DMelt:Plots/3 Custom Plots
Custom plots in 2D
You can create fully custom plots with arbitrary layouts by writing Jython and Java code and accessing internal methods.
First, let us consider a simple plots based on the class 
jhplot.HPlotXY.
Using the method "getPlot()" of this class one can return a plot object of the Plot class that can be changed using an arbitrary layout. Let us consider a simple example:
The output plots is:
You can see that jhplot.HPlotXY is very similar to jhplot.HPlot. However, it has several features that can help to build non-standard layouts.
In order to access all such plotting zones, you can look at the following methods:
c1=HPlotXY("Cosmology",600,700,0)
c1.visible()
ef=c1.getFactory()
plot=c1.getPlot()
env=c1.Env()
The function "getFactory()" returns class, while getPlot() returns the actual plotting area. Look at the API of these classes:
The ElementFactory class cab be used to create axis, titles, legends and subplots.
In order to export plots to one of the vector-graphics formats supported by dmelt, use the usual method:
c1.export("image.svg")
(change the extension to use different file format).
Now let us build an example that shows a plot with two subplots, custom title and data points with the legends.
The output image created by the above code is:
Building titles
After you create the "plot" object of the class
org.jplot2d.element.Plot and "ef" factory object using
org.jplot2d.element.ElementFactory class, you can add a title as:
from org.jplot2d.element import *
title = ef.createTitle("Custom Title")
title.setFontScale(2)
plot.addTitle(title)
The "title" object belongs to org.jplot2d.element.Title class.
You can use TeX-like formatting of strings in plots. Entering math mode using a "dollar" symbol it is possible to insert Greek characters, for instance using
\\alpha - greek alpha \\beta - greek beta
{| class="wikitable sortable" border=1
! # superscript symbol
|-
|}
_ # subscript symbol
Here is how to show math:
text="$A_{1.3}^{b-3/2}$"
text="$\\alpha_{1.3}^{\\beta-3/2}$"
The following special symbols are available:
- All the lower-case Greek letters.
- The following upper-case Greek letters: \Gamma, \Delta, \Theta, \Lambda, \Xi, \Pi, \Sigma, \Upsilon, \Phi, \Psi, \Omega .
- The \angstrom and \micro symbols.
To insert other symbols you can use the Unicode escape sequence \uxxxx , where xxxx is the hexadecimal code of the symbol. For example, \u2299 corresponds to the circle dot operator, which can also be used as symbol for the Sun. Use [1] table to look at how to map unicode characters.
Creating Axes
To create axised for X and Y, use "createAxis" method of
"ef" factory object of
org.jplot2d.element.ElementFactory class
xaxis = ef.createAxis(); yaxis = ef.createAxis(); # setting an axis transform to LOGARITHMIC xaxis.getTickManager().getAxisTransform().setTransform(TransformType.LOGARITHMIC);
The objects "xaxis" and "yaxis" belong to Axis class.
To add an axis to the plot, use these methds:
plot.addXAxis(xaxis) plot.addYAxis(yaxis)
You may want 2 x-axes and 2 y-axes to box the plot contents. In this case, 2 x-axes or y-axes can be created and added together. The created 2 x-axes share the same tickManager. And so the 2 y-axes.
xaxes = ef.createAxes(2) yaxes = ef.createAxes(2) # setting an axis transform to LOGARITHMIC xaxes[0].getTickManager().getAxisTransform().setTransform(TransformType.LOGARITHMIC); plot.addXAxes(xaxes) # add them to the plot plot.addYAxes(yaxes)
Let us show how to make titles, subtitles and axes in this example:
The resulting plot is:
Creating layers
A layer can associate with a x-axis and a y-axis, i.e. it is associated with a x AxisTransform and a y AxisTrasform. When adding a layer to a plot, the associated x AxisTransform and y AxisTrasform must be given as arguments, and they must already exist in the plot (by adding the x axis and y axis object).
layer = ef.createLayer(); # The xaxis and yaxis must has been added to the plot plot.addLayer(layer, xaxis.getTickManager().getAxisTransform(), yaxis.getTickManager().getAxisTransform())
The "layer" object belongs to the org.jplot2d.element.Layer class.
You can extract layers from the plots as:
layers = plot.getLayers()
Creating Graphs
A 2d graph can be created with 2 double array
from array import *
x = array('d',[0,1,2,3])
y = array('d',[0,2,1,4])
graph = ef.createXYGraph(x, y)
layer.addGraph(graph) # add this graph to layer
Similarly, your code in Java will look as:
double[] x = new double[] {0,1,2,3};
double[] y = new double[] {0,2,1,4};
XYGraph graph = ef.createXYGraph(x, y);
layer.addGraph(graph) # add this graph to layer
The "layer" object belongs to the org.jplot2d.element.XYGraph class.
You can customize the graph using the methods:
graph.setColor(Color.GREEN); graph.setLineVisible(False); graph.setSymbolVisible(True); graph.setSymbolShape(SymbolShape.SQUARE);
Look at the org.jplot2d.element.XYGraph class.
See the org.jplot2d.util.SymbolShape class.
Data points can have errors bars in X and Y. Create a XYGraph with the given x/y array, x low/high error array and y low/high error array, use this method:
graph=ef.createXYGraph(x_array, y_array, xErrorLow, xErrorHigh, yErrorLow, yErrorHigh, name)
Creating Annotations
There are several kind of annotations can be created
- symbol annotation A point annotation with a symbol and a text string
- horizontal line annotation A horizontal line annotation to highlight a value.
- vertical line annotation A vertical line annotation to highlight a value.
- horizontal strip annotation A horizontal strip annotation to highlight a range.
- vertical strip annotation A vertical strip annotation to highlight a range.
- rectangle annotation A rectangle annotation to highlight a area.
The "annotations" objects belong to the org.jplot2d.element.Annotation class.
Look at how the annotations can be made:
ann0 = ef.createSymbolAnnotation(x, y, "text annotation") # symbol annotation ann1 = ef.createHLineAnnotation(y) # horizontal line annotation ann2 = ef.createHStripAnnotation(y1, y2) # horizontal strip annotation layer.addAnnotation(annotation) # Adding an annotation to a layer
