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
|
package tk
import (
"sync"
"src.elv.sh/pkg/cli/term"
"src.elv.sh/pkg/ui"
"src.elv.sh/pkg/wcwidth"
)
// TextView is a Widget for displaying text, with support for vertical
// scrolling.
//
// NOTE: This widget now always crops long lines. In future it should support
// wrapping and horizontal scrolling.
type TextView interface {
Widget
// ScrollBy scrolls the widget by the given delta. Positive values scroll
// down, and negative values scroll up.
ScrollBy(delta int)
// MutateState mutates the state.
MutateState(f func(*TextViewState))
// CopyState returns a copy of the State.
CopyState() TextViewState
}
// TextViewSpec specifies the configuration and initial state for a Widget.
type TextViewSpec struct {
// Key bindings.
Bindings Bindings
// If true, a vertical scrollbar will be shown when there are more lines
// that can be displayed, and the widget responds to Up and Down keys.
Scrollable bool
// State. Specifies the initial state if used in New.
State TextViewState
}
// TextViewState keeps mutable state of TextView.
type TextViewState struct {
Lines []string
First int
}
type textView struct {
// Mutex for synchronizing access to the state.
StateMutex sync.RWMutex
TextViewSpec
}
// NewTextView builds a TextView from the given spec.
func NewTextView(spec TextViewSpec) TextView {
if spec.Bindings == nil {
spec.Bindings = DummyBindings{}
}
return &textView{TextViewSpec: spec}
}
func (w *textView) Render(width, height int) *term.Buffer {
lines, first := w.getStateForRender(height)
needScrollbar := w.Scrollable && (first > 0 || first+height < len(lines))
textWidth := width
if needScrollbar {
textWidth--
}
bb := term.NewBufferBuilder(textWidth)
for i := first; i < first+height && i < len(lines); i++ {
if i > first {
bb.Newline()
}
bb.Write(wcwidth.Trim(lines[i], textWidth))
}
buf := bb.Buffer()
if needScrollbar {
scrollbar := VScrollbar{
Total: len(lines), Low: first, High: first + height}
buf.ExtendRight(scrollbar.Render(1, height))
}
return buf
}
func (w *textView) MaxHeight(width, height int) int {
return len(w.CopyState().Lines)
}
func (w *textView) getStateForRender(height int) (lines []string, first int) {
w.MutateState(func(s *TextViewState) {
if s.First > len(s.Lines)-height && len(s.Lines)-height >= 0 {
s.First = len(s.Lines) - height
}
lines, first = s.Lines, s.First
})
return
}
func (w *textView) Handle(event term.Event) bool {
if w.Bindings.Handle(w, event) {
return true
}
if w.Scrollable {
switch event {
case term.K(ui.Up):
w.ScrollBy(-1)
return true
case term.K(ui.Down):
w.ScrollBy(1)
return true
}
}
return false
}
func (w *textView) ScrollBy(delta int) {
w.MutateState(func(s *TextViewState) {
s.First += delta
if s.First < 0 {
s.First = 0
}
if s.First >= len(s.Lines) {
s.First = len(s.Lines) - 1
}
})
}
func (w *textView) MutateState(f func(*TextViewState)) {
w.StateMutex.Lock()
defer w.StateMutex.Unlock()
f(&w.State)
}
// CopyState returns a copy of the State while r-locking the StateMutex.
func (w *textView) CopyState() TextViewState {
w.StateMutex.RLock()
defer w.StateMutex.RUnlock()
return w.State
}
|
