View source for DMelt:Plots/4 Showing 2D Shapes

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= Simple 2D shapes =

In addition to data, histograms, functions, <javadoc>jhplot.HPlot</javadoc> canvas can show arbitrary shapes (boxes, text, images, arrows) in the user ("USER") coordinates (i.e. given by the axis values) or in the absolute coordinates ("NDC").
You can mix data and shapes in arbitrary order.

The following shapes can be plotted:
 
*     <javadoc>jhplot.shapes.Arrow</javadoc> - Arrow
*     <javadoc>jhplot.shapes.Circle</javadoc> - Circle
*     <javadoc>jhplot.shapes.Ellipse</javadoc> - Ellipse
*     <javadoc>jhplot.shapes.Line</javadoc> - Line
*     <javadoc>jhplot.shapes.Picture</javadoc> - Picture (in PNG or JPG formats)
*     <javadoc>jhplot.shapes.Rectan</javadoc>  - Rectangle 
*     <javadoc>jhplot.shapes.Text</javadoc> - Simple (not interactive) text


You should also remember that you can always draw shapes with data points. Here is an example how to  draw an ellipse
with semi-major (longest radius)  and semi-minor (shortest radius) radii:

<jput>
image 778283
</jput>

Here is a simple code to do this:

<jcode lang="python">
dmelt 778283.py
</jcode>

You can convert it to Groovy or Java code  using the same logic. Decrease the step size to obtain a smooth line.

Now let us construct rotated ellipse by some angle and overlay it with a 2D Ellipse using "2D" shape approach:

<jput>
image 21778374
</jput>

The code to generate this image is below:

<ifauth !@member>
<jcode lang="python">
dmelt 21778374.py
</jcode>
</ifauth>

Finally, one can generate random data points following the ellipse shape. We will use parametric description of the ellipse, rotate it and generate random numbers:

<jput>
image 86778365
</jput>

The Python code this image is below:

<ifauth>
<jcode lang="python">
dmelt 86778365.py
</jcode>
</ifauth>

You can use the basic 2D primitives to draw shapes.
Here is a simple example how to draw such shapes:

<jput>
image 30155238
</jput>

You can find a script that generates this image below. It shows how to add X-Y data, histograms a then draw simple 2D graphic primitives on the top:

<ifauth>
<jcode lang="python">
code 30155238.py
</jcode>


Always use "add" method to add the shape to the canvas. When you draw data, (calling "draw()" method), this will update
the canvas. Or, you can use "c1.update()" method to trigger the update.

In the above example, we use "USER" coordinates. If you want to plot a shape in coordinate system independent of the axis, use "NDC" coordinates (values run from 0 to 1).

Please look at the package <javadoc>jhplot.shapes.HShape</javadoc> that is used to build such shapes.

</ifauth>

[[Category:Statistical charts and diagrams]]
[[Category:Plots]]