dynTextGrob: Create Text with Changing Size
In sisal: Sequential Input Selection Algorithm

Description Usage Arguments Details Value Author(s) See Also Examples

This function creates a text object. When drawn, its size changes automatically according to the space available.

dynTextGrob(label, x = 0.5, y = 0.5, width = 1, height = 1,
            default.units = "npc", just = c(0.5, 0.5),
            hjust = NULL, vjust = NULL, rot = 0, rotJust = TRUE,
            rotHjust = NULL, rotVjust = NULL, resize = TRUE,
            sizingWidth = NULL, sizingHeight = NULL,
            adjustJust = TRUE, takeMeasurements = FALSE,
            name = NULL, gp = gpar(), vp = NULL)

`label`	a `character` or `expression` vector, or a `list` containing both character strings and mathematical expressions. These are the text items to be drawn.
`x`	a `numeric` vector or `unit` of x locations for the labels.
`y`	a `numeric` vector or `unit` of y locations for the labels.
`width`	the space available for the labels in the width direction of the viewport. Used for computing the fontsize.
`height`	the space available for the labels in the height direction of the viewport. Used for computing the fontsize.
`default.units`	default unit to use when dimensions or locations are unitless numbers. See `unit`.
`just`	a `numeric` or `character` vector with one or two elements for setting the same justification for all labels. See `textGrob`.
`hjust`	a `numeric` vector for setting horizontal justification of individual labels. If given, overrides `just`.
`vjust`	a `numeric` vector for setting vertical justification of individual labels. If given, overrides `just`.
`rot`	a `numeric` vector for setting the rotation angle of individual labels in degrees.
`rotJust`	a `logical` vector which affects the justification of individual labels. If an element is `FALSE`, the corresponding label is first justified according to `hjust` (reading direction) and `vjust` (the perpendicular direction), then rotated. This is the way a `textGrob` works. If an element is `TRUE`, the concept is: align the label with the other labels according to `rotHjust` (reading direction) and `rotVjust` (the perpendicular direction), then rotate, and finally justify in the width and height directions of the viewport with `hjust` and `vjust`, respectively.
`rotHjust`	a `numeric` vector or `NULL`. When the corresponding element of `rotJust` is `TRUE`, `rotHjust` sets the justification of a label in the reading direction. If `NULL` or an `NA` element is encountered, an automatic value will be computed based on rotation angle (`rot`) and justification along the viewport axes (`just`, `hjust` and `vjust`).
`rotVjust`	a `numeric` vector or `NULL`. Set the justification of labels perpendicular to the reading direction when `rotJust` is `TRUE`. See `rotHjust`.
`resize`	a `logical` flag. If `TRUE` (the default), the fontsize of the labels will be adjusted according to the space available. If `FALSE`, the size will remain constant, even if the graphical object is drawn in a viewport with a different setting for the `"cex"` graphical parameter.
`sizingWidth`	If `resize` is `TRUE`, a `numeric` value given here sets the width of the grob used when calculating fontsize at drawing time. If `NULL` (the default), the size is computed from the actual dimensions of the labels.
`sizingHeight`	See `sizingWidth`, only height instead of width.
`adjustJust`	A `logical` flag. If `TRUE` (the default), adjustments are made to the justification of the labels instead of passing the justification settings straight to the underlying `textGrob`(s). The justification of labels given in `expression` form will be unified with the justification of `character` labels, meaning that a setting of `vjust = 0` will align the baselines of the labels and `vjust = 1` will align the labels at lineheight, or at a multiple of lineheight in case of multiline `character` labels. The labels will also be shifted so that there is room for descenders.
`takeMeasurements`	A `logical` flag. If `TRUE`, only measurements of labels will be returned instead of a graphical object. An example of where this might be useful is when several labels should have the same fontsize but different graphical parameters such as color, or when the labels should be drawn in different viewports. See the source of `sisalTable`, particularly `makeContent.sisalTable`, for an example. If `FALSE` (the default) a graphical object will be returned.
`name`	a `character` string identifier for the graphical object returned by the function. If `NULL` (the default), a name will be assigned automatically.
`gp`	graphical parameters. See `gpar`.
`vp`	a `"viewport"` object, the name of a viewport object, a `vpPath` object pointing to a viewport or `NULL` (the default). If not `NULL`, this graphical object will be drawn in the given viewport. The name or the path must point to a descendant of the viewport that is current at drawing time. See `current.vpPath`, `current.vpTree`, `downViewport` and `grid.draw`.

The number of labels created is the maximum of the lengths of x and y. Variables are recycled to that length if necessary.

All labels of one "dynText" grob have the same fontsize.

If takeMeasurements is FALSE (the default), returns a grob of class "dynText". It can be drawn with grid.draw.

If takeMeasurements is TRUE, returns a list containing measurements of the labels.

Mikko Korpela

See function textGrob in package grid.

library(grid)
grid.newpage()
grid.draw(dynTextGrob("Hello", vjust = 0, y = 0))
grid.draw(dynTextGrob(list(expression(y==x^2),
                           "Hello,\ntry resizing me!"),
                      x = rep(1, 2), y = 1, rot = -45,
                      hjust = 1, vjust = 1,
                      rotHjust = c(0, 1), rotVjust = 1))