ui/layout: rename simple.go to layout.go

A more appropriate name. Signed-off-by: Elias Naur <mail@eliasnaur.com>
2026-07-07 18:35:34 +00:00 · 2019-04-27 22:24:20 +02:00
parent f60906b8e2
commit 56133632c6
1 changed files with 0 additions and 0 deletions
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package layout
+
+import (
+	"image"
+	"math"
+
+	"gioui.org/ui"
+)
+
+type Widget interface {
+	Layout(ops *ui.Ops, cs Constraints) Dimens
+}
+
+type Constraints struct {
+	Width  Constraint
+	Height Constraint
+}
+
+type Constraint struct {
+	Min, Max int
+}
+
+type Dimens struct {
+	Size     image.Point
+	Baseline int
+}
+
+type Axis uint8
+
+type F func(ops *ui.Ops, cs Constraints) Dimens
+
+const (
+	Horizontal Axis = iota
+	Vertical
+)
+
+func (c Constraint) Constrain(v int) int {
+	if v < c.Min {
+		return c.Min
+	} else if v > c.Max {
+		return c.Max
+	}
+	return v
+}
+
+func (c Constraints) Constrain(p image.Point) image.Point {
+	return image.Point{X: c.Width.Constrain(p.X), Y: c.Height.Constrain(p.Y)}
+}
+
+func (c Constraints) Expand() Constraints {
+	return Constraints{Width: c.Width.Expand(), Height: c.Height.Expand()}
+}
+
+func (c Constraint) Expand() Constraint {
+	return Constraint{Min: c.Max, Max: c.Max}
+}
+func (c Constraints) Loose() Constraints {
+	return Constraints{Width: c.Width.Loose(), Height: c.Height.Loose()}
+}
+
+func (c Constraint) Loose() Constraint {
+	return Constraint{Max: c.Max}
+}
+
+// ExactConstraints returns the constraints that exactly represents the
+// given dimensions.
+func ExactConstraints(size image.Point) Constraints {
+	return Constraints{
+		Width:  Constraint{Min: size.X, Max: size.X},
+		Height: Constraint{Min: size.Y, Max: size.Y},
+	}
+}
+
+func (f F) Layout(ops *ui.Ops, cs Constraints) Dimens {
+	return f(ops, cs)
+}
+
+type Margins struct {
+	Top, Right, Bottom, Left ui.Value
+}
+
+func Margin(c *ui.Config, m Margins, w Widget) Widget {
+	return F(func(ops *ui.Ops, cs Constraints) Dimens {
+		mcs := cs
+		t, r, b, l := int(c.Pixels(m.Top)+0.5), int(c.Pixels(m.Right)+0.5), int(c.Pixels(m.Bottom)+0.5), int(c.Pixels(m.Left)+0.5)
+		if mcs.Width.Max != ui.Inf {
+			mcs.Width.Min -= l + r
+			mcs.Width.Max -= l + r
+			if mcs.Width.Min < 0 {
+				mcs.Width.Min = 0
+			}
+			if mcs.Width.Max < mcs.Width.Min {
+				mcs.Width.Max = mcs.Width.Min
+			}
+		}
+		if mcs.Height.Max != ui.Inf {
+			mcs.Height.Min -= t + b
+			mcs.Height.Max -= t + b
+			if mcs.Height.Min < 0 {
+				mcs.Height.Min = 0
+			}
+			if mcs.Height.Max < mcs.Height.Min {
+				mcs.Height.Max = mcs.Height.Min
+			}
+		}
+		ops.Begin()
+		ui.OpTransform{Transform: ui.Offset(toPointF(image.Point{X: l, Y: t}))}.Add(ops)
+		dims := w.Layout(ops, mcs)
+		ops.End().Add(ops)
+		return Dimens{
+			Size:     cs.Constrain(dims.Size.Add(image.Point{X: r + l, Y: t + b})),
+			Baseline: dims.Baseline + t,
+		}
+	})
+}
+
+func EqualMargins(v ui.Value) Margins {
+	return Margins{Top: v, Right: v, Bottom: v, Left: v}
+}
+
+func isInf(v ui.Value) bool {
+	return math.IsInf(float64(v.V), 1)
+}
+
+func Capped(c *ui.Config, maxWidth, maxHeight ui.Value, wt Widget) Widget {
+	return F(func(ops *ui.Ops, cs Constraints) Dimens {
+		if !isInf(maxWidth) {
+			mw := int(c.Pixels(maxWidth) + .5)
+			if mw < cs.Width.Min {
+				mw = cs.Width.Min
+			}
+			if mw < cs.Width.Max {
+				cs.Width.Max = mw
+			}
+		}
+		if !isInf(maxHeight) {
+			mh := int(c.Pixels(maxHeight) + 0.5)
+			if mh < cs.Height.Min {
+				mh = cs.Height.Min
+			}
+			if mh < cs.Height.Max {
+				cs.Height.Max = mh
+			}
+		}
+		return wt.Layout(ops, cs)
+	})
+}
+
+func Sized(c *ui.Config, width, height ui.Value, wt Widget) Widget {
+	return F(func(ops *ui.Ops, cs Constraints) Dimens {
+		if h := int(c.Pixels(height) + 0.5); h != 0 {
+			if cs.Height.Min < h {
+				cs.Height.Min = h
+			}
+			if h < cs.Height.Max {
+				cs.Height.Max = h
+			}
+		}
+		if w := int(c.Pixels(width) + .5); w != 0 {
+			if cs.Width.Min < w {
+				cs.Width.Min = w
+			}
+			if w < cs.Width.Max {
+				cs.Width.Max = w
+			}
+		}
+		return wt.Layout(ops, cs)
+	})
+}
+
+func Expand(w Widget) Widget {
+	return F(func(ops *ui.Ops, cs Constraints) Dimens {
+		if cs.Height.Max != ui.Inf {
+			cs.Height.Min = cs.Height.Max
+		}
+		if cs.Width.Max != ui.Inf {
+			cs.Width.Min = cs.Width.Max
+		}
+		return w.Layout(ops, cs)
+	})
+}
+
+func Align(alignment Direction, w Widget) Widget {
+	return F(func(ops *ui.Ops, cs Constraints) Dimens {
+		ops.Begin()
+		dims := w.Layout(ops, cs.Loose())
+		block := ops.End()
+		sz := dims.Size
+		if cs.Width.Max != ui.Inf {
+			sz.X = cs.Width.Max
+		}
+		if cs.Height.Max != ui.Inf {
+			sz.Y = cs.Height.Max
+		}
+		var p image.Point
+		switch alignment {
+		case N, S, Center:
+			p.X = (sz.X - dims.Size.X) / 2
+		case NE, SE, E:
+			p.X = sz.X - dims.Size.X
+		}
+		switch alignment {
+		case W, Center, E:
+			p.Y = (sz.Y - dims.Size.Y) / 2
+		case SW, S, SE:
+			p.Y = sz.Y - dims.Size.Y
+		}
+		ops.Begin()
+		ui.OpTransform{Transform: ui.Offset(toPointF(p))}.Add(ops)
+		block.Add(ops)
+		ops.End().Add(ops)
+		return Dimens{
+			Size:     sz,
+			Baseline: dims.Baseline,
+		}
+	})
+}