blob: 12d39f5cf8d02e8430653c6e57e036303b4ca00b (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
// SPDX-License-Identifier: Unlicense OR MIT
package text
import (
"io"
"gioui.org/op/clip"
"golang.org/x/image/math/fixed"
)
// A Line contains the measurements of a line of text.
type Line struct {
Layout Layout
// Width is the width of the line.
Width fixed.Int26_6
// Ascent is the height above the baseline.
Ascent fixed.Int26_6
// Descent is the height below the baseline, including
// the line gap.
Descent fixed.Int26_6
// Bounds is the visible bounds of the line.
Bounds fixed.Rectangle26_6
}
type Layout struct {
Text string
Advances []fixed.Int26_6
}
// Style is the font style.
type Style int
// Weight is a font weight, in CSS units subtracted 400 so the zero value
// is normal text weight.
type Weight int
// Font specify a particular typeface variant, style and weight.
type Font struct {
Typeface Typeface
Variant Variant
Style Style
// Weight is the text weight. If zero, Normal is used instead.
Weight Weight
}
// Face implements text layout and shaping for a particular font. All
// methods must be safe for concurrent use.
type Face interface {
Layout(ppem fixed.Int26_6, maxWidth int, txt io.Reader) ([]Line, error)
Shape(ppem fixed.Int26_6, str Layout) clip.PathSpec
}
// Typeface identifies a particular typeface design. The empty
// string denotes the default typeface.
type Typeface string
// Variant denotes a typeface variant such as "Mono" or "Smallcaps".
type Variant string
type Alignment uint8
const (
Start Alignment = iota
End
Middle
)
const (
Regular Style = iota
Italic
)
const (
Thin Weight = 100 - 400
Hairline Weight = Thin
ExtraLight Weight = 200 - 400
UltraLight Weight = ExtraLight
Light Weight = 300 - 400
Normal Weight = 400 - 400
Medium Weight = 500 - 400
SemiBold Weight = 600 - 400
DemiBold Weight = SemiBold
Bold Weight = 700 - 400
ExtraBold Weight = 800 - 400
UltraBold Weight = ExtraBold
Black Weight = 900 - 400
Heavy Weight = Black
ExtraBlack Weight = 950 - 400
UltraBlack Weight = ExtraBlack
)
func (a Alignment) String() string {
switch a {
case Start:
return "Start"
case End:
return "End"
case Middle:
return "Middle"
default:
panic("invalid Alignment")
}
}
func (s Style) String() string {
switch s {
case Regular:
return "Regular"
case Italic:
return "Italic"
default:
panic("invalid Style")
}
}
func (w Weight) String() string {
switch w {
case Thin:
return "Thin"
case ExtraLight:
return "ExtraLight"
case Light:
return "Light"
case Normal:
return "Normal"
case Medium:
return "Medium"
case SemiBold:
return "SemiBold"
case Bold:
return "Bold"
case ExtraBold:
return "ExtraBold"
case Black:
return "Black"
case ExtraBlack:
return "ExtraBlack"
default:
panic("invalid Weight")
}
}
// weightDistance returns the distance value between two font weights.
func weightDistance(wa Weight, wb Weight) int {
// Avoid dealing with negative Weight values.
a := int(wa) + 400
b := int(wb) + 400
diff := a - b
if diff < 0 {
return -diff
}
return diff
}
|
