[R] depth of labels of axis
jszhao at yeah.net
Sat Sep 6 01:04:41 CEST 2014
On 2014/9/4 12:24, David Winsemius wrote:
> On Sep 3, 2014, at 10:05 PM, Jinsong Zhao wrote:
>> On 2014/9/3 21:33, Jinsong Zhao wrote:
>>> On 2014/9/2 11:50, David L Carlson wrote:
>>>> The bottom of the expression is set by the lowest character (which can
>>>> even change for subscripted letters with descenders. The solution is
>>>> to get axis() to align the tops of the axis labels and move the line
>>>> up to reduce the space, e.g.
>>>> plot(1:5, xaxt = "n")
>>>> axis(1, at = 1:5, labels = c(expression(E[g]), "E", expression(E[j]),
>>>> "E", expression(E[t])), padj=1, mgp=c(3, .1, 0))
>>>> # Check alignment
>>>> abline(h=.7, xpd=TRUE, lty=3)
>>> yes. In this situation, padj = 1 is the fast solution. However, If there
>>> are also superscript, then it's hard to alignment all the labels.
>>> If R provide a mechanism that aligns the label in axis() or text() with
>>> the baseline of the character without the super- and/or sub-script, that
>>> will be terrific.
>> it seems that the above wish is on the Graphics TODO lists:
>> Allow text adjustment for mathematical annotations which is relative to a text baseline (in addition to the current situation where adjustment is relative to the bounding box).
> In many case adding a phantom argument will correct aliognment problems:
> plot(1:5, xaxt = "n")
> axis(1, at = 1:5, labels = c(expression(E[g]), E~phantom(E[g]), expression(E[j]),
> E~phantom(E[g]), expression(E[t])))
> abline(h=.7, xpd=TRUE, lty=3)
> Notice that c(expression(.), ...) will coerce all items separated by commas to expressions, sot you cna just put in "native" expression that are not surrounded by the `expression`-function
> c(expression(E[g]), E~phantom(E[g]), expression(E[j]) ) #returns
> # expression(E[g], E ~ phantom(E[g]), E[j])
> The tilde is actually a function that converts parse-able strings into R language objects:
> c(expression(E[g]), E~phantom(E[g]), ~E[j])
I never knew the trick of c(expression(.), ...). It simplifies my code a
Thanks a lot.
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