uk.ac.starlink.ttools.plot2
Interface Surface

All Known Implementing Classes:
CubeSurface, PlaneSurface, SkySurface, TimeSurface

public interface Surface

Defines the graphical area on which plots are painted. It maps data space coordinates to graphics coordinates (and possibly vice versa) and paints axes.

Since:
11 Feb 2013
Author:
Mark Taylor
See Also:
SurfaceFactory

Method Summary
 boolean dataToGraphics(double[] dataPos, boolean visibleOnly, Point2D.Double gPos)
          Converts a data space position to a graphics position.
 boolean dataToGraphicsOffset(double[] dataPos0, Point2D.Double gpos0, double[] dataPos1, boolean visibleOnly, Point2D.Double gPos1)
          Converts an offset data space position to a graphics position.
 String formatPosition(double[] dataPos)
          Formats the given data space position as a coordinate string.
 Captioner getCaptioner()
          Returns a captioner suitable for drawing general purpose labels annotating the plot.
 int getDataDimCount()
          Returns the dimensionality of the data space used by this plot surface.
 Rectangle getPlotBounds()
          Returns the rectangle within which all of the plot data will appear.
 Insets getPlotInsets(boolean withScroll)
          Returns the insets that this surface would like to reserve outside the plot bounds.
 double[] graphicsToData(Point2D gPos, Iterable<double[]> dposIt)
          Attempst to turn a graphics position into a data position.
 void paintBackground(Graphics g)
          Paints the plot surface background.
 void paintForeground(Graphics g)
          Paints the plot surface foreground.
 

Method Detail

getPlotBounds

Rectangle getPlotBounds()
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.

Returns:
plot data area bounds

getPlotInsets

Insets getPlotInsets(boolean withScroll)
Returns the insets that this surface would like to reserve outside the plot bounds. This is space outside the rectangle returned by 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.

Parameters:
withScroll - true to reserve space for nicer scrolling
Returns:
plot data area insets

paintBackground

void paintBackground(Graphics g)
Paints the plot surface background. Anything that appears within the plot bounds underneath the data markings must go here.

Parameters:
g - graphics context

paintForeground

void paintForeground(Graphics g)
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.

Parameters:
g - graphics context

getDataDimCount

int getDataDimCount()
Returns the dimensionality of the data space used by this plot surface.

Returns:
number of elements in data space coordinate array

dataToGraphics

boolean dataToGraphics(double[] dataPos,
                       boolean visibleOnly,
                       Point2D.Double gPos)
Converts a data space position to a graphics position. If visibleOnly is true, then if the return value is true, the exit value of gPos is guaranteed to be within the plot bounds of this surface.

If visibleOnly is false, there are no guarantees about the exit value of gPos, and its coordinates could be infinite or NaN. In this case you might want to perform additional checking, for instance with the utility methods PlotUtil.isPointFinite or isPointReal.

Parameters:
dataPos - dataDimCount-element array containing data space coordinates
visibleOnly - if true, then the conversion will only succeed when the result falls within the plot bounds of this surface
gPos - point object into which the graphics position will be written on success
Returns:
true iff the conversion succeeds

dataToGraphicsOffset

boolean dataToGraphicsOffset(double[] dataPos0,
                             Point2D.Double gpos0,
                             double[] dataPos1,
                             boolean visibleOnly,
                             Point2D.Double gPos1)
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 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.

Parameters:
dataPos0 - context position in data space
gpos0 - context position in graphics space (result of calling dataToGraphics on dpos0)
dataPos1 - query position in data space
visibleOnly - if true, the call only succeeds if the result is within the plot bounds of this surface
gPos1 - point object to which the graphics position of dpos1 will be written on success
Returns:
true for success, false for no result

graphicsToData

double[] graphicsToData(Point2D gPos,
                        Iterable<double[]> dposIt)
Attempst 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. The dposIt argument can optionally be supplied to cope with such instances. If a data pos cannot be determined, null is returned. If dposIt is absent, the method will run quickly. If it's present, it may or may not run slowly.

Parameters:
gPos - graphics point
dposIt - 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

formatPosition

String formatPosition(double[] dataPos)
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.

Parameters:
dataPos - dataDimCount-element array giving data space position
Returns:
human-readable string representing position

getCaptioner

Captioner getCaptioner()
Returns a captioner suitable for drawing general purpose labels annotating the plot.

Returns:
captioner


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