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92 lines
1.7 KiB
Go
92 lines
1.7 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/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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}
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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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