```Date: Feb 10, 2013 3:35 AM
Author: David Park
Subject: Re: Help with "recession bar" graph

Alan,All of which brings up a topic that confuses many users doing graphics.There are two kinds of Options that affect the look of a plot. The firstkind affect the drawn lines, curves, surfaces and primitives. Things such ascolor, shading, Mesh, PlotPoints and MaxRecursion. The second kind of Optionaffects the parts of the graphic that determine the overall look independentof the "drawn" items: such things as AspectRatio, ImageSize, Frame, Axis,Ticks, Background, PlotRegion, etc. There is at least one option, PlotRange,that may affect both aspects of the plot. For example, if you are combininga ContourPlot with other elements, you may need the z PlotRange to captureall of the contours, and the x and y ranges for the overall plot.With the Show statement Mathematica picks up the Options from the first plotin the Show statement and they override Options from subsequent plots. Thisdoesn't make a lot of sense and confuses many users. So, for example, if youhad an Epilog Option in the second plot that logically went with the secondplot, you would have to shift it to the first plot. However, you can alsoput Options at the end of the Show statement and these take precedence.So with Bob Hanlon's example:data = {38.396359394355414`, 72.27272309523107`, 89.29538328240793`,    72.10010639242938`, 82.58607698201098`, 18.6576446975194`,    33.27870983668225`, 21.4169865528564`, 27.143317794267958`,    56.831020645157224`, 97.91895556654552`, 53.699909198741835`,    62.45884842291329`, 43.57174038250221`, 5.572069539912178`,    47.64601720765782`, 57.36520060575606`, 11.616476185686125`,    53.621120873396194`, 86.51670206163143`, 46.158001732049314`,    91.79901697376656`, 56.56864196802621`, 68.80447171646065`,    69.71270226145879`, 9.193667545986898`, 12.322285539970679`,    84.54474541006726`, 37.46708245474912`, 70.19095794556748`,    21.368052894967576`, 95.70714721558335`, 19.184901239515995`,    12.369028572198587`, 97.66742717262244`, 64.70934352032668`,    1.1657357274066413`, 57.74269869413277`, 58.529638656649155`,    34.40274725318369`, 52.38021809465195`, 64.42731199035626`,    54.74507564841295`, 32.199884547032894`, 64.85420465012712`,    26.538659912812435`, 43.037739816388466`, 25.366295485189113`,    7.604466054852992`, 92.16216075731677`};Just add Options at the end, and here I give myself a tiny advantage by alsoadding some arrows to the graphic.Show[RegionPlot[{6 <= x <= 13, 19 <= x <= 25, 39 <= x <= 46}, {x, 0,    50}, {y, 0, 100}, BoundaryStyle -> None], ListLinePlot[data], Epilog ->  {Arrowheads[{-0.02, 0.02}], Arrow[{{6, 95}, {13, 95}}],    Arrow[{{19, 95}, {25, 95}}], Arrow[{{39, 95}, {46, 95}}]}, Frame -> False, AspectRatio -> 1/2, Axes -> True, ImageSize -> 400] With the Presentations Application this would be done as follows:<<Presentations` Draw2D[ {RegionDraw[{6 <= x <= 13, 19 <= x <= 25, 39 <= x <= 46}, {x, 0,     50}, {y, 0, 100}, BoundaryStyle -> None],  ListLineDraw[data],  Arrowheads[{-0.02, 0.02}],  Arrow[{{6, 95}, {13, 95}}], Arrow[{{19, 95}, {25, 95}}],   Arrow[{{39, 95}, {46, 95}}]},  AspectRatio -> 1/2, Axes -> True, ImageSize -> 400]Constructs such as RegionDraw and ListLineDraw do not take or use any of theoverall Graphics Options and they would show as Red if used. RegionDraw doesaccept BoundaryStyle because that affects the graphics primitives returned.We just draw one thing after another, including the Arrows, without havingto use Epilog or Graphics level jumping. The overall plot Options ALWAYS goat the end where we might expect them since they have nothing to do with theother items.David Parkdjmpark@comcast.net http://home.comcast.net/~djmpark/index.html   From: Alan G Isaac [mailto:alan.isaac@gmail.com] On 2/8/2013 11:12 AM, Bob Hanlon wrote:> Show[>   RegionPlot[>    {6 <= x <= 13, 19 <= x <= 25, 39 <= x <= 46},>    {x, 0, 50}, {y, 0, 100},>    BoundaryStyle -> None],>   ListLinePlot[data]]This is informative, but it does not meet my needs.You put the RegionPlot first, as needed for proper overlay, but then ithijacks the plot properties.I'm really looking for something equivalent to Matplotlib's axvspan, inorder to add a Graphics element to an existing plot.For now I'm putting a rectangle in the Prolog and handling the y-coordinatesmyself, but I'd welcome a better solution.Thanks,Alan Isaac
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