texts: add text
In rgl: 3D Visualization Using OpenGL

Description Usage Arguments Details Value Fonts See Also Examples

Adds text to the scene. The text is positioned in 3D space. Text is always oriented towards the camera.

rgl.texts(x, y = NULL, z = NULL, text, 
            adj = 0.5, pos = NULL, offset = 0.5, 
            family = par3d("family"), font = par3d("font"), 
            cex = par3d("cex"), useFreeType = par3d("useFreeType"), ...)
text3d(x, y = NULL, z = NULL, texts, adj = 0.5, pos = NULL, offset = 0.5,
       usePlotmath = is.language(texts), ...) 
texts3d(x, y = NULL, z = NULL, texts, adj = 0.5, pos = NULL, offset = 0.5,
       usePlotmath = is.language(texts), ...) 
rglFonts(...)

`x, y, z`	point coordinates. Any reasonable way of defining the coordinates is acceptable. See the function `xyz.coords` for details.
`text`	text character vector to draw
`texts`	text character vector to draw
`adj`	one value specifying the horizontal adjustment, or two, specifying horizontal and vertical adjustment respectively.

`pos`	a position specifier for the text. If specified, this overrides any `adj` value given. Values of 1, 2, 3 and 4, respectively indicate positions below, to the left of, above and to the right of the specified coordinates.
`offset`	when `pos` is specified, this value gives the offset of the label from the specified coordinate in fractions of a character width.
`family`	A device-independent font family name, or ""
`font`	A numeric font number from 1 to 5
`cex`	A numeric character expansion value
`useFreeType`	logical. Should FreeType be used to draw text? (See details below.)
`usePlotmath`	logical. Should `plotmath3d` be used for the text?
`...`	In `rgl.texts`, material properties; see `rgl.material` for details. In `rglFonts`, device dependent font definitions for use with FreeType. In the other functions, additional parameters to pass to `rgl.texts`.

The adj parameter determines the position of the text relative to the specified coordinate. Use adj = c(0, 0) to place the left bottom corner at (x, y, z), adj = c(0.5, 0.5) to center the text there, and adj = c(1, 1) to put the right top corner there. The optional second coordinate for vertical adjustment defaults to 0.5. Placement is done using the "advance" of the string and the "ascent" of the font relative to the baseline, when these metrics are known.

text3d and texts3d draw text using the r3d conventions. These are synonyms; the former is singular to be consistent with the classic 2-D graphics functions, and the latter is plural to be consistent with all the other graphics primitives. Take your choice!

If any coordinate or text is NA, that text is not plotted.

If usePlotmath is TRUE, the work will be done by the plotmath3d function instead of rgl.texts. This is the default if the texts parameter is “language”, e.g. the result of a call to expression or quote.

The text drawing functions return the object ID of the text object (or sprites, in case of usePlotmath = TRUE) invisibly.

rglFonts returns the current set of font definitions.

Fonts are specified using the family, font, cex, and useFreeType arguments. Defaults for the currently active device may be set using par3d, or for future devices using r3dDefaults.

The family specification is the same as for standard graphics, i.e. families
c("serif", "sans", "mono", "symbol")
are normally available, but users may add additional families. font numbers are restricted to the range 1 to 4 for standard, bold, italic and bold italic respectively; with font 5 recoded as family "symbol" font 1.

Using an unrecognized value for "family" will result in the system standard font as used in rgl up to version 0.76. That font is not resizable and font values are ignored.

If useFreeType is TRUE, then rgl will use the FreeType anti-aliased fonts for drawing. This is generally desirable, and it is the default if rgl was built to support FreeType.

FreeType fonts are specified using the rglFonts function. This function takes a vector of four filenames of TrueType font files which will be used for the four styles regular, bold, italic and bold italic. The vector is passed with a name to be used as the family name, e.g. rglFonts(sans = c("/path/to/FreeSans.ttf", ...)). In order to limit the file size, rgl ships with just 3 font files, for regular versions of the serif, sans and mono families. Additional free font files are available from the Amaya project at https://dev.w3.org/cvsweb/Amaya/fonts/. See the example below for how to specify a full set of fonts.

Full pathnames should normally be used to specify font files. If relative paths are used, they are interpreted differently by platform. Currently Windows fonts are looked for in the Windows fonts folder, while other platforms use the current working directory.

If FreeType fonts are not used, then bitmapped fonts will be used instead. On Windows these will be based on the fonts specified using the windowsFonts function, and are resizable. Other platforms will use the default bitmapped font which is not resizable.

Bitmapped fonts have a limited number of characters supported; if any unsupported characters are used, an error will be thrown.

r3d, plotmath3d

open3d()
famnum <- rep(1:4, 8)
family <- c("serif", "sans", "mono", "symbol")[famnum]
font <- rep(rep(1:4, each = 4), 2)
cex <- rep(1:2, each = 16)
text3d(font, cex, famnum, text = paste(family, font), adj = 0.5, 
       color = "blue", family = family, font = font, cex = cex)
## Not run: 
# These FreeType fonts are available from the Amaya project, and are not shipped
# with rgl.  You would normally install them to the rgl/fonts directory
# and use fully qualified pathnames, e.g. 
# system.file("fonts/FreeSerif.ttf", package = "rgl")

rglFonts(serif = c("FreeSerif.ttf", "FreeSerifBold.ttf", "FreeSerifItalic.ttf",
                 "FreeSerifBoldItalic.ttf"),
         sans  = c("FreeSans.ttf", "FreeSansBold.ttf", "FreeSansOblique.ttf",
                 "FreeSansBoldOblique.ttf"),
         mono  = c("FreeMono.ttf", "FreeMonoBold.ttf", "FreeMonoOblique.ttf",
                 "FreeMonoBoldOblique.ttf"),
         symbol= c("ESSTIX10.TTF", "ESSTIX12.TTF", "ESSTIX9_.TTF", 
                 "ESSTIX11.TTF"))

## End(Not run)

Warning messages:
1: In rgl.init(initValue, onlyNULL) : RGL: unable to open X11 display
2: 'rgl.init' failed, running with 'rgl.useNULL = TRUE'. 
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