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<!-- $Id: news_body.part,v 1.16 2005/06/24 00:30:13 paultcochrane Exp $ --> |
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<h1>News</h1> |
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|
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<hr class="top" /> |
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<div class="item"> |
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<div class="itemTitle">Arrow plots possible in 3D</div> |
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<div class="itemDate">22-Jun-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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After some work on some other stuff I've finally managed to add |
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more functionality to pyvisi! This time one can do ArrowPlots in |
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three dimensions using vtk. The povray renderer module can also |
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be used to generate ArrowPlots, but work is still needed to get it |
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going nicely. It is also possible to use the vtk as well as the |
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gnuplot renderer modules to do 2D ArrowPlots. The new class is |
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called ArrowPlot3D, but may be changed to just ArrowPlot in |
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future, and one can let pyvisi work out which one you want to use. |
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</p> |
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<p> |
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There have been many other changes made as well, with a little |
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internal reorganisation of examples and a few other things, but |
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this is the main change of interest at present. |
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</p> |
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<p> |
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An example code has been added to the <code>examples/</code> |
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directory on the cvs and will be in the next distribution of the |
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package. It is called: |
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<ul> |
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<li><code>arrowPlot3D.py</code></li> |
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</ul> |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">Ball plots now available</div> |
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<div class="itemDate">19-Apr-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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It is now possible to create plots of spheres in space, i.e. |
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BallPlots. This at present is only possible with a vtk xml data |
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file. |
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</p> |
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<p> |
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An example code has been added to <code>examples/</code> directory on |
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the cvs and may be in the next distribution of the package. It is |
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called: |
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<ul> |
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<li><code>ballPlotExample.py</code></li> |
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</ul> |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">Movies from sequences of images</div> |
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<div class="itemDate">07-Mar-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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I've changed the internal way that objects are handled so that one |
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can now create sequences of images, and hence movies of functions |
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which change over the course of a simulation. This, however, has |
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made other parts of the interface slightly different, and one must |
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now call <code>setData()</code> just before each |
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<code>render()</code> or <code>save()</code> call, this I think |
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isn't very good and so this syntax requirement will be removed in |
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the future, when I get around to implementing the |
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<code>Renderer</code> object properly. Until then though, one is |
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able to make movies from the data! |
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</p> |
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<p> |
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Two new examples are in the <code>examples/</code> directory on |
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the cvs and will be in the next distribution of the package. They |
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are: |
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<ul> |
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<li><code>simplePlotMovieExample.py</code></li> |
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<li><code>contourPlotMovieExample.py</code></li> |
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</ul> |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">ArrowPlots available in gnuplot</div> |
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<div class="itemDate">07-Mar-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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I've added a very basic implementation of 2D vector field plots |
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for the gnuplot renderer module. Have a look at the new examples |
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in the pyvisi cvs (soon to be in the distribution): |
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<ul> |
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<li><code>arrowPlotExample.py</code></li> |
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<li><code>arrowPlotExample2.py</code></li> |
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</ul> |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">More plotting types added for gnuplot |
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renderer module</div> |
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<div class="itemDate">24-Feb-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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I've now been able to add many more kinds of plotting object to |
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the gnuplot renderer module. Now one can plot 2D contour maps of |
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3D data (see item from yesterday), one can plot 3D surfaces, |
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3D surfaces with a 2D projection of the surface contours onto the |
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base of the axes, and 2D and 3D scatter data (good to use when the |
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input data isn't on a grid). Extra examples have been added, |
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namely: |
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<ul> |
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<li><code>surfacePlotExample.py</code></li> |
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<li><code>surfaceAndContourPlotExample.py</code></li> |
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<li><code>scatterPlotExample.py</code></li> |
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<li><code>scatterPlot3DExample.py</code></li> |
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</ul> |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">Contour plotting works in gnuplot</div> |
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<div class="itemDate">23-Feb-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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Since objects can now render themselves, it was possible to |
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implement the different rendering code necessary for contour plots |
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to work in gnuplot. Have a look at the file |
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<code>contourPlotExample.py</code> in the <code>examples</code> |
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directory of the pyvisi cvs to see it in action. It is likely to |
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take a while to get the vtk version going, but it will come in the |
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fullness of time. |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">Objects render themselves</div> |
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<div class="itemDate">23-Feb-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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Objects now render themselves. Therefore, there is no longer a |
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reason to call the <code>render()</code> method of a scene's |
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sub-object directly; this is taken care of when the |
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<code>render()</code> method of the scene is called. The example |
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code has been changed in the cvs, and so look for the updated |
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versions of the examples in the second release of the pre-alpha |
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version of pyvisi. |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">First release of pre-alpha version of pyvisi</div> |
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<div class="itemDate">08-Feb-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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After much cleaning of the code with the help of <a |
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href="http://pylint.sourceforge.net">pylint</a>, and updating |
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READMEs and stuff, I've released the first pre-alpha version of |
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pyvisi. This is a very limited functionality version, but is |
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something for people to see how things will look, and for me to |
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get some kind of feedback from people to how they would like it to |
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look and behave. There are three examples that work at present, |
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these are <code>simplePlotExample.py</code>, |
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<code>singleArrayPlotExample.py</code>, and |
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<code>multiPlotExample.py</code>. These examples show the current |
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functionality possible with pyvisi, and what the gnuplot and vtk |
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equivalent code is. |
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</p> |
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<p> |
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<strong>Download</strong>: you can download pyvisi from the |
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sourceforge.net web site by visiting <a |
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href="http://sourceforge.net/project/showfiles.php?group_id=124511">pyvisi download files page</a> |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">Scenes can now be saved to file</div> |
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<div class="itemDate">24-Jan-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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It is now possible to save the scenes that you have rendered! |
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Previously, scenes were displayed to the screen and that was all, |
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however now the <code>Scene.save()</code> method has been |
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implemented in both the <a |
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href="http://www.gnuplot.info">gnuplot</a> and <a |
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href="http://www.vtk.org">vtk</a> renderer modules. The |
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syntax of the <code>save()</code> method will change (in that the |
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<code>format</code> argument will become an object), nevertheless, |
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one is now actually able to save one's work. |
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</p> |
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<p> |
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The gnuplot renderer module can handle png and postscript output |
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at present. With gnuplot 4.0 more output formats will be |
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available. |
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</p> |
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<p> |
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The vtk renderer module can handle png, postscript, jpeg, bmp, |
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pnm, and tiff formats. |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">Multiple curves on 2D plots are now possible</div> |
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<div class="itemDate">24-Jan-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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Pyvisi now supports plotting multiple datasets when graphing 2D |
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curves. To plot more than one curve on a given |
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<code>LinePlot</code>, one uses the syntax: <code>plot.setData(x, |
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y1, y2, y3, ...)</code>. The first element in the argument |
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list is assumed to the x data to plot the subsequent arrays |
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against, except in the case that there is only one array in the |
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argument list, in which case the x data is autogenerated as the |
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indices (starting from 1 (maybe this should be zero??)) of the |
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argument data array. |
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</p> |
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<p> |
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To have a look at multiple curves in action, have a look at |
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<code>multiCurvePlotExample.py</code> in the |
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<code>examples/</code> directory of the pyvisi distribution. |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">Simple 2D contour plotting not far away</div> |
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<div class="itemDate">24-Jan-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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Implementing simple contour plotting with just the <a |
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href="http://www.gnuplot.info">gnuplot</a> renderer module has |
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shown a couple of major holes that need plugging. The main |
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problem at present is that gnuplot requires a call to the |
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<code>splot</code> command to plot contours and surfaces, but a |
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call to the <code>plot</code> command to plot simple 2D graphs. |
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Unfortunately, the call to plot the relevant graph is handled by |
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the <code>render()</code> method within the <code>Scene</code> |
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object, and consequently is just the <code>plot</code> command, |
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which means that this is the wrong place for the object-specific |
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rendering commands, and that the <code>Scene.render()</code> |
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method should call the <code>render()</code> methods of the |
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objects within the scene to do all of the rendering hard work. |
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This may take a while to implement, but things will be more |
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flexible in the future as a result. |
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</p> |
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<p> |
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One of the other major problems that will need to be seen to is |
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the sharing of data objects with the module actually doing the |
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rendering and the pyvisi code actually being run by the user. |
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There are many elements to work on here. Essentially, we need to |
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put the <code>Renderer</code> object into a separate <a |
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href="http://www.python.org">python</a> process or thread, and |
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then open a pipe to the process and pass commands and objects |
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through to it. This will sort of solve two problems |
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simultaneously as we need a separate thread/process for the |
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<code>Renderer</code> object anyway, and this may be the best way |
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to share data objects around. At present, I have implemented a |
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really dodgy way of passing the data around which isn't scalable, |
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but it managed to get the simple 2D plotting to go. Again, this |
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may take a while... |
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</p> |
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</div> |
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</div> |
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|
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<div class="item"> |
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<div class="itemTitle">Simple 2D plotting works!</div> |
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<div class="itemDate">18-Jan-2005</div> |
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<div class="itemAuthor">Paul Cochrane</div> |
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|
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<div class="itemText"> |
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<p> |
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Simple 2D plotting works in both <a |
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href="http://www.vtk.org/">vtk</a> |
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*and* <a href="http://www.gnuplot.info/">gnuplot</a>!! This |
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certainly felt like a major achievement, as it wasn't easy to get |
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vtk to do 2D x-y plots. To get a feeling for what I've done check |
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out <code>plotExample.py</code> in the <code>examples</code> |
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directory of the <a href="http://pyvisi.sourceforge.net">pyvisi</a> |
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distribution. |
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</p> |
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<p> |
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Please note that this is <strong>very</strong> basic. At present |
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one can only plot one set of data, and the way the data is |
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transferred to the renderer module in the backend is very |
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simplistic and not amenable to scaling to large datasets. |
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Nevertheless, this example shows how pyvisi can be used in the |
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future. It is also only possible to pass to the plotting routines |
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two 1D arrays of data, one for the x-axis and one for the y-axis. |
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Also, there isn't any implementation yet for changing colour on |
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the axes, or the plot lines, however there is limited functionality |
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available for choosing different kinds of linestyles. I'm also |
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not completely happy with the syntax at the user-level of the |
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interface, and this has to change. Specifically, the |
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<code>.add()</code> method of the scene object to add an object |
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to the scene. Surely this should be sorted out when one |
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instantiates the object and passes the scene object as an |
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argument. The other method that needs to disappear from user-space |
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is the <code>.render()</code> method of the individual objects. |
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Users should only have to render the scene. The problem here is |
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to finish off some stuff that vtk needs before doing the final |
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render (such as the <code>AddActor()</code> methods); this can be |
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done a better way. One problem with the way I'm doing it at |
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present is that re-rendering *doesn't* need the pre-render step. |
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But re-rendering is a different kettle of fish, and there are |
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many other things to work on before we get to there. |
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</p> |
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<p> |
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Note that to use the vtk renderer module, you must have vtk |
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installed, and have configured vtk for python (so that the python |
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vtk wrappers are available). To use the gnuplot renderer module, |
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you must have gnuplot (version greater than or equal to 3.7) |
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installed, and <a |
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href="http://gnuplot-py.sourceforge.net/">Gnuplot.py</a> (the |
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gnuplot python wrapper). |
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</p> |
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<p> |
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Even with all of these caveats, have a look at the example code, |
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and tell me if you like the syntax (or not), if you have any |
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comments or suggestions as to what I could do extra or what I |
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could do differently, or even if you were able to get the |
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<code>plotExample.py</code> example to go! |
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</p> |
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</div> |
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</div> |
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