// Copyright 2015 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. //go:generate go run gen.go // Package basicfont provides fixed-size font faces. package basicfont // import "golang.org/x/image/font/basicfont" import ( "image" "golang.org/x/image/font" "golang.org/x/image/math/fixed" ) // 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 } // 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}, }, } // 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 (f *Face) Close() error { return nil } func (f *Face) Kern(r0, r1 rune) fixed.Int26_6 { return 0 } func (f *Face) Metrics() font.Metrics { return font.Metrics{ Height: fixed.I(f.Height), Ascent: fixed.I(f.Ascent), Descent: fixed.I(f.Descent), } } 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) { loop: for _, rr := range [2]rune{r, '\ufffd'} { for _, rng := range f.Ranges { if rr < rng.Low || rng.High <= rr { continue } maskp.Y = (int(rr-rng.Low) + rng.Offset) * (f.Ascent + f.Descent) ok = true break loop } } if !ok { return image.Rectangle{}, nil, image.Point{}, 0, false } x := int(dot.X+32)>>6 + f.Left y := int(dot.Y+32) >> 6 dr = image.Rectangle{ Min: image.Point{ X: x, Y: y - f.Ascent, }, Max: image.Point{ X: x + f.Width, Y: y + f.Descent, }, } return dr, f.Mask, maskp, fixed.I(f.Advance), true } func (f *Face) GlyphBounds(r rune) (bounds fixed.Rectangle26_6, advance fixed.Int26_6, ok bool) { return fixed.R(0, -f.Ascent, f.Width, +f.Descent), fixed.I(f.Advance), true } func (f *Face) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool) { return fixed.I(f.Advance), true }