Re: Flat colour in RegionPlot; millions of little triangles

*To*: mathgroup at smc.vnet.net*Subject*: [mg81712] Re: Flat colour in RegionPlot; millions of little triangles*From*: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>*Date*: Tue, 2 Oct 2007 05:32:59 -0400 (EDT)*Organization*: The Open University, Milton Keynes, UK*References*: <fdkqst$7bk$1@smc.vnet.net> <46FDF56B.5070106@gmail.com> <fdl9e7$d1p$1@smc.vnet.net>

Will Robertson wrote: > Hi Jean-Marc, > > Thanks for the reply. > > On 29/09/2007, at 16:19 , Jean-Marc Gulliet wrote: >> Could you be more precise about the size of the exported files >> (before and after manual fixing) and about what size you expect and = > >> deem as reasonable? > > Sure, the example I posted is not particularly large or complex (but > it does demonstrate the problem). When calculating RegionPlot with a > troublesome function that requires a very tight mesh, however, the > problem is much worse. (Displaying the PDF in Acrobat Reader is > visibly delayed as it stops to draw every single blue polygon.) > > I can't test out a more complicated example until I get back to my > office but you might find that this produces a more troublesome PDF: > ContourPlot[Sin[x y],{x,=E2=88=925,5},{y,=E2=88=925,5}] Hi Will, In version 6, the quality of a plot depends on the value of some new options such as *MaxRecursion* (my understanding is that this option controls the behavior of the new adaptative sampling algorithm) and also *PlotPoints*. Below you will find sizes of pdf files created from *ContourPlot* with various settings of *MaxRecursion* and *PlotPoints*. Using the default values, we can see that the pdf file is about 1.5 Mb, whereas, setting *MaxRecursion* to 0, the size is about 72 Kb, i.e 21 times less. Now, look at the quality (aesthetic) of the graph in both cases: the differences ares striking and the visual appearance of the former graph is so poor that it looks like it has not been produced by the same application (at least to my eyes :-) You can find the evaluated notebook and a pdf version at http://homepages.nyu.edu/~jmg336/mathematica/contour-plot.pdf http://homepages.nyu.edu/~jmg336/mathematica/contour-plot.nb In[1]:= $Version Out[1]= "6.0 for Microsoft Windows (32-bit) (June 19, 2007)" In[2]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5}, PlotLabel -> "MaxRecursion->Automatic\nPlotPoins->Automatic"] Export["contour-plot.pdf", %]; ByteCount /. FileInformation[%] Out[4]= 1535524 In[5]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5}, MaxRecursion -> 0, PlotLabel -> "MaxRecursion->0\nPlotPoins->Automatic"] Export["contour-plot.pdf", %]; ByteCount /. FileInformation[%] Out[7]= 72915 In[8]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5}, MaxRecursion -> 1, PlotLabel -> "MaxRecursion->0\nPlotPoins->Automatic"] Export["contour-plot.pdf", %]; ByteCount /. FileInformation[%] Out[10]= 321697 In[11]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5}, MaxRecursion -> 2, PlotLabel -> "MaxRecursion->2\nPlotPoins->Automatic"] Export["contour-plot.pdf", %]; ByteCount /. FileInformation[%] Out[13]= 1535522 In[14]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5}, MaxRecursion -> 2, PlotPoints -> 5, PlotLabel -> "MaxRecursion->2\nPlotPoins->5"] Export["contour-plot.pdf", %]; ByteCount /. FileInformation[%] Out[16]= 214543 In[17]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5}, MaxRecursion -> 2, PlotPoints -> 6, PlotLabel -> "MaxRecursion->2\nPlotPoins->6"] Export["contour-plot.pdf", %]; ByteCount /. FileInformation[%] Out[19]= 509790 In[20]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5}, MaxRecursion -> 2, PlotPoints -> 7, PlotLabel -> "MaxRecursion->2\nPlotPoins->7"] Export["contour-plot.pdf", %]; ByteCount /. FileInformation[%] Out[22]= 602774 In[23]:= ContourPlot[Sin[x y], {x, -5, 5}, {y, -5, 5}, MaxRecursion -> 2, PlotPoints -> 10, PlotLabel -> "MaxRecursion->2\nPlotPoins->10"] Export["contour-plot.pdf", %]; ByteCount /. FileInformation[%] Out[25]= 905323 Regards, -- Jean-Marc