mirror of
https://git.sr.ht/~eliasnaur/gio
synced 2026-07-01 07:35:40 +00:00
Elias Naur
bef7c39e4c
There is now a single shaping implementation, Shaper, for all fonts, replacing Family that only covered a single typeface. A typeface is identified by a name, where the empty string denotes the default typeface. Font is introduced to specify a particular font from the typeface, style, weight and size. Face is changed to an interface for a particular layout and shaping method. The text/shape package is renamed to text/opentype and contains a Face implementation based on golang.org/x/image/font/sfnt. Signed-off-by: Elias Naur <mail@eliasnaur.com>
110 lines
2.1 KiB
Go
110 lines
2.1 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
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package text
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import (
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"gioui.org/op/paint"
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"gioui.org/unit"
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"golang.org/x/image/math/fixed"
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)
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// Shaper implements layout and shaping of text and a cache of
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// computed results.
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//
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// Specify the default and fallback font by calling Register with the
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// empty Font.
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type Shaper struct {
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faces map[Font]*face
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}
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type face struct {
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face Face
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layoutCache layoutCache
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pathCache pathCache
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}
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func (s *Shaper) Register(font Font, tf Face) {
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if s.faces == nil {
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s.faces = make(map[Font]*face)
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}
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// Treat all font sizes equally.
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font.Size = unit.Value{}
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if font.Weight == 0 {
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font.Weight = Normal
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}
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s.faces[font] = &face{
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face: tf,
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}
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}
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func (s *Shaper) Layout(c unit.Converter, font Font, str string, opts LayoutOptions) *Layout {
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tf := s.faceForFont(font)
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return tf.layout(fixed.I(c.Px(font.Size)), str, opts)
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}
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func (s *Shaper) Shape(c unit.Converter, font Font, str String) paint.ClipOp {
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tf := s.faceForFont(font)
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return tf.shape(fixed.I(c.Px(font.Size)), str)
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}
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func (s *Shaper) faceForStyle(font Font) *face {
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tf := s.faces[font]
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if tf == nil {
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font := font
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font.Weight = Normal
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tf = s.faces[font]
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}
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if tf == nil {
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font := font
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font.Style = Regular
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tf = s.faces[font]
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}
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if tf == nil {
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font := font
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font.Style = Regular
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font.Weight = Normal
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tf = s.faces[font]
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}
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return tf
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}
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func (s *Shaper) faceForFont(font Font) *face {
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font.Size = unit.Value{}
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tf := s.faceForStyle(font)
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if tf == nil {
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font.Typeface = ""
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tf = s.faceForStyle(font)
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}
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if tf == nil {
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panic("no default typeface defined")
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}
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return tf
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}
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func (t *face) layout(ppem fixed.Int26_6, str string, opts LayoutOptions) *Layout {
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lk := layoutKey{
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ppem: ppem,
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str: str,
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opts: opts,
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}
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if l, ok := t.layoutCache.Get(lk); ok {
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return l
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}
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l := t.face.Layout(ppem, str, opts)
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t.layoutCache.Put(lk, l)
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return l
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}
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func (t *face) shape(ppem fixed.Int26_6, str String) paint.ClipOp {
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pk := pathKey{
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ppem: ppem,
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str: str.String,
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}
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if clip, ok := t.pathCache.Get(pk); ok {
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return clip
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}
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clip := t.face.Shape(ppem, str)
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t.pathCache.Put(pk, clip)
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return clip
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}
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