calcStringMetric

0th

Percentile

Calculate Metric Information for Text

This function returns the ascent, descent, and width metric information for a character or expression vector.

Keywords
dplot
Usage
calcStringMetric(text)
Arguments
text

A character or expression vector.

Value

A list with three numeric components named ascent, descent, and width. All values are in inches.

WARNING

The metric information from this function is based on the font settings that are in effect when this function is called. It will not necessarily correspond to the metric information of any text that is drawn on the page.

See Also

stringAscent, stringDescent, grobAscent, and grobDescent.

Aliases
  • calcStringMetric
Examples
library(grid) grid.newpage() grid.segments(.01, .5, .99, .5, gp=gpar(col="grey")) metrics <- calcStringMetric(letters) grid.rect(x=1:26/27, width=unit(metrics$width, "inches"), height=unit(metrics$ascent, "inches"), just="bottom", gp=gpar(col="red")) grid.rect(x=1:26/27, width=unit(metrics$width, "inches"), height=unit(metrics$descent, "inches"), just="top", gp=gpar(col="red")) grid.text(letters, x=1:26/27, just="bottom") test <- function(x) { grid.text(x, just="bottom") metric <- calcStringMetric(x) if (is.character(x)) { grid.rect(width=unit(metric$width, "inches"), height=unit(metric$ascent, "inches"), just="bottom", gp=gpar(col=rgb(1,0,0,.5))) grid.rect(width=unit(metric$width, "inches"), height=unit(metric$descent, "inches"), just="top", gp=gpar(col=rgb(1,0,0,.5))) } else { grid.rect(width=unit(metric$width, "inches"), y=unit(.5, "npc") + unit(metric[2], "inches"), height=unit(metric$ascent, "inches"), just="bottom", gp=gpar(col=rgb(1,0,0,.5))) grid.rect(width=unit(metric$width, "inches"), height=unit(metric$descent, "inches"), just="bottom", gp=gpar(col=rgb(1,0,0,.5))) } } tests <- list("t", "test", "testy", "test\ntwo", expression(x), expression(y), expression(x + y), expression(a + b), expression(atop(x + y, 2))) grid.newpage() nrowcol <- n2mfrow(length(tests)) pushViewport(viewport(layout=grid.layout(nrowcol[1], nrowcol[2]), gp=gpar(cex=5, lwd=.5))) for (i in 1:length(tests)) { col <- (i - 1) %% nrowcol[2] + 1 row <- (i - 1) %/% nrowcol[2] + 1 pushViewport(viewport(layout.pos.row=row, layout.pos.col=col)) test(tests[[i]]) popViewport() }
Documentation reproduced from package grid, version 3.4.1, License: Part of R 3.4.1

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