Class SkySurface
- java.lang.Object
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- uk.ac.starlink.ttools.plot2.geom.SkySurface
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- All Implemented Interfaces:
Surface
public class SkySurface extends java.lang.Object implements Surface
Surface implementation for plotting on the celestial sphere. The data coordinates are direction cosines: 3-element arrays containing normalised X,Y,Z coordinates, where each coordinate is in the range -1..+1 and the sum of squares is 1.- Since:
- 20 Feb 2013
- Author:
- Mark Taylor
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Constructor Summary
Constructors Constructor Description SkySurface(java.awt.Rectangle plotBounds, Projection projection, double[] rotmat, double zoom, double xoff, double yoff, SkySys viewSystem, SkyAxisLabeller axLabeller, java.awt.Color gridColor, java.awt.Color axlabelColor, java.awt.Color scalebarColor, boolean sexagesimal, double crowd, Captioner captioner, boolean antialias)
Constructor.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description GridLiner
createGridder(Rotation rotation, boolean sexagesimal, double loncrowd, double latcrowd)
Attempts to construct a GridLiner object to draw grid lines on this plot.LabelledLine
createLine(java.awt.geom.Point2D gp1, java.awt.geom.Point2D gp2)
Returns a labelled line corresponding to the (shorter) great circle arc between two graphics points.boolean
dataToGraphics(double[] dpos, boolean visibleOnly, java.awt.geom.Point2D.Double gpos)
Converts a data space position to a graphics position.boolean
dataToGraphicsOffset(double[] dpos0, java.awt.geom.Point2D.Double gpos0, double[] dpos1, boolean visibleOnly, java.awt.geom.Point2D.Double gpos1)
Converts an offset data space position to a graphics position.boolean
equals(java.lang.Object o)
SkyAspect
flatPan(java.awt.geom.Point2D pos0, java.awt.geom.Point2D pos1)
Pan gesture which just translates the entire graphics plane.SkyAspect
flatZoom(java.awt.geom.Point2D pos, double factor)
Zoom gesture which just magnifies the entire graphics plane.java.lang.String
formatPosition(double[] dpos)
Formats the given data space position as a coordinate string.static java.lang.String
formatPositionDec(double lonRad, double latRad, double pixRad)
Formats a lon/lat position as decimal given the approximate size of a screen pixel.static java.lang.String
formatPositionSex(double lonRad, double latRad, double pixRad)
Formats a lon/lat position as sexagesimal given the approximate size of a screen pixel.Captioner
getCaptioner()
Returns a captioner suitable for drawing general purpose labels annotating the plot.int
getDataDimCount()
Returns 3.double
getOffsetX()
Returns the dimensionless X offset of the plot centre from the plot bounds centre.double
getOffsetY()
Returns the dimensionless Y offset of the plot centre from the plot bounds centre.java.awt.Rectangle
getPlotBounds()
Returns the rectangle within which all of the plot data will appear.java.awt.Insets
getPlotInsets(boolean withScroll)
Returns the insets that this surface would like to reserve outside the plot bounds.Projection
getProjection()
Returns the projection used by this sky surface.double[]
getRotation()
Returns the rotation matrix corresponding to this view of the sky.java.awt.Point
getSkyCenter()
Returns the screen position corresponding to the center of the projection used by this surface.java.awt.Shape
getSkyShape()
Returns a shape that gives the boundary of the sky projection in graphics coordinates.SkySys
getViewSystem()
Returns the sky system into which coordinates are projected.double
getZoom()
Returns the zoom factor; 1 means the sky is approximately the same size as the plot bounds.double[]
graphicsToData(java.awt.geom.Point2D gpos)
Attempts to turn a graphics position into a sky position.double[]
graphicsToData(java.awt.geom.Point2D gpos, java.lang.Iterable<double[]> dposIt)
Attempts to turn a graphics position into a data position.int
hashCode()
boolean
isContinuousLine(double[] dpos0, double[] dpos1)
Indicates whether a line in graphics space between two given data space positions is continuous.void
paintBackground(java.awt.Graphics g)
Paints the plot surface background.void
paintForeground(java.awt.Graphics g)
Paints the plot surface foreground.double
pixelAreaSteradians()
Returns the approximate solid angle covered by a screen pixel in steradians.double
pixelAreaSteradians(java.awt.geom.Point2D gpos)
Returns the solid angle covered by a given graphics pixel in steradians.SkyAspect
projPan(java.awt.geom.Point2D pos0, java.awt.geom.Point2D pos1)
Pan gesture which attempts to rotate the sky while leaving the size and location of the graphics plane unchanged.SkyAspect
projZoom(java.awt.geom.Point2D pos, double factor)
Zoom gesture which attempts to zoom the sky, with the cursor staying at the same sky position, while leaving the size and location of the graphics plane unchanged.SkyAspect
reframe(java.awt.geom.Point2D center, double factor)
Returns a plot aspect giving the data region defined by a graphics position and zoom factor adjustment.double
screenDistanceRadians(java.awt.geom.Point2D gp1, java.awt.geom.Point2D gp2)
Returns the distance along a great circle in radians between two graphics positions.
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Constructor Detail
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SkySurface
public SkySurface(java.awt.Rectangle plotBounds, Projection projection, double[] rotmat, double zoom, double xoff, double yoff, SkySys viewSystem, SkyAxisLabeller axLabeller, java.awt.Color gridColor, java.awt.Color axlabelColor, java.awt.Color scalebarColor, boolean sexagesimal, double crowd, Captioner captioner, boolean antialias)
Constructor.- Parameters:
plotBounds
- graphics region within which the plot must fallprojection
- sky projectionrotmat
- 9-element rotation matrixzoom
- zoom factor; 1 means the sky is approximately the same size as plot boundsxoff
- x offset of plot centre from plot bounds centre in dimensionless units; 0 is centredyoff
- y offset of plot centre from plot bounds centre in dimensionless units; 0 is centredviewSystem
- sky system into which coordinates are projectedaxLabeller
- sky axis labelling objectgridColor
- colour for grid drawing, or null if no gridaxlabelColor
- colour for axis labels, or null if no labelsscalebarColor
- colour for scale bar, or null if not drawnsexagesimal
- whether to use sexagesimal coordinatescrowd
- tick mark crowding factor, 1 is normalcaptioner
- text rendering objectantialias
- whether to antialias grid lines
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Method Detail
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getDataDimCount
public int getDataDimCount()
Returns 3.- Specified by:
getDataDimCount
in interfaceSurface
- Returns:
- number of elements in data space coordinate array
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getPlotBounds
public java.awt.Rectangle getPlotBounds()
Description copied from interface:Surface
Returns the rectangle within which all of the plot data will appear. This includes anything that might get drawn by a plot layer, but does not necessarily include axis labels etc.- Specified by:
getPlotBounds
in interfaceSurface
- Returns:
- plot data area bounds
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getPlotInsets
public java.awt.Insets getPlotInsets(boolean withScroll)
Description copied from interface:Surface
Returns the insets that this surface would like to reserve outside the plot bounds. This is space outside the rectangle returned bySurface.getPlotBounds()
to be used for axis labels etc.If the
withScroll
parameter is set, then an attempt will be made to return insets that will not alter if the current plot is scrolled around a moderate amount. For a one-time plot that's not important, but for an interactive plot it prevents the actual plot position jumping around to accommodate more or less space on the axes according to exactly where ticks happen to fall on the axes.This method is supposed to return only the space that may actually be touched by the plot. The calling code may wish to apply additional padding on top of this for cosmetic reasons.
- Specified by:
getPlotInsets
in interfaceSurface
- Parameters:
withScroll
- true to reserve space for nicer scrolling- Returns:
- plot data area insets
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paintBackground
public void paintBackground(java.awt.Graphics g)
Description copied from interface:Surface
Paints the plot surface background. Anything that appears within the plot bounds underneath the data markings must go here.- Specified by:
paintBackground
in interfaceSurface
- Parameters:
g
- graphics context
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paintForeground
public void paintForeground(java.awt.Graphics g)
Description copied from interface:Surface
Paints the plot surface foreground. Anything that appears on top of the data markings or outside the plot bounds must go here. This may include axes.- Specified by:
paintForeground
in interfaceSurface
- Parameters:
g
- graphics context
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getCaptioner
public Captioner getCaptioner()
Description copied from interface:Surface
Returns a captioner suitable for drawing general purpose labels annotating the plot.- Specified by:
getCaptioner
in interfaceSurface
- Returns:
- captioner
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getProjection
public Projection getProjection()
Returns the projection used by this sky surface.- Returns:
- projection
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getRotation
public double[] getRotation()
Returns the rotation matrix corresponding to this view of the sky.- Returns:
- 9-element rotation matrix
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getZoom
public double getZoom()
Returns the zoom factor; 1 means the sky is approximately the same size as the plot bounds.- Returns:
- zoom factor
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getOffsetX
public double getOffsetX()
Returns the dimensionless X offset of the plot centre from the plot bounds centre.- Returns:
- dimensionless X offset
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getOffsetY
public double getOffsetY()
Returns the dimensionless Y offset of the plot centre from the plot bounds centre.- Returns:
- dimensionless Y offset
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getViewSystem
public SkySys getViewSystem()
Returns the sky system into which coordinates are projected.- Returns:
- view sky system
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createGridder
public GridLiner createGridder(Rotation rotation, boolean sexagesimal, double loncrowd, double latcrowd)
Attempts to construct a GridLiner object to draw grid lines on this plot.The work is done by classes from the SkyView package.
- Parameters:
rotation
- additional rotation to apply to sky system before grid lines are plotted; may be null for no additional rotationsexagesimal
- true for sexagesimal labels, false for decimalloncrowd
- longitude tick mark crowding factor, 1 is normallatcrowd
- latitude tick mark crowding factor, 1 is normal- Returns:
- gridliner, or null on failure
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dataToGraphics
public boolean dataToGraphics(double[] dpos, boolean visibleOnly, java.awt.geom.Point2D.Double gpos)
Description copied from interface:Surface
Converts a data space position to a graphics position. IfvisibleOnly
is true, then if the return value is true, the exit value ofgPos
is guaranteed to be within the plot bounds of this surface.If
visibleOnly
is false, there are no guarantees about the exit value ofgPos
, and its coordinates could be infinite or NaN. In this case you might want to perform additional checking, for instance with the utility methodsPlotUtil.isPointFinite
orisPointReal
.- Specified by:
dataToGraphics
in interfaceSurface
- Parameters:
dpos
- dataDimCount-element array containing data space coordinatesvisibleOnly
- if true, then the conversion will only succeed when the result falls within the plot bounds of this surfacegpos
- point object into which the graphics position will be written on success- Returns:
- true iff the conversion succeeds
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dataToGraphicsOffset
public boolean dataToGraphicsOffset(double[] dpos0, java.awt.geom.Point2D.Double gpos0, double[] dpos1, boolean visibleOnly, java.awt.geom.Point2D.Double gpos1)
Description copied from interface:Surface
Converts an offset data space position to a graphics position. Context is given in the form of an existing converted nearby point (both data and graphics positions).This (somewhat hacky) method is required for surfaces in which a data position may map to more than one position in graphics space, for instance sky surfaces with discontinuous longitude. The result does not need to be the same as the result of calling
Surface.dataToGraphics(double[], boolean, java.awt.geom.Point2D.Double)
, and is not required to be a legal graphics position, but it must make visual sense, for instance when plotting error bars. The semantics of a "nearby point" is not very well defined. There are probably situations in which calling this will not give the result that's wanted, but they will probably be rare.- Specified by:
dataToGraphicsOffset
in interfaceSurface
- Parameters:
dpos0
- context position in data spacegpos0
- context position in graphics space (result of calling dataToGraphics on dpos0)dpos1
- query position in data spacevisibleOnly
- if true, the call only succeeds if the result is within the plot bounds of this surfacegpos1
- point object to which the graphics position of dpos1 will be written on success- Returns:
- true for success, false for no result
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graphicsToData
public double[] graphicsToData(java.awt.geom.Point2D gpos, java.lang.Iterable<double[]> dposIt)
Description copied from interface:Surface
Attempts to turn a graphics position into a data position. This is not always trivial, for instance in a 3D plot one graphics position maps to a line of data positions. ThedposIt
argument can optionally be supplied to cope with such instances. If a data pos cannot be determined, null is returned. IfdposIt
is absent, the method will run quickly. If it's present, it may or may not run slowly.- Specified by:
graphicsToData
in interfaceSurface
- Parameters:
gpos
- graphics pointdposIt
- iterable over dataDimCount-element arrays representing all the data space positions plotted, or null- Returns:
- dataDimCount-element array giving data space position for
gPos
, or null if it cannot be determined
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graphicsToData
public double[] graphicsToData(java.awt.geom.Point2D gpos)
Attempts to turn a graphics position into a sky position. This convenience function just callsgraphicsToData(gpos,null)
, since the iterable argument is ignored for the SkySurface.- Parameters:
gpos
- graphics position- Returns:
- 3-element unit vector representing data position, or null if gpos out of range
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isContinuousLine
public boolean isContinuousLine(double[] dpos0, double[] dpos1)
Description copied from interface:Surface
Indicates whether a line in graphics space between two given data space positions is continuous.This is not very well-defined, but if drawing a line in graphics coordinates between the graphics coordinates corresponding to the two data coordinates is likely to do something badly wrong, this method should return false. It is intended to deal with the case where a short offset in data coordinates would lead to a line going the wrong way round the sky when it crosses the longitude=+/-PI boundary in an Aitoff projection.
- Specified by:
isContinuousLine
in interfaceSurface
- Parameters:
dpos0
- first dataDimCount-element array containing data space coordinatesdpos1
- second dataDimCount-element array containing data space coordinates- Returns:
- true if drawing a graphics line between the two positions should be OK
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formatPosition
public java.lang.String formatPosition(double[] dpos)
Description copied from interface:Surface
Formats the given data space position as a coordinate string. If possible the returned string should have the same length and formatting over the whole visible plot surface, so that the representation doesn't jump around when the cursor is moved.- Specified by:
formatPosition
in interfaceSurface
- Parameters:
dpos
- dataDimCount-element array giving data space position- Returns:
- human-readable string representing position
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pixelAreaSteradians
public double pixelAreaSteradians()
Returns the approximate solid angle covered by a screen pixel in steradians. It tries to return a representative value for the visible area.- Returns:
- approximate linear size of a screen pixel in radians
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pixelAreaSteradians
public double pixelAreaSteradians(java.awt.geom.Point2D gpos)
Returns the solid angle covered by a given graphics pixel in steradians.- Parameters:
gpos
- position of graphics pixel center- Returns:
- approximate linear size of pixel in radians, or NaN if pixel is not (all) on the sky
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screenDistanceRadians
public double screenDistanceRadians(java.awt.geom.Point2D gp1, java.awt.geom.Point2D gp2)
Returns the distance along a great circle in radians between two graphics positions. The evaluation should be well-conditioned for small or large angles. The given coordinates do not need to be within the graphics bounds, but if they are outside the celestial sphere, NaN will be returned.- Parameters:
gp1
- first positiongp2
- second position- Returns:
- separation between positions in radians, or NaN if one of the positions is not on the sky
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createLine
public LabelledLine createLine(java.awt.geom.Point2D gp1, java.awt.geom.Point2D gp2)
Returns a labelled line corresponding to the (shorter) great circle arc between two graphics points.- Parameters:
gp1
- start point in graphics spacegp2
- end point in graphics space- Returns:
- labelled line, or null if it can't be done, for instance if not both points are on the sky
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formatPositionSex
public static java.lang.String formatPositionSex(double lonRad, double latRad, double pixRad)
Formats a lon/lat position as sexagesimal given the approximate size of a screen pixel. The pixel size is used to determine how much precision to give.- Parameters:
lonRad
- longitude in radianslatRad
- latitude in radianspixRad
- approximate size of a screen pixel in radians
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formatPositionDec
public static java.lang.String formatPositionDec(double lonRad, double latRad, double pixRad)
Formats a lon/lat position as decimal given the approximate size of a screen pixel. The pixel size is used to determine how much precision to give.- Parameters:
lonRad
- longitude in radianslatRad
- latitude in radianspixRad
- approximate size of a screen pixel in radians
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flatPan
public SkyAspect flatPan(java.awt.geom.Point2D pos0, java.awt.geom.Point2D pos1)
Pan gesture which just translates the entire graphics plane.- Parameters:
pos0
- source graphics positionpos1
- destination graphics position- Returns:
- panned sky aspect
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flatZoom
public SkyAspect flatZoom(java.awt.geom.Point2D pos, double factor)
Zoom gesture which just magnifies the entire graphics plane.- Parameters:
pos
- reference graphics positionfactor
- zoom factor- Returns:
- zoomed sky aspect
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projPan
public SkyAspect projPan(java.awt.geom.Point2D pos0, java.awt.geom.Point2D pos1)
Pan gesture which attempts to rotate the sky while leaving the size and location of the graphics plane unchanged. If that functionality is not supported by the projection, it will fall back to flat panning.- Parameters:
pos0
- source graphics positionpos1
- destination graphics position- Returns:
- panned sky aspect
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projZoom
public SkyAspect projZoom(java.awt.geom.Point2D pos, double factor)
Zoom gesture which attempts to zoom the sky, with the cursor staying at the same sky position, while leaving the size and location of the graphics plane unchanged. If that functionality is not supported by the projection, it will fall back to flat zooming.- Parameters:
pos
- reference graphics positionfactor
- zoom factor- Returns:
- zoomed sky aspect
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reframe
public SkyAspect reframe(java.awt.geom.Point2D center, double factor)
Returns a plot aspect giving the data region defined by a graphics position and zoom factor adjustment.- Parameters:
center
- position in current graphics coordinates of the sky position requested as the new centerfactor
- zoom factor (from current)- Returns:
- reframed sky aspect
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getSkyCenter
public java.awt.Point getSkyCenter()
Returns the screen position corresponding to the center of the projection used by this surface. That position will typically, but not necessarily, be the least distorted point. The returned position is not necessarily within the currently visible plot bounds.- Returns:
- central position in graphics coordinates
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getSkyShape
public java.awt.Shape getSkyShape()
Returns a shape that gives the boundary of the sky projection in graphics coordinates.- Returns:
- sky boundary shape
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equals
public boolean equals(java.lang.Object o)
- Overrides:
equals
in classjava.lang.Object
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hashCode
public int hashCode()
- Overrides:
hashCode
in classjava.lang.Object
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