com.davisor.graphics.chart
Class HexGridFactory

java.lang.Object
  com.davisor.graphics.chart.ChartFactory
      com.davisor.graphics.chart.AxisFactory
          com.davisor.graphics.chart.GridFactory
              com.davisor.graphics.chart.HexGridFactory

All Implemented Interfaces:

com.davisor.core.Dupable, com.davisor.core.MIMETypes, com.davisor.core.Public

public class HexGridFactory

extends GridFactory

HexGridFactory implements a grid chart filled with hexagonal cells. The hexagons stand on one of their vertices, and they are arranged into rectangular grid as shown below.

                          |--| margin
                               -
        .     .     .     .    |
      ..:..^..:..^..:..^..:... -
        :/   \:/   \:/   \:
    2   |     |     |     |
        |     |     |     |
      ..:\....^.....^..../:...
        : \ / : \ / : \ / : \ 
    1   :  Y  :  Y  :  Y  :  |
        :  |  :  |  :  |  :  |
 -    ..:..^..:..^..:..^..:./.
 |      :/   \:/   \:/   \:/
 1  0   |     Y     Y     Y
 |      |     |     |     |
 -    ..:\.../:\.../:\.../:... -
        : `v' : `v' : `v' :    |
                               -
           0     1     2  |--| margin

        |--1--|
 

Laying hexagons on rectangular grid raises some difficult problems. First, hexagon natural cell coordinates where axes are in 60 degreen angle must be mapped to rectangular cell coordinates where the axes are in 90 angle. Second, hexagon natural 60-degree symmetric unit radius must be mapped on corresponding uneven horizontal and vertical radiuses. Finally, when laid out on a rectangular grid, some extra margin space is needed around the outer edge of the grid to make room for the uneven hexagon boundary line that exceeds the boundaries of corresponding rectangular grid.

The cell coordinate problem may be solved by shifing hexagon rows left so that cells with equal X coordinates lie in straigh columns, within the limitations set by hexagonal topology of course. When map is zoomed in by dividing hexagons into smaller hexagons, the shifting pattern becomes more complex:

         /\    /\     ::
        /  \  /\/\   ::::
       /\  / /\/\/  :::::
      /  \/ /\/\/  :::::
      \  /\ \/\/\  :::::
       \/  \ \/\/\  :::::
       /\  / /\/\/  :::::
      /  \/ /\/\/  :::::
      \  /  \/\/   ::::
       \/    \/     ::
 level: 1     2     3     ...
 

The Y -axis step value controls the zooming level, and therefore also the number of rows that are shifted to the same direction at a time.

The second problem is solved by first using a hexagon radius R that makes the hexagons one unit step wide, and then scaling the hexagons vertically by 1/A so that the vertical distance between hexagon rows becomes also one unit step high. The resulting distoted hexagon is no more symmetric along the hexagon natural 60-degreen angles, but it is symmetric horizontally and vertically. The createHexagon(float, float) method provides a tool to create such hexagon shapes.

Thanks to the vertical scaling, the bounding box of the distorted unit hexagon exceeds vertial unit size. The hexagons will not however cover each other as the hexagon rows interleave in the way hexagons do, but on the bottom and top boundaries of such a hexagon map, extra space is needed or the outer tips of the edgemost hexagons will be clipped of. The amoun of this extra space can be computed with the computeHexagonMargin(int, float, float, int) method.

Since:

JDK1.2

Nested Class Summary

Nested classes inherited from class com.davisor.graphics.chart.AxisFactory

AxisFactory.AxisContext, AxisFactory.AxisMetrics

Nested classes inherited from class com.davisor.graphics.chart.ChartFactory

ChartFactory.ChartContext, ChartFactory.ChartMetrics

Field Summary

protected static float	A
protected static float	C
protected static java.awt.geom.GeneralPath	HEXAGON
protected static float	R
protected static float	RX
protected static float	RY

Fields inherited from class com.davisor.graphics.chart.AxisFactory

DEFAULTLABELTYPE, FLIPX, FLIPY, MAJORMARGIN, MINORMARGIN, MINSIZE

Fields inherited from class com.davisor.graphics.chart.ChartFactory

ALL, BRIGHT, CHANNEL, COS, DARK, DOTSEQUENCE, DOTSTROKE, DOTSTROKEWIDTH, DUMPFACTORYNAME, ENCODERINFO, FONT, FRC, HAS_3D, I, LABEL, LABELFIELDNAMES, LABELFIELDS, MIME_DEFAULT, NONE, NORMAL, NULLSTROKE, PERCENT, PI2, SHAPE, SIN, STROKE, STROKEWIDTH, TIC, VALUE, X, Y, Z

Fields inherited from interface com.davisor.core.MIMETypes

FILETYPE_BMP, FILETYPE_CSS, FILETYPE_DOC, FILETYPE_ECMA, FILETYPE_GIF, FILETYPE_HTML, FILETYPE_HTML_CSS, FILETYPE_INDEX, FILETYPE_INDEX_DOC, FILETYPE_INDEX_HTML, FILETYPE_INDEX_HTML_CSS, FILETYPE_INDEX_PDF, FILETYPE_INDEX_PPT, FILETYPE_INDEX_SVG, FILETYPE_INDEX_XHTML, FILETYPE_INDEX_XLS, FILETYPE_INDEX_XMSE, FILETYPE_INDEX_XMSP, FILETYPE_INDEX_XMSW, FILETYPE_INDEX_XSLFO, FILETYPE_JPEG, FILETYPE_PDF, FILETYPE_PNG, FILETYPE_PNG_WBMP, FILETYPE_PPM, FILETYPE_PPT, FILETYPE_SVG, FILETYPE_TEXT, FILETYPE_WBMP, FILETYPE_XHTML, FILETYPE_XLS, FILETYPE_XML, FILETYPE_XMSE, FILETYPE_XMSP, FILETYPE_XMSW, FILETYPE_XSLFO, FILETYPE_XSLFO_CSS, MIME_BMP, MIME_CSS, MIME_DOC, MIME_ECMA, MIME_GIF, MIME_HTML, MIME_HTML_CSS, MIME_INDEX, MIME_INDEX_DOC, MIME_INDEX_HTML, MIME_INDEX_HTML_CSS, MIME_INDEX_PDF, MIME_INDEX_PPT, MIME_INDEX_SVG, MIME_INDEX_XHTML, MIME_INDEX_XLS, MIME_INDEX_XMSE, MIME_INDEX_XMSP, MIME_INDEX_XMSW, MIME_INDEX_XSLFO, MIME_JPEG, MIME_OTHER, MIME_PDF, MIME_PNG, MIME_PNG_WBMP, MIME_PPM, MIME_PPT, MIME_SVG, MIME_TEXT, MIME_WBMP, MIME_XHTML, MIME_XLS, MIME_XML, MIME_XMSE, MIME_XMSP, MIME_XMSW, MIME_XSLFO, MIME_XSLFO_CSS

Constructor Summary

HexGridFactory()
Default constructor.

HexGridFactory(GridFactory factory)
Copy constructor.

Method Summary

static float[]	computeHexagonMargin(int dim, float size, float steps, int level) Computes how much margin space the edgemost hexagons in a fixed size hexagonal grid need around them, and what would the cell size then be.
protected java.awt.Shape	createCellShape(java.awt.geom.Rectangle2D drawingArea, int[] steps, int level) Creates a new hexagon grid element shape object scaled to fill a cell of given size.
static java.awt.Shape	createHexagon(float width, float height) Creates a new hexagon shape object scaled to "fill" a cell of given size.
protected Chart	drawChart(AxisFactory.AxisContext context, AxisFactory.AxisMetrics metrics, ChartAxes axes, boolean fillGrid, boolean drawAxes, boolean drawLabel, boolean drawGrid, Chart chart, int[] steps, int level) Creates a grid chart.
com.davisor.core.Dupable	dup() Makes a deep copy of this object.
protected java.awt.geom.Point2D	getCellPoint(int x, int y, java.awt.geom.Rectangle2D drawingArea, int[] steps, int level) Computes the coordinates of the centermost point of the hexagon [x,y].

Methods inherited from class com.davisor.graphics.chart.GridFactory

drawCells, drawChart, drawLabels, getIdealSize, resolveLimits

Methods inherited from class com.davisor.graphics.chart.AxisFactory

computeMinorMargin, createChart, createChart, createContext, createContext, createContext, createContext, createMetrics, createMetrics, createMetrics, createMetrics, drawAxis, drawMarkers, drawTics, drawXYAxes, drawXYZAxes, fillGrid, fillMarkers, formatDouble, getIdealSize, hasGridLines, isSilent, labelAxis, labelMarkers, resolveLabels, resolveLabels, resolveMarkerSizes, resolveOverlap, titleAxis, transpose

Methods inherited from class com.davisor.graphics.chart.ChartFactory

annotate, combineProperties, createChannelType, createChannelType, createChart, createChart, createChart, createChart, createChart, createFormat, createPaintChannelType, createPaintChannelType, createShapeChannelType, createShapeChannelType, createSummary, drawLabel, getContentType, getDefaultPaint, getFactory, getFactory, getGroup, getIsometricCoefficients, getLegendShape, getName, has3D, hasSVG, isClassAvailable, isMultiSeriesMode, main, mayHaveLegend, registerFactory, resolveDataLimits, resolveDataLimits, rotateSize, shade, unregisterFactory

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

A

protected static final float A

R

protected static final float R

C

protected static final float C

RX

protected static final float RX

RY

protected static final float RY

HEXAGON

protected static final java.awt.geom.GeneralPath HEXAGON

Constructor Detail

HexGridFactory

public HexGridFactory()

Default constructor.

HexGridFactory

public HexGridFactory(GridFactory factory)

Copy constructor.

Method Detail

drawChart

protected Chart drawChart(AxisFactory.AxisContext context,
                          AxisFactory.AxisMetrics metrics,
                          ChartAxes axes,
                          boolean fillGrid,
                          boolean drawAxes,
                          boolean drawLabel,
                          boolean drawGrid,
                          Chart chart,
                          int[] steps,
                          int level)
                   throws InvalidDataException

Creates a grid chart.

This method allocate plot offset margins for hexagon top and bottom spikes and for horizontally shifted rows, and then invokes corresponding superclass method to do the actual drawing.

Overrides:

drawChart in class GridFactory

Parameters:

context - chart context

metrics - chart metrics

axes - chart axes

fillGrid - enables or disables axis background filling

drawAxes - determine which axes may be drawn

drawLabel - determine if default labeling is to be applied

drawGrid - determine if axis grid is to be drawn

chart - chart to draw into

steps - number of grid elements

level - grid zoom level

Throws:

InvalidDataException - if data is invalid for chart drawing

See Also:

computeHexagonMargin(int, float, float, int), AxisFactory.AxisMetrics.setPlotOffset(int,float)

dup

public com.davisor.core.Dupable dup()
                             throws com.davisor.core.DupNotSupportedError

Makes a deep copy of this object.

Throws:

com.davisor.core.DupNotSupportedError - if the object cannot be deep-copied

createCellShape

protected java.awt.Shape createCellShape(java.awt.geom.Rectangle2D drawingArea,
                                         int[] steps,
                                         int level)

Creates a new hexagon grid element shape object scaled to fill a cell of given size.

Specified by:

createCellShape in class GridFactory

Parameters:

drawingArea - area where cells will be drawn

steps - number of cell layers

level - zooming level

See Also:

createHexagon(float, float)

getCellPoint

protected java.awt.geom.Point2D getCellPoint(int x,
                                             int y,
                                             java.awt.geom.Rectangle2D drawingArea,
                                             int[] steps,
                                             int level)

Computes the coordinates of the centermost point of the hexagon [x,y].

This method assumes that enough margin space has been reserved outside the hexagon cells, as described by computeHexagonMargin(int, float, float, int).

Specified by:

getCellPoint in class GridFactory

Parameters:

x - cell x coordinate

y - cell y coordinate

drawingArea - area where cells will be drawn

steps - number of cells

level - zooming level

computeHexagonMargin

public static float[] computeHexagonMargin(int dim,
                                           float size,
                                           float steps,
                                           int level)

Computes how much margin space the edgemost hexagons in a fixed size hexagonal grid need around them, and what would the cell size then be.

       cellsize
          : : 
 offset/2 : : offset/2
      . . : : . .
  ___ :_:_:_:_:_:..
   |  | :.....:.|.. offset/2
   |  | :.:.:.: |..........
 size | :.:.:.: |.......... cellsize
   |  | :.:.:.:.|..
  _|_ |_________|.. offset/2
    
      |--size---|

  

In particular, with the number of steps and the amount of available space known, this method solves to following equations for 'offset' and 'cellsize':

 steps * cellsize + offset = size
                    aspect = offset/cellsize

         horizontal aspect = level * 0.5 
           vertical aspect = C
 

Parameters:

dim - width/height dimension selector

size - grid size along the given dimension

steps - the number of grid cells along the given dimension

level - zooming level

Returns:

[offset,cellsize]

createHexagon

public static java.awt.Shape createHexagon(float width,
                                           float height)

Creates a new hexagon shape object scaled to "fill" a cell of given size. The returned shape will be a hexagon standing on it's tip, with points running in clockwise direction.

A hexagon that stands on it's tip and that that "fills" a cell must exceed it's rectangular boundaries as follows:

   ........... -
 - ..:..^..:.. |
 |   :/   \:   |           _____
 1   |     |  1/A     A = V 3/4
 |   |     |   |          
 - ..:\.../:.. |
   ..:..v..:.. -

     |--1--|
 

The returned shape will therefore meet given width exactly, but be 1/A times taller than requested. The origo of the shape will be at it's center.

Parameters:

width - cell width

height - cell height

Returns:

new hexagon shape, as described above