.5f)); // Sanity check
+
+	params.viewportCenter.set(params.viewportXywh[0]+(0.5f+params.viewportCenterOffset.v[0])*params.viewportXywh[2],
+				  params.viewportXywh[1]+(0.5f+params.viewportCenterOffset.v[1])*params.viewportXywh[3]);
+
+	core->setCurrentStelProjectorParams(params);
+}
+
 void ViewDialog::landscapeChanged(QListWidgetItem* item)
 {
 	LandscapeMgr* lmgr = GETSTELMODULE(LandscapeMgr);
@@ -612,8 +627,7 @@
 	ui->landscapeTextBrowser->setHtml(lmgr->getCurrentLandscapeHtmlDescription());
 	ui->useAsDefaultLandscapeCheckBox->setChecked(lmgr->getDefaultLandscapeID()==lmgr->getCurrentLandscapeID());
 	ui->useAsDefaultLandscapeCheckBox->setEnabled(lmgr->getDefaultLandscapeID()!=lmgr->getCurrentLandscapeID());
-	//StelSkyDrawer *drawer=StelApp::getInstance().getSkyDrawer();
-	// GZ: Reset values that might have changed.
+	// Reset values that might have changed.
 	ui->showFogCheckBox->setChecked(lmgr->getFlagFog());
 	ui->lightPollutionSpinBox->setValue(StelApp::getInstance().getCore()->getSkyDrawer()->getBortleScaleIndex());
 }
@@ -630,9 +644,6 @@
 {
 	if(atmosphereDialog == NULL)
 		atmosphereDialog = new AtmosphereDialog();
-	//ui->temperatureDoubleSpinBox->setValue(StelApp::getInstance().getCore()->getSkyDrawer()->getAtmosphereTemperature());
-	//ui->extinctionDoubleSpinBox->setValue(StelApp::getInstance().getCore()->getSkyDrawer()->getExtinctionCoefficient());
-	//ui->pressureDoubleSpinBox->setValue(StelApp::getInstance().getCore()->getSkyDrawer()->getAtmospherePressure());
 
 	atmosphereDialog->setVisible(true);
 }

=== modified file 'src/gui/ViewDialog.hpp'
--- src/gui/ViewDialog.hpp	2015-04-11 14:08:59 +0000
+++ src/gui/ViewDialog.hpp	2015-07-24 14:57:31 +0000
@@ -50,6 +50,7 @@
 	void populateLists();
 	void skyCultureChanged(const QString& cultureName);
 	void projectionChanged(const QString& projectionName);
+	void viewportVerticalShiftChanged(const int shift);
 	void landscapeChanged(QListWidgetItem* item);
 	void setZhrFromControls(int zhr);
 	void updateZhrDescription();

=== modified file 'src/gui/viewDialog.ui'
--- src/gui/viewDialog.ui	2015-05-23 20:00:14 +0000
+++ src/gui/viewDialog.ui	2015-07-24 14:57:31 +0000
@@ -340,7 +340,7 @@
       <item row="1" column="0">
        <widget class="QStackedWidget" name="stackedWidget">
         <property name="currentIndex">
-         <number>0</number>
+         <number>1</number>
         </property>
         <widget class="QWidget" name="page">
          <layout class="QGridLayout" name="gridLayout">
@@ -1636,11 +1636,68 @@
               </widget>
              </item>
              <item>
-              <widget class="QTextBrowser" name="projectionTextBrowser">
-               <property name="openExternalLinks">
-                <bool>true</bool>
-               </property>
-              </widget>
+              <layout class="QVBoxLayout" name="projectionDetailsVerticalLayout">
+               <item>
+                <widget class="QTextBrowser" name="projectionTextBrowser">
+                 <property name="openExternalLinks">
+                  <bool>true</bool>
+                 </property>
+                </widget>
+               </item>
+               <item>
+                <layout class="QHBoxLayout" name="viewportOffsetHorizontalLayout">
+                 <item>
+                  <widget class="QLabel" name="viewportOffsetLabel">
+                   <property name="text">
+                    <string>Vertical viewport offset</string>
+                   </property>
+                  </widget>
+                 </item>
+                 <item>
+                  <widget class="QSpinBox" name="viewportOffsetSpinBox">
+                   <property name="sizePolicy">
+                    <sizepolicy hsizetype="Preferred" vsizetype="Fixed">
+                     <horstretch>0</horstretch>
+                     <verstretch>0</verstretch>
+                    </sizepolicy>
+                   </property>
+                   <property name="minimum">
+                    <number>-50</number>
+                   </property>
+                   <property name="maximum">
+                    <number>50</number>
+                   </property>
+                  </widget>
+                 </item>
+                 <item>
+                  <widget class="QLabel" name="percentLabel">
+                   <property name="sizePolicy">
+                    <sizepolicy hsizetype="Minimum" vsizetype="Preferred">
+                     <horstretch>0</horstretch>
+                     <verstretch>0</verstretch>
+                    </sizepolicy>
+                   </property>
+                   <property name="text">
+                    <string>%</string>
+                   </property>
+                  </widget>
+                 </item>
+                 <item>
+                  <spacer name="horizontalSpacer">
+                   <property name="orientation">
+                    <enum>Qt::Horizontal</enum>
+                   </property>
+                   <property name="sizeHint" stdset="0">
+                    <size>
+                     <width>40</width>
+                     <height>20</height>
+                    </size>
+                   </property>
+                  </spacer>
+                 </item>
+                </layout>
+               </item>
+              </layout>
              </item>
             </layout>
            </widget>
@@ -2171,7 +2228,6 @@
   <tabstop>showConstellationBoundariesCheckBox</tabstop>
   <tabstop>showConstellationArtCheckBox</tabstop>
   <tabstop>constellationArtBrightnessSpinBox</tabstop>
-  <tabstop>projectionTextBrowser</tabstop>
   <tabstop>landscapeTextBrowser</tabstop>
   <tabstop>showGroundCheckBox</tabstop>
   <tabstop>showFogCheckBox</tabstop>

=== modified file 'src/scripting/StelMainScriptAPI.cpp'
--- src/scripting/StelMainScriptAPI.cpp	2015-04-21 20:23:14 +0000
+++ src/scripting/StelMainScriptAPI.cpp	2015-07-24 14:57:31 +0000
@@ -1072,6 +1072,40 @@
 		lmgr->setFlagFog(false);
 		zl->setFlagShow(false);
 	}
+	else if (state.toLower() == "galactic")
+	{
+		movmgr->setMountMode(StelMovementMgr::MountGalactic);
+		skyd->setFlagTwinkle(false);
+		skyd->setFlagLuminanceAdaptation(false);
+		ssmgr->setFlagPlanets(false);
+		ssmgr->setFlagHints(false);
+		ssmgr->setFlagOrbits(false);
+		ssmgr->setFlagMoonScale(false);
+		ssmgr->setFlagTrails(false);
+		mmgr->setZHR(0);
+		glmgr->setFlagAzimuthalGrid(false);
+		glmgr->setFlagGalacticGrid(false);
+		glmgr->setFlagEquatorGrid(false);
+		glmgr->setFlagEquatorLine(false);
+		glmgr->setFlagEclipticLine(false);
+		glmgr->setFlagMeridianLine(false);
+		glmgr->setFlagLongitudeLine(false);
+		glmgr->setFlagHorizonLine(false);
+		glmgr->setFlagGalacticEquatorLine(false);
+		glmgr->setFlagEquatorJ2000Grid(false);
+		lmgr->setFlagCardinalsPoints(false);
+		cmgr->setFlagLines(false);
+		cmgr->setFlagLabels(false);
+		cmgr->setFlagBoundaries(false);
+		cmgr->setFlagArt(false);
+		smgr->setFlagLabels(false);
+		ssmgr->setFlagLabels(false);
+		nmgr->setFlagHints(false);
+		lmgr->setFlagLandscape(false);
+		lmgr->setFlagAtmosphere(false);
+		lmgr->setFlagFog(false);
+		zl->setFlagShow(false);
+	}
 	else
 	{
 		qWarning() << "WARNING clear(" << state << ") - state not known";

=== modified file 'src/scripting/StelMainScriptAPI.hpp'
--- src/scripting/StelMainScriptAPI.hpp	2015-07-05 19:50:54 +0000
+++ src/scripting/StelMainScriptAPI.hpp	2015-07-24 14:57:31 +0000
@@ -219,6 +219,7 @@
 	//! - starchart : equatorial mount, constellation lines,
 	//!   no landscape, atmosphere etc.  labels & markers on.
 	//! - deepspace : like starchart, but no planets, no eq.grid, no markers, no lines.
+	//! - galactic  : like deepspace, but in galactic coordinate system.
 	//! @param state the name of a preset state.
 	void clear(const QString& state="natural");