How to left align text in annotate from ggplot2

问题:

My example is:

qplot(mtcars$mpg) + 
  annotate(geom = "text", x = 30, y = 3, label = "Some text\nSome more text")

How do I get the text here to be left aligned? So that the 'Some's line up with each other.

回答1:

hjust = 0 does what you want. hjust stands for horizontal justification, 0 will be left-justified, 0.5 will be centered, and 1 will be right-justified.

qplot(mtcars$mpg) +
    annotate(geom = "text", x = 30, y = 3,
             label = "Some text\nSome more text",
             hjust = 0)

See also vjust for vertical justification.

In ggplot2, these arguments are present any time text preferences are set. They work for annotate, geom_text, or in element_text when adjusting theme options.

If you look at ?geom_text, you can find text string options: "left", "middle", or "right", (for hjust), "top", "center", "bottom" for vjust, and for either "inward" and "outward" which will always adjust in toward or out away from the center.

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This behavior is similar in many base graphics functions, such as the adj argument for par, used by text(), mtext(), and title(), which can be vector of length 2 for the horizontal and vertical justificatons. Also the hadj and padj arguments to axis() for justifications horizontal to and perpendicular to the axis.