forked from joejulian/gio
Elias Naur
7bf3265ccd
Instead of
type Contraints struct {
Width, Height Constraint
}
use
type Constraints struct {
Min, Max image.Point
}
which leads to simpler use. For example, the Min method is trivally replaced by
the field, and the RigidConstraints constructor is no longer a net win.
API Change. Rewrites:
gofmt -r 'gtx.Constraints.Min() -> gtx.Constraints.Min'
gofmt -r 'gtx.Constraints.Width.Min -> gtx.Constraints.Min.X'
gofmt -r 'gtx.Constraints.Height.Min -> gtx.Constraints.Min.Y'
gofmt -r 'gtx.Constraints.Height.Max -> gtx.Constraints.Max.Y'
gofmt -r 'gtx.Constraints.Width.Max -> gtx.Constraints.Max.X'
Signed-off-by: Elias Naur <mail@eliasnaur.com>
83 lines
2.0 KiB
Go
83 lines
2.0 KiB
Go
// 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
|
|
// Dimensions track the result of the most recent layout
|
|
// operation.
|
|
Dimensions Dimensions
|
|
|
|
cfg system.Config
|
|
queue event.Queue
|
|
*op.Ops
|
|
}
|
|
|
|
// layout a widget with a set of constraints and return its
|
|
// dimensions. The widget dimensions are constrained and the previous
|
|
// constraints are restored after layout.
|
|
func ctxLayout(gtx *Context, cs Constraints, w Widget) Dimensions {
|
|
saved := gtx.Constraints
|
|
gtx.Constraints = cs
|
|
gtx.Dimensions = Dimensions{}
|
|
w()
|
|
gtx.Dimensions.Size = cs.Constrain(gtx.Dimensions.Size)
|
|
gtx.Constraints = saved
|
|
return gtx.Dimensions
|
|
}
|
|
|
|
// Reset the context. The constraints' minimum and maximum values are
|
|
// set to the size.
|
|
func (c *Context) Reset(q event.Queue, cfg system.Config, size image.Point) {
|
|
c.Constraints = Constraints{Min: size, Max: size}
|
|
c.Dimensions = Dimensions{}
|
|
c.cfg = cfg
|
|
c.queue = q
|
|
if c.Ops == nil {
|
|
c.Ops = new(op.Ops)
|
|
}
|
|
c.Ops.Reset()
|
|
}
|
|
|
|
// Now returns the configuration time or the zero time.
|
|
func (c *Context) Now() time.Time {
|
|
if c.cfg == nil {
|
|
return time.Time{}
|
|
}
|
|
return c.cfg.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.cfg == nil {
|
|
return int(math.Round(float64(v.V)))
|
|
}
|
|
return c.cfg.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)
|
|
}
|