How do I get text to rotate correctly? - wolfram-mathematica

I can never seem to get text to rotate correctly inside a plot, whereas the same text rotates perfectly otherwise. For example,
Plot[Sin[x], {x, -2 Pi, 2 Pi},
Epilog ->
First#Graphics[Rotate[Text["Sine", {Pi, 1/2}], -30 Degree]]]
gives the following.
The text is skewed and hardly legible. How do I rotate the text correctly?

The skewing happens because the text is directly included and the scale of the two axis is not the same. If you set AspectRatio to Automatic the scale will be the same and the text is readable:
Plot[Sin[x], {x, -2 Pi, 2 Pi},
Epilog -> First#Graphics[Rotate[Text["Sine", {Pi, 1/2}], -30 Degree]],
AspectRatio -> Automatic
]
To keep the aspect ratio (which is probably what you want), wrap the text in Inset:
Plot[Sin[x], {x, -2 Pi, 2 Pi},
Epilog -> Inset[Rotate[Text["Sine"], -70 Degree], {Pi, 1/2}]
]

You can also move the Rotate inside the Text:
Plot[Sin[x], {x, -2 Pi, 2 Pi},
Epilog -> Text[Rotate["Sine", -70 Degree], {Pi, 1/2}]]
which will also avoid the skewing from the aspect ratio.

Related

How to generate function name automatically in mathematica?

When I draw multiple functions like exp,2^x,3^x, is it possible to generate a label of each function?
My code now:
Plot[{Exp[x], 2^x, 3^x}, {x, -5, 2}, AspectRatio -> Automatic, PlotStyle -> {Red, Green, Blue}]
What I mean is generate 3 labels in this case to tell the user what function it is.
Such as:
How do you generate this?
Perhaps this works: Use Tooltip in Plot to generate a Graphics object with tooltips. Then rewrite the tooltip to place the desired text in the desired location:
Plot[
Tooltip#{Exp[x], 2^x, 3^x}, {x, -5, 2},
AspectRatio -> Automatic,
PlotStyle -> {Red, Green, Blue},
PlotRange -> All,
PlotRangePadding -> 1.1] /.
{
Tooltip[{_, color_, line_}, tip_]
:>
{Text[Style[tip, 14], {.25, 0} + line[[1, -1]]], color, line}
}
I am not sure what the rules are for adding another, different answer for the same question. But here is another, different way to do it. If I am supposed to add this to my first answer, I can do that.
You can add the text labels, by hand, using Text commands. I think it looks better. Here is one way:
Clear[x];
funs = {Exp[x], 2^x, 3^x};
funNames = Style[#, 12] & /# funs;
(*the x-axis plot range used *)
from = -5; to = 2;
(* generate the coordinates at the end of the plot lines*)
pos = Map[{to, #} &, funs /. x -> to];
(*generate the text labels *)
text = Map[Text[#[[1]], #[[2]], {-1, 0}] &, Thread[{funNames, pos}]];
Plot the final result (added a little of padding to plot range so that
the labels added are seen completely)
Plot[funs, {x, from, to},
PlotRangePadding -> {1, 1},
PlotStyle -> {Red, Green, Blue},
PlotRange -> All,
Epilog -> text
]
update (1)
Sam asked below for an simpler way. I am not sure now. But one way to make it easier to use this method, is to make a function and then simply call this function once to generate the Text labels. You can put this function where you put all your other functions you use all the time, and just call it.
Here is something: First write the function
(*version 1.1*)
myLegend[funs_List, (*list of functions to plot*)
x_, (*the independent variable*)
from_?(NumericQ[#] && Im[#] == 0 &),(*the x-axis starting plot range*)
to_?(NumericQ[#] && Im[#] == 0 &) (*the x-axis ending plot range*)
] := Module[{funNames, pos, text, labelOffset = -1.3},
(*make label names*)
funNames = Style[#, 12] & /# funs;
(*generated the coordinates at the end of the plot lines*)
pos = Map[{to, #} &, funs /. x -> to];
(*generate the Text calls*)
text = Map[Text[#[[1]], #[[2]], {labelOffset, 0}] &,
Thread[{funNames, pos}]]
];
And now just call the above any time you want to plot with labels. It will be just 1-2 extra lines of code. like this:
Clear[x]
from = -5; to = 2;
funs = {Exp[x], 2^x, 3^x};
Plot[funs, {x, from, to}, PlotRangePadding -> {1, 1},
PlotStyle -> {Red, Green, Blue}, PlotRange -> All,
Epilog -> myLegend[funs, x, from, to]]
Here are few examples:
You can modify it as you want.
Alternative way with Tooltip displaying labels while the mouse pointer is at the function graphs :
Plot[Tooltip#{Exp[x], 2^x, 3^x}, {x, -5, 2}, AspectRatio -> Automatic,
PlotStyle -> {Red, Green, Blue}]
One way is to use PlotLegends
(I do not like it too much, but it is an easy way to do what you want)
<< PlotLegends`
Clear[x];
funs = {Exp[x], 2^x, 3^x};
legends = Map[Text#Style[#, "TR", 12] &, funs];
Plot[Evaluate#funs, {x, -5, 2}, AspectRatio -> Automatic,
PlotStyle -> {Red, Green, Blue}, PlotLegend -> legends]
see help to customize the legend more. The above uses defaults.
http://reference.wolfram.com/mathematica/PlotLegends/tutorial/PlotLegends.html

How to decrease file size of exported plots while keeping labels sharp

When exporting rather complicated plots (especially ListDensityPlot) as a PDF or EPS (for publication, for example), the resulting file size can be quite large. For example:
data = Flatten[Table[{f0, f, Exp[-(f - f0)^2/25^2]}, {f0, 500, 700, 5}, {f, 300,
900}], 1];
plot=ListDensityPlot[data,PlotRange->{Automatic,Automatic,{0,1}},InterpolationOrder->0]
This example data set is on the order of the size I typically work with. When I export using Export["C:\\test.pdf", plot], it generates a PDF file 23.9MB in size. If I instead try Export["C:\\test1.pdf", Rasterize[plot]] it is far smaller, but the integrity and rescalability of the image naturally suffers.
This is complicated further if my actual figure is a combined plot, such as (Edit: f goes to 900)
plot2 = Show[plot, Plot[x, {x, 500, 900}, PlotStyle -> Thick]]
(or with some usage of Epilog) where I'd love to have the background ListDensityPlot be rasterized, but keep the other markup and plots in ``vector'' form. Or at the very least, the frame labels be non-rasterized.
Is there any way to do this?
Or, to accomplish the same goal via some other clever method?
Update
I've checked out the related question, but that's gotta be way more complicated than it needs to be (essentially exporting then importing). I've been able to utilize some of the tricks in that question to extract the plot separately from the axes:
axes = Graphics[{}, Options[plot2]]
plots = Graphics[plot2[[1]]]
But, the plots term loses the AspectRatio and PlotRange, etc. plots can be hit with a Rasterize, but it needs dimensional fixing.
And then, how to combine them together?
This is exactly the kind of problem for which I wrote the function linked here:
http://pages.uoregon.edu/noeckel/computernotes/Mathematica/listContourDensityPlot.html
It's based on the same idea as in Heike's answer -- I just added some more features so that you can safely change the aspect ratio, opacity, and combine with other plots. See my comment in Heike's answer.
To try it with your data, do something like this:
plot = Show[
listContourDensityPlot[data,
PlotRange -> {Automatic, Automatic, {0, 1}},
InterpolationOrder -> 0, Contours -> None],
Graphics[Line[{{500, 500}, {700, 700}}]]]
There are a couple of similar functions linked from the parent page, too.
If you're dealing with 2D plots, you could combine a rasterized plot with vectorized axes by using Inset. For example
plot2 = ListDensityPlot[data,
PlotRange -> {Automatic, Automatic, {0, 1}},
InterpolationOrder -> 0, Axes -> False, Frame -> False,
PlotRangePadding -> 0];
plotRange = PlotRange /. AbsoluteOptions[plot2, PlotRange];
plot = Graphics[{
Inset[Image[plot2], plotRange[[All, 1]], {Left, Bottom}, Scaled[{.96, .96}]],
Line[{{500, 500}, {700, 700}}]},
Frame -> True, AspectRatio -> 1,
PlotRange -> plotRange, PlotRangePadding -> Scaled[.02]]
Export["test.pdf", plot]
produces a .pdf of about 400 KB. The frame, tick marks, and black line are still vectorized, so they stay sharp when zooming in:
If you are exporting as PDF, EPs or WMF, then the text should remain as vectors even if you have a rasterized component to the graphics.
I think the trick is to set the number of plot points to some low number in the ListDensityPlot command and then export as PDF as normal.
How about just plotting the function rather than making a list?
plot=DensityPlot[Exp[-(f - f0)^2/25^2], {f0, 500, 700}, {f, 300, 900},
Epilog -> {Thick, Line[{{500, 500}, {700, 700}}]}, PlotPoints -> 50]
Export["test.pdf", plot]
file size 1.1MB

How to add custom ColorFunction in FillingStyle with Opacity

I want to plot a series of lines with one half-space filled for each line. By setting opacity to something less than 1, I want to make the overlaps stand out. What I have looks something like this:
Plot[Table[x + a, {a, 0, 5}], {x, -1/2, 1/2},
RegionFunction -> Function[{x, y}, y < 5],
Filling -> 5, FillingStyle -> Directive[Opacity[0.25]]]
This is fine. Now I want to also shade the colors for each half space in a particular way. Instead of the flat shading for each at present, say I want to shade it by the y value. I.e., if the flat shade color is blue, the shade of blue is scaled by y (0 most intense or 5 most intense doesn't matter). So at the first overlap, it automatically becomes 2y, 3y when two half-spaces overlay.
How do I do this?
You could try ParametricPlot. For example
ParametricPlot[
Table[{s, i + s/2 + t}, {i, 0, 2}], {s, 0, 1}, {t, 0, 3},
Mesh -> False, PlotStyle -> Automatic,
ColorFunctionScaling -> False,
PlotRange -> {Automatic, {0, 3}},
ColorFunction -> Function[{x, y, s, t},
Directive[Opacity[0.2], ColorData["NeonColors"][y/3]]],
AspectRatio -> 1]
Result:

Getting coordinates of manually drawn points

I have a graph as a result of executing ListPlot[] function.
I can manually edit this graph by moving points to a different location
and also adding new points using the Drawing Tools.
How do I get the coordinates of new and changed points from the edited graphics?
I'm not sure if the following is anything like what you want,but nevertheless:
If I use ListPlot as follows:
lp1 = Labeled[
ListPlot[Diagonal#Table[{x, y}, {x, 0, 5}, {y, 5}],
PlotStyle -> {Directive[Red, PointSize[Large]]}], "lp1"];
By double clicking on one of the red points twice to get the selection to the level of the points, I can then move the individual points, e.g., to make the points lie on a curve (rather than a straight line). I now want to extract these points (and say use them in a new ListPlot) [see plots below]
If I click on the bracket of the plot graphic and use "Show Expression" (Command Shift E on a Mac), I can 'see' the coordinates of the modified points which may then be extracted. For example:
expr = Cell[
BoxData[GraphicsBox[{RGBColor[1, 0, 0], PointSize[Large],
PointBox[{{0., 1.}, {0.8254488458250212,
2.886651181634783}, {1.9301795383300084`,
3.925201233010209}, {3.046546974446661,
4.597525796319094}, {4., 5.}}]},
AspectRatio -> NCache[GoldenRatio^(-1), 0.6180339887498948],
Axes -> True, PlotRange -> Automatic,
PlotRangeClipping -> True]], "Input",
CellChangeTimes -> {{3.504427833788156*^9, 3.50442786823486*^9}}];
Modifying a very useful approach originally suggested by Yaroslav Bulatov, which may be found here
modpoints = Flatten[Cases[expr, PointBox[___], Infinity][[All, 1]], {{2, 1}}]
EDIT
As pointed out by belisarius, it is desirable to be able to extract 'manually' added points (which may be added to the generated plot using 'point' from the Drawing Tools palette). A better way of extracting (after 'Show Expression' ...) is probably the following:
modpoints = Cases[Cases[expr, PointBox[___],
Infinity], {_?NumericQ, _?NumericQ}, Infinity]
Of course, 'Show Expression' is not the only approach.
InputForm is another possibility. For example,
expr2 = InputForm[ListPlotGraphic]
modpoints = Cases[Cases[expr, Point[___],
Infinity], {_?NumericQ, _?NumericQ}, Infinity]
where "ListPlotGraphic" is the modified graphic (inserted by 'copy and paste'), will also work.
Example plots
Addendum
The above can be automated with a little notebook programming:
lp1 = Labeled[
ListPlot[Diagonal#Table[{x, y}, {x, 0, 5}, {y, 5}],
PlotStyle -> {Directive[Red, PointSize[Large]]}],
Button["Print points",
With[{nb = ButtonNotebook[]},
SelectionMove[nb, All, CellContents];
Print[Cases[NotebookRead[nb],
PointBox[{{_?NumericQ, _?NumericQ} ..}] |
PointBox[{_?NumericQ, _?NumericQ}], Infinity]]]]]
Running the above, moving the last two original (red) points and adding a couple of extra points in blue with the drawing tools then pressing the button yields
You can see that there is a single PointBox for the original data and a new PointBox for each of the added points. Of course, by modifying the above code, you can do more than simply print out the raw point coordinates.
This approach makes every data point a locator that can be moved. New locators can be added and old ones deleted as appropriate. The best fit and variance are updated after every change.
Here's some data of some exponential growth with some errors and a data point missing
data = Delete[Table[{t, (1 + RandomReal[{-.2, .2}])Exp[t]}, {t, 0, 2, .2}], 6];
A little formatting command:
nForm = NumberForm[#, {2, 2}, NumberPadding -> {"", "0"}] &;
Finally, here's the code to make the manipulable graphics. New locators/data points are added using Alt-Click (or Ctrl-Alt-Click on linux). If you click on the list of points on the left, then a new window is opened containing the points in input form.
Manipulate[
LocatorPane[Dynamic[pts, {None, Temporary, Automatic}],
nlm = Block[{a,b,t}, NonlinearModelFit[Sort[pts], a Exp[t] + b, {a, b}, t]];
Show[Plot[{Exp[t], nlm[t]}, {t, 0, 2},
PlotStyle -> {{Thick, LightGray}, Dotted}, PlotRangePadding -> Scaled[0.1]],
ListPlot[data, PlotStyle -> Blue], AxesLabel -> Block[{t,f}, {t, f[t]}]],
LocatorAutoCreate -> True, Appearance -> Style["\[CircleDot]", Red]],
{nlm, None}, {{pts, data}, None},
Dynamic[Pane[EventHandler[
nForm#Grid[Prepend[pts, {"x", "y"}], Dividers -> {False, 2 -> True}],
{"MouseClicked" :> (CreateDocument[{ExpressionCell[nlm["Data"], "Output"]},
WindowTitle -> "Data"])}], ImageSize -> {100, 250},
ImageSizeAction -> "Scrollable", Scrollbars -> {False, True}]],
Pane[Dynamic[nForm#Row#{nlm,Row[{"\tvariance = ",nlm["EstimatedVariance"]}]}]],
ControlPlacement -> {Left, Left, Left, Top}]
In the above I've used the locators to correct a couple of outliers and restored the missing data point.
The easy option is to use the "Get Coordinates" menu option. If you right click on the graphic, in the pop-up menu you'll see "Get Coordinates" which allows you to mouse-over a point and see that point's coordinates. Of course this isn't going to be accurate... but the way you're editing the graphic isn't very accurate either.
You could use the InputForm (or FullForm) function, but I am not sure how well this works...
In[1]:= a = ListPlot[{{1, 0}, {0, 1}, {1, 1}}];
a // InputForm
Out[2]//InputForm=
Graphics[{{{}, {Hue[0.67, 0.6, 0.6], Point[{{1., 0.}, {0., 1.}, {1., 1.}}]},
{}}}, {AspectRatio -> GoldenRatio^(-1), Axes -> True, AxesOrigin -> {0, 0},
PlotRange -> {{0., 1.}, {0., 1.}}, PlotRangeClipping -> True,
PlotRangePadding -> {Scaled[0.02], Scaled[0.02]}}]
You'll notice that there's a Point expression in there.
The third option would be to use Locator in some way I guess.

Plotting horizontal and vertical lines in Mathematica

In Mathematica, how do you plot a horizontal line at a given number? How do you plot a vertical line at a given number?
If you're actually using Plot (or ListPlot, et c.), the easiest solution is to use the GridLines option, which lets you specify the x- and y-values where you want the lines drawn. For instance:
Plot[Sin[x], {x, 0, 2 \[Pi]},
GridLines -> {{0, \[Pi]/2, \[Pi], 3 \[Pi]/2, 2 \[Pi]},
{-1, -Sqrt[3]/2, -1/2, 0, 1/2, Sqrt[3]/2, 1}}]
EDIT to add:
Of course, this solution works if you just want to draw a line at a single, given number. For instance, if you want to reproduce the second example from dreeve's answer:
Plot[Sin[x], {x, 0, 2 Pi},
GridLines -> {{4}, {}}]
For the case of horizontal lines when using Plot the easiest trick is to just include additional constant functions:
Plot[{Sin[x], .75}, {x, 0, 2Pi}]
For vertical lines, there's the Epilog option for Plot and ListPlot:
Plot[Sin[x], {x, 0, 2Pi}, Epilog->Line[{{4,-100}, {4,100}}]]
But probably the best is the GridLines option given in Pillsy's answer.
One approach would be to add Line graphic primitives to your graphics:
p1 = Plot[Sin[x], {x, -2*Pi,2*Pi}];
l1 = Graphics#Line[{{-2Pi,.75},{2Pi,.75}}]; (* horizontal line at y==.75 *)
Show[p1,l1]
Another approach would be to fiddle around with GridLines.
Use the Gridlines command like so:
Plot[
1/(15*E^((x - 100)^2/450)*Sqrt[2*Pi]),
{x, 55, 145},
GridLines -> {{85, 115}, {}}
]
TRANSLATION
In the code above I plot a normal curve:
1/(15*E^((x - 100)^2/450)*Sqrt[2*Pi])
Then tell the plot what part of the x-axis I want it to display:
{x, 55, 145}
Then I add the vertical gridlines where I want them at 85 and 115.
GridLines -> {{85, 115}, {}}
Note you need to provide the blank {} where Gridlines would expect the horizontal grid lines locations.
An alternative is to think of the vertical line as a straight line of infinite slope. So for a vertical line at located at x=2*pi, we can do something like this:
Plot[{Sin[x], 10^10 (x - 2 \[Pi])}, {x, 0, 10}, PlotRange -> {-1, 1}]
click to see the image
Note that the term 10^10 mimics an infinite slope. If you do not use the option PlotRange -> {-1, 1}, the "dominant" function is the straight line so the Sin[x] function do effectively appears as an horizontal line.

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