basicfont - ActiveState ActiveGo 1.8

Package basicfont

import ""

Overview ▾

Package basicfont provides fixed-size font faces.


Face7x13 is a Face derived from the public domain X11 misc-fixed font files.

At the moment, it holds the printable characters in ASCII starting with space, and the Unicode replacement character U+FFFD.

Its data is entirely self-contained and does not require loading from separate files.

var Face7x13 = &Face{
    Advance: 7,
    Width:   6,
    Height:  13,
    Ascent:  11,
    Descent: 2,
    Mask:    mask7x13,
    Ranges: []Range{
        {'\u0020', '\u007f', 0},
        {'\ufffd', '\ufffe', 95},

type Face

Face is a basic font face whose glyphs all have the same metrics.

It is safe to use concurrently.

type Face struct {
    // Advance is the glyph advance, in pixels.
    Advance int
    // Width is the glyph width, in pixels.
    Width int
    // Height is the inter-line height, in pixels.
    Height int
    // Ascent is the glyph ascent, in pixels.
    Ascent int
    // Descent is the glyph descent, in pixels.
    Descent int
    // Left is the left side bearing, in pixels. A positive value means that
    // all of a glyph is to the right of the dot.
    Left int

    // Mask contains all of the glyph masks. Its width is typically the Face's
    // Width, and its height a multiple of the Face's Height.
    Mask image.Image
    // Ranges map runes to sub-images of Mask. The rune ranges must not
    // overlap, and must be in increasing rune order.
    Ranges []Range

func (*Face) Close

func (f *Face) Close() error

func (*Face) Glyph

func (f *Face) Glyph(dot fixed.Point26_6, r rune) (
    dr image.Rectangle, mask image.Image, maskp image.Point, advance fixed.Int26_6, ok bool)

func (*Face) GlyphAdvance

func (f *Face) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool)

func (*Face) GlyphBounds

func (f *Face) GlyphBounds(r rune) (bounds fixed.Rectangle26_6, advance fixed.Int26_6, ok bool)

func (*Face) Kern

func (f *Face) Kern(r0, r1 rune) fixed.Int26_6

func (*Face) Metrics

func (f *Face) Metrics() font.Metrics

type Range

Range maps a contiguous range of runes to vertically adjacent sub-images of a Face's Mask image. The rune range is inclusive on the low end and exclusive on the high end.

If Low <= r && r < High, then the rune r is mapped to the sub-image of Face.Mask whose bounds are image.Rect(0, y*h, Face.Width, (y+1)*h), where y = (int(r-Low) + Offset) and h = (Face.Ascent + Face.Descent).

type Range struct {
    Low, High rune
    Offset    int