forked from joejulian/gio
Elias Naur
51 lines
1.2 KiB
Go
51 lines
1.2 KiB
Go
// SPDX-License-Identifier: Unlicense OR MIT
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package layout
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import (
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"image"
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"gioui.org/io/event"
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"gioui.org/io/system"
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"gioui.org/op"
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)
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// Context carries the state needed by almost all layouts and widgets.
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type Context struct {
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// Constraints track the constraints for the active widget or
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// layout.
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Constraints Constraints
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// Dimensions track the result of the most recent layout
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// operation.
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Dimensions Dimensions
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system.Config
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event.Queue
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*op.Ops
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}
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// layout a widget with a set of constraints and return its
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// dimensions. The widget dimensions are constrained abd the previous
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// constraints are restored after layout.
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func ctxLayout(gtx *Context, cs Constraints, w Widget) Dimensions {
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saved := gtx.Constraints
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gtx.Constraints = cs
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gtx.Dimensions = Dimensions{}
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w()
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gtx.Dimensions.Size = cs.Constrain(gtx.Dimensions.Size)
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gtx.Constraints = saved
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return gtx.Dimensions
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}
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// Reset the context. The constraints' minimum and maximum values are
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// set to the size.
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func (c *Context) Reset(cfg system.Config, size image.Point) {
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c.Constraints = RigidConstraints(size)
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c.Dimensions = Dimensions{}
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c.Config = cfg
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if c.Ops == nil {
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c.Ops = new(op.Ops)
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}
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c.Ops.Reset()
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}
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