Low-level functions for plotting text
This is a low-level function for plotting text. Users
should normally use the high-level function text3d instead.
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"), ...)
rglFonts(...)x, y, z |
point coordinates. Any reasonable way of defining the
coordinates is acceptable. See the function |
text |
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 |
offset |
when |
family |
A device-independent font family name, or "" |
font |
A numeric font number from 1 to 4 |
cex |
A numeric character expansion value |
useFreeType |
logical. Should FreeType be used to draw text? (See details below.) |
... |
In |
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.
rgl.texts returns 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. Font 5 is recoded as family "symbol"
font 1, but that is not supported unless specifically
installed, so should be avoided.
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 on non-Windows systems 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, the rgl package 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.
On Windows the system fonts are acceptable and are used
when useFreeType = FALSE (the current default in
r3dDefaults). Mappings to family names
are controlled by the grDevices::windowsFonts()
function.
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.
## 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)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.