drawLabels: Draw text labels on a base R plot
In jmw86069/jamba: Jam Base Methods

drawLabels

R Documentation

Draw text labels on a base R plot

Description

Draw text labels on a base R plot

Usage

drawLabels(
  txt = NULL,
  newCoords = NULL,
  x = NULL,
  y = NULL,
  lx = NULL,
  ly = NULL,
  segmentLwd = 1,
  segmentCol = "#00000088",
  drawSegments = TRUE,
  boxBorderColor = "#000000AA",
  boxColor = "#FFEECC",
  boxLwd = 1,
  drawBox = TRUE,
  drawLabels = TRUE,
  font = 1,
  labelCex = 0.8,
  boxCexAdjust = 1.9,
  labelCol = alpha2col(alpha = 0.8, setTextContrastColor(boxColor)),
  doPlot = TRUE,
  xpd = NA,
  preset = "default",
  adjPreset = "default",
  preset_type = "plot",
  adjX = 0.5,
  adjY = 0.5,
  panelWidth = "default",
  trimReturns = TRUE,
  verbose = FALSE,
  ...
)

Arguments

`txt`	character vector of labels, length equal to `x` and `y`.
`newCoords`	optional `data.frame` typically as a result of a previous call to `drawLabels()`. In general, it should contain colnames equivalent to the function parameters of `drawLabels()`.
`x`, `y`	vector of x- and y- coordinates.
`lx`, `ly`	optional vector of segment endpoint coordinates, used to draw a line from x,y coordinates to the segment lx,ly coordinate.
`segmentLwd`, `segmentCol`	vector of segment line widths, and colors, respectively. Each vector will be recycled to `length(txt)` as needed.
`drawSegments`	logical whether to draw segments, where applicable.
`boxBorderColor`	vector of colors used for the box border around each label.
`boxColor`	vector of colors used for the box background behind each label.
`boxLwd`	vector of box line widths, sent to `graphics::rect()`, this vector will be recycled to `length(txt)`.
`drawBox`	logical whether to draw boxes behind each text label.
`drawLabels`	logical whether to draw each text label.
`font`	vector of font values as described in `graphics::par()`, where 1=normal, 2=bold, 3=italics, 4=bold-italics.
`labelCex`	vector of cex values used for text labels. This vector will be recycled to `length(txt)` as needed.
`boxCexAdjust`	numeric vector length=2, used to expand the x-width and y-height of the box around around text labels.
`labelCol`	vector of label colors, by default it calls `jamba::setTextContrastColor()` to generate a color to contrast the background box color.
`doPlot`	logical whether to perform any plot operations. Set `FALSE` to calculate coordinates and return a `data.frame` of label coordinates, which can then be manipulated before calling `drawLabels()` again.
`xpd`	value compatible with `par("xpd")`, where NA allows labels anywhere in the device region, TRUE retricts labels within the figure region, and FALSE restricts labels within the plot region.
`preset`	vector of text values used to position text labels relative to the x,y coordinate, where "topleft" will position the label so the entire label box is top-left of the point, therefore the point will be at the bottom-right corner of the label box. When `preset` is anything by `"none"` the `adjX` and `adjY` values are ignored.
`adjX`, `adjY`	the text adjustment of labels relative to the x,y coordinate. The values are recycled to `length(txt)`.
`panelWidth`	`character` string or vector, recycled to the number of labels to be displayed. The argument indicates whether to size each label box relative to the plot panel width, intended when the label `preset` and `adjPreset` are set for the label to be inside the plot panel, e.g. `⁠preset="top", adjPreset="top"⁠`, or `⁠preset="topleft", adjPreset="topright"⁠`. Either both are centered, or one is "right" and the other is "left". In these cases, the label box is expanded to the full plot panel width, thus filling the full visible x-axis range for the plot panel. Allowed values for `panelWidth`: `"default"` size label boxes by text dimensions `"force"` size label to full plot panel width `"minimum"` size label at least the plot panel width, or larger if necessary to fit the text label `"maximum"` size label to the text label width, but no larger than the plot panel width
`trimReturns`	logical whether to trim leading and trailing return (newline) characters from labels.
`verbose`	logical whether to print verbose output.
`...`	additional arguments are passed to `graphics::segments()` when segments are drawn, to `graphics::rect()` when label boxes are drawn, and to `graphics::text()` when text labels are drawn.

Details

This function takes a vector of coordinates and text labels, and draws the labels with colored rectangles around each label on the plot. Each label can have unique font, cex, and color, and are drawn using vectorized operations.

TODO: In future allow rotated text labels. Not that useful within a plot panel, but sometimes useful when draw outside a plot, for example axis labels.

Value

invisible data.frame containing label coordinates used to draw labels. This data.frame can be manipulated and provided as input to drawLabels() for subsequent customized label positioning.

Examples

nullPlot(plotAreaTitle="");
dl_topleft <- drawLabels(x=par("usr")[1],
   y=par("usr")[4],
   txt="Top-left\nof plot",
   preset="topleft",
   boxColor="blue4");

drawLabels(x=par("usr")[2],
   y=par("usr")[3],
   txt="Bottom-right\nof plot",
   preset="bottomright",
   boxColor="green4");

drawLabels(x=mean(par("usr")[1:2]),
   y=mean(par("usr")[3:4]),
   txt="Center\nof plot",
   preset="center",
   boxColor="purple3");

points(x=c(par("usr")[1], par("usr")[2],
      mean(par("usr")[1:2])),
   y=c(par("usr")[4], par("usr")[3],
      mean(par("usr")[3:4])),
   pch=20,
   col="red",
   xpd=NA);

nullPlot(plotAreaTitle="");
title(main="place label across the full top plot panel", line=2.5)
dl_top <- drawLabels(
   txt=c("preset='topright', adjPreset='topright', \npanelWidth='force'",
      "preset='topright',\nadjPreset='bottomleft'",
      "preset='bottomleft', adjPreset='topright',\npanelWidth='force'"),
   preset=c("topright", "topright", "bottomleft"),
   adjPreset=c("topleft", "bottomleft", "topright"),
   panelWidth=c("force", "none", "force"),
   boxColor=c("red4",
      "blue4",
      "purple3"));
box(lwd=2);

opar <- par("mfrow"=c(1, 3), "xpd"=TRUE);
on.exit(par(opar));
isub <- c(force="Always full panel width",
   minimum="At least full panel width or larger",
   maximum="No larger than panel width");
for (i in c("force", "minimum", "maximum")) {
nullPlot(plotAreaTitle="", doMargins=FALSE);
title(main=paste0("panelWidth='", i, "'\n",
   isub[i]));
drawLabels(labelCex=1.2,
   txt=c("Super-wide title across the top\npanelWidth='force'",
   "bottom label"),
   preset=c("top", "bottom"),
   panelWidth=i,
   boxColor="red4")
}
par("mfrow"=c(1, 1));

jmw86069/jamba documentation built on March 26, 2024, 5:26 a.m.