forked from joejulian/gio
Elias Naur
4c220f4554
First, replace LayoutOptions with an explicit maximum width parameter. The single-field option struct doesn't carry its weight, and I don't think we'll see more global layout options in the future. Rather, I expect options to cover spans of text or be part of a Font. Second, replace the unit.Converter with an scaled text size. It's simpler and allow the Editor and similar widgets to easily detect whether their cached layouts are stale. Package text no longer depends on package unit, which is now dealt with at the widget-level only. Finally, remove the Size field from Font. It was a design mistake: a Font is assumed to cover all sizes, as evidenced by the FontRegistry disregarding Size when looking up fonts. Signed-off-by: Elias Naur <mail@eliasnaur.com>
94 lines
1.8 KiB
Go
94 lines
1.8 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
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package text
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import (
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"io"
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"gioui.org/op"
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"golang.org/x/image/font"
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"golang.org/x/image/math/fixed"
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)
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// A Line contains the measurements of a line of text.
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type Line struct {
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Layout []Glyph
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// Len is the length in UTF8 bytes of the line.
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Len int
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// Width is the width of the line.
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Width fixed.Int26_6
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// Ascent is the height above the baseline.
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Ascent fixed.Int26_6
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// Descent is the height below the baseline, including
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// the line gap.
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Descent fixed.Int26_6
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// Bounds is the visible bounds of the line.
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Bounds fixed.Rectangle26_6
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}
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type Glyph struct {
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Rune rune
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Advance fixed.Int26_6
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}
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// Style is the font style.
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type Style int
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// Weight is a font weight, in CSS units.
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type Weight int
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// Font specify a particular typeface variant, style and weight.
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type Font struct {
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Typeface Typeface
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Variant Variant
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Style Style
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// Weight is the text weight. If zero, Normal is used instead.
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Weight Weight
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}
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// Face implements text layout and shaping for a particular font.
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type Face interface {
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Layout(ppem fixed.Int26_6, maxWidth int, txt io.Reader) ([]Line, error)
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Shape(ppem fixed.Int26_6, str []Glyph) op.CallOp
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Metrics(ppem fixed.Int26_6) font.Metrics
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}
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// Typeface identifies a particular typeface design. The empty
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// string denotes the default typeface.
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type Typeface string
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// Variant denotes a typeface variant such as "Mono" or "Smallcaps".
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type Variant string
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type Alignment uint8
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const (
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Start Alignment = iota
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End
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Middle
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)
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const (
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Regular Style = iota
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Italic
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)
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const (
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Normal Weight = 400
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Medium Weight = 500
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Bold Weight = 600
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)
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func (a Alignment) String() string {
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switch a {
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case Start:
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return "Start"
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case End:
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return "End"
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case Middle:
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return "Middle"
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default:
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panic("unreachable")
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}
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}
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