cairo-scaled-font {RGtk2} | R Documentation

## cairo_scaled_font_t

### Description

Font face at particular size and options

### Methods and Functions

`cairoScaledFontCreate(font.face, font.matrix, ctm, option)`
`cairoScaledFontStatus(scaled.font)`
`cairoScaledFontExtents(scaled.font)`
`cairoScaledFontTextExtents(scaled.font, utf8)`
`cairoScaledFontGlyphExtents(scaled.font, glyphs, num.glyphs)`
`cairoScaledFontTextToGlyphs(scaled.font, x, y, utf8, utf8.len = -1)`
`cairoScaledFontGetFontFace(scaled.font)`
`cairoScaledFontGetFontOptions(scaled.font)`
`cairoScaledFontGetFontMatrix(scaled.font)`
`cairoScaledFontGetCtm(scaled.font)`
`cairoScaledFontGetScaleMatrix(scaled.font)`
`cairoScaledFontGetType(scaled.font)`
`cairoScaledFontSetUserData(scaled.font, key, user.data)`
`cairoScaledFontGetUserData(scaled.font, key)`
`cairoScaledFont(font.face, font.matrix, ctm, option)`

### Detailed Description

`CairoScaledFont` represents a realization of a font face at a particular size and transformation and a certain set of font options.

### Structures

`CairoScaledFont`

  A `CairoScaledFont` is a font scaled to a particular size and device resolution. A `CairoScaledFont` is most useful for low-level font usage where a library or application wants to cache a reference to a scaled font to speed up the computation of metrics.

  There are various types of scaled fonts, depending on the font backend they use. The type of a scaled font can be queried using `cairoScaledFontGetType`.

  Memory management of `CairoScaledFont` is done with `cairoScaledFontReference()` and `cairoScaledFontDestroy()`.

`CairoFontExtents`

  The `CairoFontExtents` structure stores metric information for a font. Values are given in the current user-space coordinate system.

  Because font metrics are in user-space coordinates, they are mostly, but not entirely, independent of the current transformation matrix. If you call `cairo_scale(cr, 2.0, 2.0)`, text will be drawn twice as big, but the reported text extents will not be doubled. They will change slightly due to hinting (so you can't assume that metrics are independent of the transformation matrix), but otherwise will remain unchanged. `CairoFontExtents` is a transparent-type.

  `ascent`

    [numeric] the distance that the font extends above the baseline. Note that this is not always exactly equal to the maximum of the extents of all the glyphs in the font, but rather is picked to express the font designer's intent as to how the font should align with elements above it.

  `descent`

    [numeric] the distance that the font extends below the baseline. This value is positive for typical fonts that include portions below the baseline. Note that this is not always exactly equal to the maximum of the extents of all the glyphs in the font, but rather is picked to express the font designer's intent as to how the the font should align with elements below it.

  `height`

    [numeric] the recommended vertical distance between baselines when setting consecutive lines of text with the font. This is greater than `ascent`+`descent` by a quantity known as the line spacing or external leading. When space is at a premium, most fonts can be set with only a distance of `ascent`+`descent` between lines.

  `maxXAdvance`

    [numeric] the maximum distance in the X direction that the the origin is advanced for any glyph in the font.

  `maxYAdvance`

    [numeric] the maximum distance in the Y direction that the the origin is advanced for any glyph in the font. this will be zero for normal fonts used for horizontal writing. (The scripts of East Asia are sometimes written vertically.)

`CairoTextExtents`

  The `CairoTextExtents` structure stores the extents of a single glyph or a string of glyphs in user-space coordinates. Because text extents are in user-space coordinates, they are mostly, but not entirely, independent of the current transformation matrix. If you call `cairo_scale(cr, 2.0, 2.0)`, text will be drawn twice as big, but the reported text extents will not be doubled. They will change slightly due to hinting (so you can't assume that metrics are independent of the transformation matrix), but otherwise will remain unchanged.

  `xBearing`

    [numeric] the horizontal distance from the origin to the leftmost part of the glyphs as drawn. Positive if the glyphs lie entirely to the right of the origin.

  `yBearing`

    [numeric] the vertical distance from the origin to the topmost part of the glyphs as drawn. Positive only if the glyphs lie completely below the origin; will usually be negative.

  `width`

    [numeric] width of the glyphs as drawn

  `height`

    [numeric] height of the glyphs as drawn

  `xAdvance`

    [numeric] distance to advance in the X direction after drawing these glyphs

  `yAdvance`

    [numeric] distance to advance in the Y direction after drawing these glyphs. Will typically be zero except for vertical text layout as found in East-Asian languages.

### Convenient Construction

`cairoScaledFont` is the equivalent of `cairoScaledFontCreate`.

### Author(s)

Derived by RGtkGen from GTK+ documentation

### References

http://www.cairographics.org/manual/cairo-cairo-scaled-font-t.html

[Package RGtk2 version 2.20.36.3 Index]