This repository has been archived by the owner on Jan 16, 2024. It is now read-only.
-
Notifications
You must be signed in to change notification settings - Fork 7
/
context.go
73 lines (64 loc) · 1.52 KB
/
context.go
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
// SPDX-License-Identifier: Unlicense OR MIT
package layout
import (
"image"
"math"
"time"
"gioui.org/io/event"
"gioui.org/io/system"
"gioui.org/op"
"gioui.org/unit"
)
// Context carries the state needed by almost all layouts and widgets.
// A zero value Context never returns events, map units to pixels
// with a scale of 1.0, and returns the zero time from Now.
type Context struct {
// Constraints track the constraints for the active widget or
// layout.
Constraints Constraints
Config system.Config
Queue event.Queue
*op.Ops
}
// NewContext is a shorthand for
//
// Context{
// Ops: ops,
// Queue: q,
// Config: cfg,
// Constraints: Exact(size),
// }
//
// NewContext calls ops.Reset.
func NewContext(ops *op.Ops, q event.Queue, cfg system.Config, size image.Point) Context {
ops.Reset()
return Context{
Ops: ops,
Queue: q,
Config: cfg,
Constraints: Exact(size),
}
}
// Now returns the configuration time or the zero time.
func (c Context) Now() time.Time {
if c.Config == nil {
return time.Time{}
}
return c.Config.Now()
}
// Px maps the value to pixels. If no configuration is set,
// Px returns the rounded value of v.
func (c Context) Px(v unit.Value) int {
if c.Config == nil {
return int(math.Round(float64(v.V)))
}
return c.Config.Px(v)
}
// Events returns the events available for the key. If no
// queue is configured, Events returns nil.
func (c Context) Events(k event.Tag) []event.Event {
if c.Queue == nil {
return nil
}
return c.Queue.Events(k)
}