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rr-s4grimport

Get xy path coordinates of letters in a word

I wish to use gganimate and tweener to morph some letters into other letters. Thus, I need a dataframe of x, y coordinates for each letter in a word as input to ggplot.

I'm not really sure how to do this, but my thinking is that library(grImport) may help.

I created a Postscript file of the word "hello" by printing and then saving the output to Postscript. It's here.

This code reads hello.ps

library(grImport)

PostScriptTrace("figures/hello.ps", "hello.xml")
hello <- readPicture("hello.xml")
grid.picture(hello)

hello is an S4 class object.

Am I correct in thinking that the structure of hello holds x,y coordinates for each letter of the the word "hello"?

If so, how do I extract those coordinates?

Solution

  • For the record the solution is:

    # Extract x, y coordinates of path from S4 object of class Picture
# letters[i], i is the index into the word, "hello".

x <- hello@paths$text@letters[2]$path@x 
y <- hello@paths$text@letters[2]$path@y