R: Describe a Set of Typeset Glyphs

glyphInfo {grDevices}

R Documentation

Describe a Set of Typeset Glyphs

Description

Create an object that contains information about typeset glyphs. This includes glyph identifiers, glyph locations, font, colour and rotation information, and metric information.

Usage

glyphInfo(id, x, y, font, size, fontList, 
          width, height, hAnchor, vAnchor,
          col=NA, rot=0)

glyphFont(file, index, family, weight, style, PSname=NA)
glyphFontList(...)
glyphAnchor(value, label)
glyphWidth(w, label="width", left="left")
glyphHeight(h, label="height", bottom="bottom")
glyphWidthLeft(w, label)
glyphHeightBottom(h, label)
glyphJust(just, ...)
## S3 method for class 'GlyphJust'
glyphJust(just, ...)
## S3 method for class 'character'
glyphJust(just, ...)
## S3 method for class 'numeric'
glyphJust(just, which=NULL, ...)

Arguments

`id`	Numeric vector of glyph identifiers (index of glyph within font file).
`x`, `y`	Numeric locations of glyphs in (big) points (1/72 inches).
`font`	Integer index into `fontList`.
`size`	Numeric size of glyphs (in points).
`fontList`	List of glyph fonts, as generated by `glyphFont()`.
`width`	Overall width of glyphs. Can be a single numeric value, but can also be the result from a call to `glyphWidth()`.
`height`	Overall height of glyphs. Can be a single numeric value, but can also be the result from a call to `glyphHeight()`.
`hAnchor`	Horizontal anchors for justifying glyphs relative to the (`x`, `y`) location. Can be a single numeric value (against which to `"left"` justify), but can also be result from a call to `glyphAnchor()`.
`vAnchor`	Vertical anchors for justifying glyphs relative to the (`x`, `y`) location. Can be a single numeric value (against which to `"bottom"` justify), but can also be result from a call to `glyphAnchor()`.
`col`	An R colour value for each glyph. Can be `NA`.
`rot`	The angle to rotate each glyph.
`file`	Character path to font file.
`index`	Numeric index of font within font file.
`family`	Character name of font family.
`weight`	Numeric weight of glyphs (400 is normal, 700 is bold).
`style`	Character style of glyphs (`"normal"`, `"italic"`, or `"oblique"`).
`PSname`	The PostScript name for each font. Can be `NA`.
`value`, `w`, `h`	A numeric value.
`label`, `left`, `bottom`	A character value.
`just`	A justification value. Either a character value like `"left"` or a numeric value like `0`.
`which`	When `x` is numeric, a character value identifying which width metric the numeric value is relative to.
`...`	Further arguments passed to other methods.

Details

Multiple anchors can be specified so as to allow different character-based justifications of the glyphs relative to the (x, y) location. Horizontal anchors with labels "left", "centre", and "right" are required. It is possible to specify a single numeric hAnchor, which is treated as the "left" anchor, or a single anchor with label "left", in which case the other required anchors will be calculated based on the required width of the glyphs (see below). Vertical anchors with labels "bottom", "centre", and "top" are required. It is possible to specify a single numeric vAnchor, which is treated as the "bottom" anchor, or a single anchor with label "bottom", in which case the other required anchors will be calculated based on the required height of the glyphs (see below). An example of a non-required anchor is a vertical anchor with the label "baseline" so that the glyphs can be placed with their baseline at the y location.

Multiple widths and heights can be specified so as to allow different numeric-based justifications of the glyphs relative to the (x, y) location, e.g., 0 for left-justification and 1 for right-justification, but with any value in between or even outside those limits also possible. A width with label "width", relative to the "left" horizontal anchor, is required, but if a single numeric value is given, that is assumed to be the required width. A height with label "height", relative to the "bottom" vertical anchor is required, but if a single numeric value is given, that is assumed to be the required height. An example of a non-required width is a "tight" width that is relative to a "left-bearing" horizontal anchor, so that the glyphs can be justified relative to a bounding box around the glyph ink, rather than a bounding box that includes left and right bearings.

glyphWidthLeft() and glyphWidthHeight() provide an API for code that needs to access the relevant anchors for width and height metrics.

Value

The result from glyphInfo() is an "RGlyphInfo" object, essentially a data frame with each row containing id, location, font, colour and rotation for a glyph. The metric information (widths and anchors) are stored as attributes of the data frame.

glyphAnchor(), glyphWidth(), and glyphHeight() return values that can be used to specify width, height, hAnchor, and vAnchor values to glyphInfo().

Warning

Any glyph with NA in any of id, x, y, size or rot is silently dropped.

[Package grDevices version 4.5.0 Index]