Edit Automatic PlotRange

Question

if I have a plot let us say

Plot[x^2 - 5 x - 10, {x, 0, 8}]

I want o check if there is a way to know the automatic plot range and to add or subtract from that range as I need.

I will assume something fictitious like this:

Plot[x^2 - 5 x - 10, {x, 0, 8}, PlotRange -> (Automatic + {0, 10})]

is there a way to do something like this?

Are you asking about y axis? Plot[x^2 - 5 x - 10, {x, 0, 8}, PlotRangePadding -> {Automatic, {Automatic, 8}}] ? — Kuba, May 25 '14 at 15:20
@Kuba yes I am asking about y axis. thanks for the answer. can that be applied for both sides of y axis (+y and -y)? — Basheer Algohi, May 25 '14 at 15:37
@Algohi It's unclear what it is about. PlotRange padding will not create parts of plot that are not already there. Take as example Tan[x]. About x axis, isn't it the second argument of Plot? — Kuba, May 25 '14 at 16:08
pretty sure in general you need to generate the plot use AbsoluteOptions[] or some such to get the range then re-plot. — george2079, May 25 '14 at 17:32
@kuba PlotRangePadding is what I was looking for. It appears I can control both sides of each axes. What is was looking for is something like this : Plot[{10, x^2 - 5 x - 10, -16.5}, {x, 0, 8}, PlotRangePadding -> {{5, 4}, {10, 20}}] — Basheer Algohi, May 26 '14 at 01:35
@george2079 AbsoluteOptions[] is new to me taht I can get the values of some options. thanks — Basheer Algohi, May 26 '14 at 01:36

score 5 · Answer 1 · answered May 27 '14 at 15:38

just for completeness here is the issue with padding, if automatic ranging clipped the function, PlotRangePadding does not recover the clipped portion:

 Plot[ 1/x , {x, -1, 1},
     PlotRangePadding -> {Automatic, {10, 10}}]

enter image description here

Fix by generating the plot first to get the auto generated range then again with manual padding:

 Plot[1/x, {x, -1, 1}, 
     PlotRange -> ({#[[1]], #[[2]] + {-10, 10}} &@
      (PlotRange /.  AbsoluteOptions[Plot[ 1/x , {x, -1, 1}]]))]

enter image description here

you are right about this. I will consider this way also. great thanks. — Basheer Algohi, May 27 '14 at 17:10

score 3 · Accepted Answer · answered May 26 '14 at 07:25

3

OP confirmed that PlotRangePadding is what solves the problem.

Plot[x^2 - 5 x - 10, {x, 0, 8},   PlotRangePadding -> {Automatic, {Automatic, 8}}]

answered May 26 '14 at 07:25

Kuba

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Edit Automatic PlotRange

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