mirror of
https://git.sr.ht/~eliasnaur/gio
synced 2026-07-01 07:35:40 +00:00
Elias Naur
16d2a3ac0a
In preparation for using Shaper with an io.Reader, rework the API to not refer to strings. In particular, introduce Glyph for holding the rune in addition to the advance. For fast traversing of the underlying text, add Len to Line with the UTF8 length. Layout is a useless wrapper around []Line; remove it while we're here. Signed-off-by: Elias Naur <mail@eliasnaur.com>
135 lines
2.9 KiB
Go
135 lines
2.9 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
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package text
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import (
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"golang.org/x/image/font"
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"gioui.org/op"
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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.
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type Shaper interface {
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// Layout a text according to a set of options.
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Layout(c unit.Converter, font Font, str string, opts LayoutOptions) []Line
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// Shape a line of text previously laid out by Layout.
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Shape(c unit.Converter, font Font, str string, layout []Glyph) op.CallOp
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Metrics(c unit.Converter, font Font) font.Metrics
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}
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// FontRegistry implements layout and shaping of text and a cache of
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// computed results.
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//
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// If a font matches no registered shape, FontRegistry falls back to the
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// first registered face.
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type FontRegistry struct {
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def Typeface
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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 *FontRegistry) Register(font Font, tf Face) {
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if s.faces == nil {
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s.def = font.Typeface
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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 *FontRegistry) Layout(c unit.Converter, font Font, str string, opts LayoutOptions) []Line {
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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 *FontRegistry) Shape(c unit.Converter, font Font, str string, layout []Glyph) op.CallOp {
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tf := s.faceForFont(font)
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return tf.shape(fixed.I(c.Px(font.Size)), str, layout)
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}
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func (s *FontRegistry) Metrics(c unit.Converter, font Font) font.Metrics {
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tf := s.faceForFont(font)
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return tf.metrics(fixed.I(c.Px(font.Size)))
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}
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func (s *FontRegistry) 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 *FontRegistry) 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 = s.def
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tf = s.faceForStyle(font)
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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) []Line {
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if t == nil {
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return nil
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}
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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, layout []Glyph) op.CallOp {
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if t == nil {
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return op.CallOp{}
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}
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pk := pathKey{
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ppem: ppem,
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str: str,
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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, layout)
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t.pathCache.Put(pk, clip)
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return clip
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}
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func (t *face) metrics(ppem fixed.Int26_6) font.Metrics {
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return t.face.Metrics(ppem)
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}
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