topcat: add plot2 window specifically for histograms

You can already plot histograms in the plane plot, but having a separate
window can set up some defaults in a more convenient way if a histogram
is what you want to plot.

topcat/src/main/uk/ac/starlink/topcat/ControlWindow.java

@@ -119,6 +119,7 @@
 import uk.ac.starlink.topcat.plot.SphereWindow;
 import uk.ac.starlink.topcat.plot2.Control;
 import uk.ac.starlink.topcat.plot2.CubePlotWindow;
+import uk.ac.starlink.topcat.plot2.HistogramPlotWindow;
 import uk.ac.starlink.topcat.plot2.PlanePlotWindow;
 import uk.ac.starlink.topcat.plot2.SkyPlotWindow;
 import uk.ac.starlink.topcat.plot2.SpherePlotWindow;
@@ -437,6 +438,11 @@ public void stateChanged( ChangeEvent evt ) {
                                    "3D plotting window"
                                    + " using spherical polar coordinates",
                                    SpherePlotWindow.class ),
+            new Plot2WindowAction( "Histogram Layer Plot",
+                                   ResourceIcon.PLOT2_HISTOGRAM,
+                                   "Plane plotting window configured for "
+                                   + "convenience for histogram plotting",
+                                   HistogramPlotWindow.class ),
             new Plot2WindowAction( "Time Layer Plot",
                                    ResourceIcon.PLOT2_TIME,
                                    "Time series plotting window",

topcat/src/main/uk/ac/starlink/topcat/ResourceIcon.java

@@ -239,6 +239,7 @@ public class ResourceIcon implements Icon {
         PLOT2_CUBE = makeIcon( "plot2cube.gif" ),
         PLOT2_SPHERE = makeIcon( "plot2sphere.gif" ),
         PLOT2_TIME = makeIcon( "plot2time.gif" ),
+        PLOT2_HISTOGRAM = makeIcon( "plot2hist.gif" ),
 
         /* Datanode (hierarchy browser) icons. */
         COLLAPSED = makeIcon( "handle1.gif" ),

topcat/src/main/uk/ac/starlink/topcat/plot2/HistogramPlotWindow.java

@@ -0,0 +1,79 @@
+package uk.ac.starlink.topcat.plot2;
+
+import java.awt.Component;
+import uk.ac.starlink.ttools.plot2.DataGeom;
+import uk.ac.starlink.ttools.plot2.PlotType;
+import uk.ac.starlink.ttools.plot2.Plotter;
+import uk.ac.starlink.ttools.plot2.SurfaceFactory;
+import uk.ac.starlink.ttools.plot2.geom.PlaneAspect;
+import uk.ac.starlink.ttools.plot2.geom.PlaneDataGeom;
+import uk.ac.starlink.ttools.plot2.geom.PlanePlotType;
+import uk.ac.starlink.ttools.plot2.geom.PlaneSurfaceFactory;
+import uk.ac.starlink.ttools.plot2.layer.FunctionPlotter;
+import uk.ac.starlink.ttools.plot2.layer.HistogramPlotter;
+import uk.ac.starlink.ttools.plot2.paper.PaperTypeSelector;
+
+/**
+ * Layer plot window for histograms.
+ * This is a slight variant of PlanePlotWindow, with a restricted set
+ * of plotters and modified axis controls.  It's here for convenience
+ * and easy start of a histogram - it is also possible to draw histograms
+ * in a normal plane plot.
+ *
+ * @author   Mark Taylor
+ * @since    21 Jan 2014
+ */
+public class HistogramPlotWindow
+             extends StackPlotWindow<PlaneSurfaceFactory.Profile,PlaneAspect> {
+    private static final PlotType PLOT_TYPE = new HistogramPlotType();
+    private static final PlotTypeGui PLOT_GUI = new HistogramPlotTypeGui();
+
+    /**
+     * Constructor.
+     *
+     * @param  parent  parent component
+     */
+    public HistogramPlotWindow( Component parent ) {
+        super( "Histo2", parent, PLOT_TYPE, PLOT_GUI );
+        addHelp( "HistogramPlotWindow" );
+    }
+
+    /**
+     * Variant of PlanePlotType for histograms; has a different set of plotters.
+     */
+    private static class HistogramPlotType implements PlotType {
+        private final PaperTypeSelector ptSelector_ =
+            PlanePlotType.getInstance().getPaperTypeSelector();
+        private final SurfaceFactory surfFact_ = new PlaneSurfaceFactory();
+        public PaperTypeSelector getPaperTypeSelector() {
+            return ptSelector_;
+        }
+        public DataGeom[] getPointDataGeoms() {
+            return new DataGeom[] { PlaneDataGeom.INSTANCE };
+        }
+        public SurfaceFactory getSurfaceFactory() {
+            return surfFact_;
+        }
+        public Plotter[] getPlotters() {
+            return new Plotter[] {
+                new HistogramPlotter( PlaneDataGeom.X_COORD, true ),
+                FunctionPlotter.PLANE,
+            };
+        }
+    }
+
+    /**
+     * Defines GUI features specific to histogram plot.
+     */
+    private static class HistogramPlotTypeGui
+            implements PlotTypeGui<PlaneSurfaceFactory.Profile,PlaneAspect> {
+        public AxisControl<PlaneSurfaceFactory.Profile,PlaneAspect>
+                createAxisControl( ControlStack stack ) {
+            return new PlaneAxisControl( stack );
+        }
+        public PositionCoordPanel createPositionCoordPanel( int npos ) {
+            return SimplePositionCoordPanel
+                  .createPanel( PLOT_TYPE.getPointDataGeoms()[ 0 ], npos );
+        }
+    }
+}